chore: ignore MagicMock test artifacts

Co-authored-by: CommandCodeBot <noreply@commandcode.ai>

.gitea/workflows/release.yml

@@ -0,0 +1,230 @@
+# Fenris release workflow — release path on Coolify-hosted Gitea runner.
+# The runner is repository-scoped and executes package build, signing, validation,
+# registry publication, and release attachment. Spec: §5, issue #52
+name: Release
+
+on:
+  push:
+    tags:
+      - 'v*'
+  workflow_dispatch:
+
+# Built-in Gitea token needs write access for release assets and package registry.
+permissions:
+  contents: read
+  releases: write
+  packages: write
+
+jobs:
+  release:
+    runs-on: [self-hosted]
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Validate release tag and notes
+        run: |
+          set -euo pipefail
+          VERSION="$(sed -n 's/^version = "\(.*\)"/\1/p' pyproject.toml)"
+          if [ -z "${VERSION}" ]; then
+            echo "::error::could not determine the project version"
+            exit 1
+          fi
+          if [ "${GITHUB_EVENT_NAME}" != "workflow_dispatch" ]; then
+            EXPECTED_TAG="v${VERSION}"
+            ACTUAL_TAG="${GITHUB_REF#refs/tags/}"
+            if [ "${ACTUAL_TAG}" != "${EXPECTED_TAG}" ]; then
+              echo "::error::tag ${ACTUAL_TAG} does not match ${EXPECTED_TAG}"
+              exit 1
+            fi
+          fi
+          python3 scripts/extract_changelog.py CHANGELOG.md "${VERSION}" \
+            --footer packaging/release-footer.md > "${RUNNER_TEMP}/release-body.md"
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.12'
+
+      - name: Install build dependencies
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y gnupg2 rpm python3-venv
+          python3 -m venv /tmp/fenris-ci
+          /tmp/fenris-ci/bin/pip install --quiet build
+          echo "/tmp/fenris-ci/bin" >> "$GITHUB_PATH"
+          NFPM_VERSION=2.47.0
+          curl --fail --silent --show-error --location \
+            "https://github.com/goreleaser/nfpm/releases/download/v${NFPM_VERSION}/nfpm_${NFPM_VERSION}_Linux_x86_64.tar.gz" \
+            -o /tmp/nfpm.tar.gz
+          sudo tar -xzf /tmp/nfpm.tar.gz -C /usr/local/bin nfpm
+          nfpm --version
+
+      - name: Build packages
+        run: make package
+
+      - name: Import packaging key
+        env:
+          GPG_PRIVATE_KEY: ${{ secrets.GPG_PRIVATE_KEY }}
+        run: |
+          set -euo pipefail
+          if [ -z "${GPG_PRIVATE_KEY}" ]; then
+            echo "::error::GPG_PRIVATE_KEY repository secret is not configured"
+            exit 1
+          fi
+          printf '%s\n' "${GPG_PRIVATE_KEY}" | gpg --batch --import
+          SECRET_FINGERPRINT="$(gpg --batch --list-secret-keys --with-colons 'packaging@bongbetic.com' | awk -F: '$1 == "fpr" { print $10; exit }')"
+          PUBLIC_FINGERPRINT="$(gpg --batch --show-keys --with-colons packaging/keys/fenris-packaging.asc | awk -F: '$1 == "fpr" { print $10; exit }')"
+          if [ -z "${PUBLIC_FINGERPRINT}" ]; then
+            echo "::error::packaging/keys/fenris-packaging.asc has no OpenPGP key"
+            exit 1
+          fi
+          if [ "${SECRET_FINGERPRINT}" != "${PUBLIC_FINGERPRINT}" ]; then
+            echo "::error::packaging public key does not match imported private key"
+            exit 1
+          fi
+          echo "Packaging key fingerprint verified: ${PUBLIC_FINGERPRINT}"
+
+      - name: Sign RPM payload
+        run: make sign-rpm
+
+      - name: Generate and clearsign SHA256SUMS
+        run: |
+          set -euo pipefail
+          VERSION="$(sed -n 's/^version = "\(.*\)"/\1/p' pyproject.toml)"
+          cd dist
+          sha256sum "fenris_${VERSION}_amd64.deb" \
+            "fenris-${VERSION}-1.x86_64.rpm" > SHA256SUMS
+          gpg --batch --yes --clearsign --local-user packaging@bongbetic.com SHA256SUMS
+
+      - name: Validate signatures and checksums
+        run: |
+          set -euo pipefail
+          VERSION="$(sed -n 's/^version = "\(.*\)"/\1/p' pyproject.toml)"
+          RPM="fenris-${VERSION}-1.x86_64.rpm"
+          RPM_VERIFY="$(rpm -Kv "dist/${RPM}" 2>&1)"
+          printf '%s\n' "${RPM_VERIFY}"
+          printf '%s\n' "${RPM_VERIFY}" | grep -Eiq 'signature.*: *ok'
+          gpg --batch --verify dist/SHA256SUMS.asc
+          (cd dist && sha256sum -c SHA256SUMS)
+
+      - name: Remove packaging key material
+        if: always()
+        run: |
+          set +e
+          FINGERPRINT="$(gpg --batch --list-secret-keys --with-colons 'packaging@bongbetic.com' 2>/dev/null | awk -F: '$1 == "fpr" { print $10; exit }')"
+          if [ -n "${FINGERPRINT}" ]; then
+            gpg --batch --yes --delete-secret-keys "${FINGERPRINT}"
+            gpg --batch --yes --delete-keys "${FINGERPRINT}"
+          fi
+
+      - name: Determine version
+        id: version
+        run: echo "version=$(sed -n 's/^version = "\(.*\)"/\1/p' pyproject.toml)" >> "$GITHUB_OUTPUT"
+
+      - name: Upload deb packages to registry
+        env:
+          GITEA_PUBLISH_TOKEN: ${{ secrets.GITEAPACKAGETOKEN }}
+        run: |
+          set -euo pipefail
+          if [ -z "${GITEA_PUBLISH_TOKEN}" ]; then
+            echo "::error::GITEAPACKAGETOKEN repository secret is not configured"
+            exit 1
+          fi
+          VERSION=${{ steps.version.outputs.version }}
+          DEB="fenris_${VERSION}_amd64.deb"
+          for CODENAME in bookworm jammy noble; do
+            STATUS=$(curl --silent --show-error --user "xavierk:${GITEA_PUBLISH_TOKEN}" -X PUT \
+              -T "dist/${DEB}" -o /dev/null -w '%{http_code}' \
+              "https://git.bongbetic.com/api/packages/xavierk/debian/pool/${CODENAME}/main/upload" || true)
+            case "${STATUS}" in
+              200|201|204) echo "Debian ${CODENAME}: uploaded" ;;
+              409) echo "Debian ${CODENAME}: already exists, kept existing package" ;;
+              *) echo "::error::Debian ${CODENAME} upload failed with HTTP ${STATUS}"; exit 1 ;;
+            esac
+          done
+
+      - name: Upload RPM to registry
+        env:
+          GITEA_PUBLISH_TOKEN: ${{ secrets.GITEAPACKAGETOKEN }}
+        run: |
+          set -euo pipefail
+          VERSION=${{ steps.version.outputs.version }}
+          RPM="fenris-${VERSION}-1.x86_64.rpm"
+          STATUS=$(curl --silent --show-error --user "xavierk:${GITEA_PUBLISH_TOKEN}" -X PUT \
+            -T "dist/${RPM}" -o /dev/null -w '%{http_code}' \
+            "https://git.bongbetic.com/api/packages/xavierk/rpm/fenris/upload" || true)
+          case "${STATUS}" in
+            200|201|204) echo "RPM: uploaded" ;;
+            409) echo "RPM: already exists, kept existing package" ;;
+            *) echo "::error::RPM upload failed with HTTP ${STATUS}"; exit 1 ;;
+          esac
+
+      - name: Create Gitea release
+        env:
+          GITEA_PUBLISH_TOKEN: ${{ secrets.GITEAPACKAGETOKEN }}
+        run: |
+          set -euo pipefail
+          if [ -z "${GITEA_PUBLISH_TOKEN}" ]; then
+            echo "::error::GITEAPACKAGETOKEN repository secret is not configured"
+            exit 1
+          fi
+          VERSION=${{ steps.version.outputs.version }}
+          RELEASE_BODY="${RUNNER_TEMP}/release-body.md"
+          if [ ! -s "${RELEASE_BODY}" ]; then
+            echo "::error::validated release body is missing or empty"
+            exit 1
+          fi
+          EXISTING_RELEASE="${RUNNER_TEMP}/existing-release.json"
+          EXISTING=$(curl --silent --show-error -o "${EXISTING_RELEASE}" -w '%{http_code}' \
+            -H "Authorization: token ${GITEA_PUBLISH_TOKEN}" \
+            "https://git.bongbetic.com/api/v1/repos/xavierk/Fenris/releases/tags/v${VERSION}" || true)
+          case "${EXISTING}" in
+            200)
+              echo "Release v${VERSION} exists; resynchronizing its notes"
+              REQUEST="$(python3 scripts/release_request.py --version "${VERSION}" \
+                --body-file "${RELEASE_BODY}" --existing-release "${EXISTING_RELEASE}")"
+              ;;
+            404)
+              REQUEST="$(python3 scripts/release_request.py --version "${VERSION}" \
+                --body-file "${RELEASE_BODY}")"
+              ;;
+            *)
+              echo "::error::release lookup failed with HTTP ${EXISTING}"
+              exit 1
+              ;;
+          esac
+          METHOD="$(printf '%s' "${REQUEST}" | python3 -c "import json,sys; print(json.load(sys.stdin)['method'])")"
+          RELEASE_PATH="$(printf '%s' "${REQUEST}" | python3 -c "import json,sys; print(json.load(sys.stdin)['path'])")"
+          PAYLOAD="$(printf '%s' "${REQUEST}" | python3 -c "import json,sys; print(json.dumps(json.load(sys.stdin)['payload']))")"
+          curl --fail --silent --show-error -X "${METHOD}" \
+            -H "Authorization: token ${GITEA_PUBLISH_TOKEN}" \
+            -H "Content-Type: application/json" \
+            -d "${PAYLOAD}" \
+            "https://git.bongbetic.com/api/v1/repos/xavierk/Fenris${RELEASE_PATH}"
+
+      - name: Attach artifacts to release
+        env:
+          GITEA_PUBLISH_TOKEN: ${{ secrets.GITEAPACKAGETOKEN }}
+        run: |
+          set -euo pipefail
+          VERSION=${{ steps.version.outputs.version }}
+          # Get release ID for this tag
+          RELEASE_JSON=$(curl --fail --silent --show-error \
+            -H "Authorization: token ${GITEA_PUBLISH_TOKEN}" \
+            "https://git.bongbetic.com/api/v1/repos/xavierk/Fenris/releases/tags/v${VERSION}")
+          RELEASE_ID=$(printf '%s' "${RELEASE_JSON}" \
+            | python3 -c "import sys,json; print(json.load(sys.stdin)['id'])")
+          # Attach deb, rpm, and clearsigned checksums once.
+          for FILE in "dist/fenris_${VERSION}_amd64.deb" \
+                       "dist/fenris-${VERSION}-1.x86_64.rpm" \
+                       "dist/SHA256SUMS.asc"; do
+            ASSET_NAME="${FILE##*/}"
+            if python3 -c 'import json,sys; name=sys.argv[1]; sys.exit(0 if any(a.get("name") == name for a in json.load(sys.stdin).get("assets", [])) else 1)' "${ASSET_NAME}" <<<"${RELEASE_JSON}"; then
+              echo "${ASSET_NAME}: already attached"
+            else
+              curl --fail --silent --show-error -X POST \
+                -H "Authorization: token ${GITEA_PUBLISH_TOKEN}" \
+                -F "attachment=@${FILE}" \
+                "https://git.bongbetic.com/api/v1/repos/xavierk/Fenris/releases/${RELEASE_ID}/assets"
+            fi
+          done

.gitignore

@@ -1,4 +1,5 @@
 __pycache__/
+.pi/
 *.pyc
 .commandcode/
 data/fenris.pid
@@ -6,3 +7,15 @@ data/fenris.log
 data/history.jsonl
 data/hourly.jsonl
 plan-dash-changes.md
+
+# Packaging build artifacts
+build/
+dist/
+
+# Local tooling
+graphify-out/
+json
+src/fenris.egg-info/
+.pytest_cache/
+.venv/
+MagicMock*

AGENTS.md

@@ -0,0 +1,9 @@
+## Agent skills
+
+### Issue tracker
+
+Issues are tracked in Gitea using the authenticated `tea` CLI. See `docs/agents/issue-tracker.md`.
+
+### Domain docs
+
+This is a single-context repository. See `docs/agents/domain.md`.

CHANGELOG.md

@@ -0,0 +1,28 @@
+# Changelog
+
+<!--
+Maintainers add one user-facing entry to Unreleased with each change. A release
+commit bumps pyproject.toml, renames Unreleased to that bare-semver version and
+an ISO date, then restores an empty Unreleased section; tag that commit. Do not
+backfill releases from before this changelog.
+-->
+
+## [Unreleased]
+
+## [0.3.5] - 2026-09-14
+
+### Added
+
+- Show trustworthy first-use history, qualifying-day progress, and confidence in the dashboard.
+- Add an interactive daily-writes graph with hourly drill-down and evidence-anchored scenario windows.
+- Repair retained observation history safely and keep its retention state visible.
+- Present a unified monitoring status, drive-health context, and Fenris identity in the dashboard.
+- Remember accessible colour and motion preferences and keep the dashboard usable at constrained terminal sizes.
+
+## [0.3.4] - 2026-09-10
+
+### Added
+
+- Add Fenris identity and a polkit authentication notice to the dashboard.
+- Clarify monitoring continuity, deliberate pauses, and quitting in the dashboard and status output.
+- Add per-release notes with installation, verification, and rollback guidance.

CONTEXT.md

@@ -0,0 +1,93 @@
+# Fenris
+
+Fenris observes an NVMe drive’s real-world use and translates that history into an understandable endurance outlook.
+
+## Language
+
+**Observation history**:
+The persisted record of drive activity gathered while Fenris monitoring is enabled, retained across restarts and reboots.
+_Avoid_: Calibration data, temporary history
+
+**Observed usage habit**:
+The pattern of active, idle, and powered-off hours represented by the observation history, with recent sustained behavior carrying more relevance than distant behavior.
+_Avoid_: Current usage, benchmark workload
+
+**Usage-adjusted theoretical lifespan**:
+The theoretical time until the drive’s write endurance is exhausted if its observed usage habit continues; it is an endurance projection, not a predicted hardware-failure date.
+_Avoid_: Future life, actual lifespan, failure date
+
+**Projection confidence**:
+The degree to which the observation history is sufficiently long, complete, and stable to support the usage-adjusted theoretical lifespan.
+_Avoid_: Accuracy percentage, certainty
+
+**Monitoring period**:
+A span during which Fenris monitoring is enabled; powered-off time remains part of the usage habit, while deliberately disabled time does not.
+_Avoid_: Daemon uptime, calibration window
+
+**Observation store**:
+The single SQLite database at `/var/lib/fenris/observations.db` that persists the observation history, monitoring periods, hour observations, day aggregates, and endurance baseline.
+_Avoid_: Data directory, history.jsonl, the database (generic)
+
+**Store fault**:
+The condition where the observation store is present but cannot be read or trusted — unreadable, corrupt, or written by a newer Fenris — degrading every view that depends on it rather than crashing or guessing.
+_Avoid_: Database error, corruption, broken data
+
+**Hour observation**:
+One row per UTC hour in the observation store, recording that hour's usage-habit split into active, idle, powered-off, and unknown seconds, plus write/read deltas, thermal evidence, and coverage.
+_Avoid_: Hourly record, hourly.jsonl entry
+
+**Day aggregate**:
+One row per UTC day derived from hour observations; the grain at which usage-habit evidence is judged.
+_Avoid_: Daily summary, daily stats
+
+**Controller segment**:
+A span of observation history within which the drive's controller identity is unchanged and counters are monotonic; write deltas are never computed across a segment boundary.
+_Avoid_: Counter reset handling, drive swap detection
+
+**Degraded identity**:
+The condition where a controller segment's identity key is blank because no identifier rung produced a value; replacement detection then relies on write-counter continuity alone, and projection confidence is capped.
+_Avoid_: Identity error, unknown device, virtual drive
+
+**Endurance baseline**:
+The write-endurance value a projection consumes, chosen by precedence: a verified override when one exists, otherwise an unverified override, otherwise a coarse implied baseline derived from vendor wear — each labeled as such.
+_Avoid_: TBW value, failure threshold, max writes
+
+**Verified override**:
+A rated-TBW override with complete provenance whose applicability to the detected drive was confirmed by machine match or explicit user attestation; the strongest endurance baseline.
+_Avoid_: Confirmed TBW, trusted value
+
+**Unverified override**:
+A rated-TBW override knowingly stored with incomplete provenance; always presented as user-supplied, never as verified.
+_Avoid_: Forced entry, fallback baseline
+
+**Sustained regime**:
+The most recent stretch of the observation history over which the observed usage habit has been stable; the interval whose write rate the usage-adjusted theoretical lifespan consumes.
+_Avoid_: Current window, detection period
+
+**Habit change**:
+A sustained divergence between recent and earlier daily write rates that starts a new sustained regime.
+_Avoid_: Spike, anomaly
+
+**Scenario range**:
+The spread of lifespan projections computed from the 7-, 28-, and 90-day horizons of the observation history, shown in place of a statistical interval.
+_Avoid_: Confidence interval, error bar
+
+**Coverage**:
+The share of wall-clock seconds inside monitoring periods whose usage-habit classification is known rather than unknown.
+_Avoid_: Uptime, sample count
+
+**Collection run**:
+One scheduled or on-demand execution of the collector that interrogates the drive and extends the observation history.
+_Avoid_: Poll, daemon tick
+
+**Release**:
+A published version of Fenris: a version tag, its packages in the channel, and its human-readable change notes, all together; a bare tag is not one.
+_Avoid_: Tag, upload, build
+
+**Rollback**:
+Returning to an earlier release by restoring an observation-store snapshot and then installing that release; installing an older package over a newer store is unsupported.
+_Avoid_: Downgrade, version pinning (as a promise)
+
+**Deliberate disable**:
+A monitoring pause made through Fenris's own control path, closing the monitoring period so the paused time is excluded from the usage habit.
+_Avoid_: Manual stop, service stop

Makefile

@@ -0,0 +1,381 @@
+# Fenris Makefile
+# Spec: §10.1-10.6
+
+SHELL := /bin/bash
+PYTHON := python3
+VENV_DIR := /opt/fenris
+VENDOR_DIR := $(VENV_DIR)/vendor
+BIN_DIR := /usr/local/bin
+LIBEXEC_DIR := /usr/libexec/fenris
+UNIT_DIR := /etc/systemd/system
+POLKIT_DIR := /usr/share/polkit-1/actions
+CONF_DIR := /etc/fenris
+DATA_DIR := /var/lib/fenris
+
+# Placement manifest
+MANIFEST := $(DATA_DIR)/manifest.txt
+
+# Legacy history path (IN-4)
+LEGACY_HISTORY := ./data/history.jsonl
+
+.PHONY: help install upgrade uninstall purge update-deps test lint check-python check-smartctl import-legacy stage package-deb package-rpm package-xbps package generate-test-key sign-rpm sign-xbps checksums clearsign release release-run release-dry-run xbps-publish xbps-publish-dry-run clean
+
+help:
+	@echo "Fenris NVMe endurance monitor"
+	@echo ""
+	@echo "Targets:"
+	@echo "  install      - Install Fenris (builds wheel, installs to /opt/fenris)"
+	@echo "  upgrade      - Upgrade Fenris (reinstall wheel, sync units)"
+	@echo "  uninstall    - Uninstall Fenris (preserves config and store)"
+	@echo "  purge        - Remove everything including config and store"
+	@echo "  test         - Run tests"
+	@echo "  lint         - Run linter"
+	@echo "  update-deps  - Update dependency pins"
+	@echo "  stage        - Stage packaging tree for nfpm"
+	@echo "  package      - Build deb + rpm packages"
+	@echo "  package-deb  - Build deb package only"
+	@echo "  package-rpm  - Build rpm package only"
+	@echo "  package-xbps - Build XBPS package only"
+	@echo "  sign-xbps    - Sign XBPS package with signing key"
+	@echo "  generate-test-key  - Create throwaway GPG key for CI/testing"
+	@echo "  sign-rpm     - Sign RPM payload with packaging key"
+	@echo "  checksums    - Generate SHA256SUMS manifest"
+	@echo "  clearsign    - Clearsign SHA256SUMS with packaging key"
+	@echo "  release      - Full release (build, sign, checksum, print upload steps)"
+	@echo "  release-run  - Execute the full release flow via scripts/release.sh"
+	@echo "  release-dry-run - Dry-run of the release flow (prints commands only)"
+	@echo "  xbps-publish - Publish XBPS package to distribution repository"
+	@echo "  xbps-publish-dry-run - Dry-run of XBPS publication (prints commands only)"
+	@echo "  clean        - Remove build artifacts"
+
+# ─── Pre-install gates ──────────────────────────────────────────────────────
+
+check-python:
+	@echo "=== Verifying Python ≥ 3.10 ==="
+	@$(PYTHON) -c "import sys; v=sys.version_info; exit(0 if (v>=(3,10)) else 1)" || { echo "Error: Python 3.10+ required (found $$($(PYTHON) --version 2>&1))"; exit 1; }
+
+check-smartctl:
+	@echo "=== Verifying smartctl ==="
+	@smartctl --version 2>/dev/null | head -1 || { echo "Error: smartctl not found (install smartmontools)"; exit 1; }
+
+# ─── Build ──────────────────────────────────────────────────────────────────
+
+dist/fenris-*.whl: pyproject.toml src/fenris/*.py
+	@mkdir -p dist
+	$(PYTHON) -m pip wheel --no-deps --wheel-dir dist .
+
+# ─── Install ────────────────────────────────────────────────────────────────
+
+install: check-python check-smartctl dist/fenris-*.whl
+	@echo "=== Creating directories ==="
+	@sudo mkdir -p $(LIBEXEC_DIR)
+	@sudo mkdir -p $(CONF_DIR)
+	@sudo mkdir -p $(POLKIT_DIR)
+	
+	@echo "=== Creating data directory (root-written, group-read) ==="
+	@sudo groupadd -f fenris
+	@sudo install -d -o root -g fenris -m 2750 $(DATA_DIR)
+	
+	@echo "=== Installing version-neutral runtime packages ==="
+	@sudo rm -rf $(VENV_DIR)
+	@sudo install -d -m 0755 $(VENDOR_DIR)
+	@sudo $(PYTHON) -m pip install --disable-pip-version-check --no-compile --target $(VENDOR_DIR) -r requirements.txt dist/fenris-*.whl --quiet
+	
+	@echo "=== Installing wrapper ==="
+	@sudo install -m 0755 scripts/fenris $(BIN_DIR)/fenris
+	
+	@echo "=== Installing helpers ==="
+	@sudo install -m 0755 src/fenris/monitor.py $(LIBEXEC_DIR)/fenris-monitor
+	@sudo install -m 0755 src/fenris/collect.py $(LIBEXEC_DIR)/fenris-collect
+	
+	@echo "=== Installing systemd units (dormant — not enabled/started) ==="
+	@sudo install -m 0644 units/fenris-collect.timer $(UNIT_DIR)/
+	@sudo install -m 0644 units/fenris-collect.service $(UNIT_DIR)/
+	@sudo systemctl daemon-reload
+	
+	@echo "=== Installing runit service files (dormant — not enabled) ==="
+	@sudo install -d -m 0755 /etc/sv/fenris-collect/log
+	@sudo install -m 0755 units/runit/fenris-collect/run /etc/sv/fenris-collect/run
+	@sudo install -m 0755 units/runit/fenris-collect/log/run /etc/sv/fenris-collect/log/run
+	@sudo touch /etc/sv/fenris-collect/down
+	
+	@echo "=== Installing polkit policy ==="
+	@sudo install -m 0644 polkit/com.bongbetic.fenris.monitor.policy $(POLKIT_DIR)/
+	
+	@echo "=== Recording manifest (IN-2, IN-10) ==="
+	@echo "# Fenris placement manifest — do not edit" | sudo tee $(MANIFEST) > /dev/null
+	@echo "# Generated by: sudo make install" | sudo tee -a $(MANIFEST) > /dev/null
+	@echo "# Timestamp: $$(date -u +%%Y-%%m-%%dT%%H:%%M:%%SZ)" | sudo tee -a $(MANIFEST) > /dev/null
+	@echo "$(BIN_DIR)/fenris" | sudo tee -a $(MANIFEST) > /dev/null
+	@echo "$(LIBEXEC_DIR)/fenris-monitor" | sudo tee -a $(MANIFEST) > /dev/null
+	@echo "$(LIBEXEC_DIR)/fenris-collect" | sudo tee -a $(MANIFEST) > /dev/null
+	@echo "$(UNIT_DIR)/fenris-collect.timer" | sudo tee -a $(MANIFEST) > /dev/null
+	@echo "$(UNIT_DIR)/fenris-collect.service" | sudo tee -a $(MANIFEST) > /dev/null
+	@echo "$(POLKIT_DIR)/com.bongbetic.fenris.monitor.policy" | sudo tee -a $(MANIFEST) > /dev/null
+	@echo "$(VENV_DIR)" | sudo tee -a $(MANIFEST) > /dev/null
+	@echo "$(DATA_DIR)" | sudo tee -a $(MANIFEST) > /dev/null
+	@echo "$(CONF_DIR)" | sudo tee -a $(MANIFEST) > /dev/null
+	@echo "$(MANIFEST)" | sudo tee -a $(MANIFEST) > /dev/null
+	
+	@echo "=== Install complete ==="
+	@echo "Units installed but NOT enabled or started (dormant — IN-3)."
+	@echo "To start monitoring: fenris monitor resume"
+	
+	@$(MAKE) --no-print-directory import-legacy
+
+# ─── Legacy import (IN-4, ST-7) ────────────────────────────────────────────
+
+import-legacy:
+	@if [ -f "$(LEGACY_HISTORY)" ]; then \
+		echo "=== Detected legacy history: $(LEGACY_HISTORY) ==="; \
+		echo "Running idempotent import..."; \
+		PYTHONPATH=$(VENDOR_DIR) $(PYTHON) -c "from fenris.legacy import import_legacy_history; from fenris.store import init_store; from pathlib import Path; conn = init_store(Path('$(DATA_DIR)/observations.db')); r = import_legacy_history(conn, Path('$(LEGACY_HISTORY)')); conn.close(); print(f'  Samples imported: {r.get(\"samples_imported\", 0)}'); print(f'  Hours imported: {r.get(\"hours_imported\", 0)}'); print(f'  Malformed lines: {r.get(\"malformed_lines\", 0)}') if not r.get('skipped') else print('  Skipped: already imported')" || echo "  Warning: import failed (non-fatal)"; \
+	else \
+		echo "=== No legacy history found at $(LEGACY_HISTORY) ==="; \
+	fi
+
+# ─── Upgrade ────────────────────────────────────────────────────────────────
+
+upgrade: dist/fenris-*.whl
+	@echo "=== Upgrading Fenris ==="
+	@echo "=== Snapshotting database (IN-6) ==="
+	@sudo cp $(DATA_DIR)/observations.db $(DATA_DIR)/observations.db.bak 2>/dev/null || true
+	
+	@echo "=== Installing new version-neutral runtime packages ==="
+	@sudo rm -rf $(VENDOR_DIR)
+	@sudo install -d -m 0755 $(VENDOR_DIR)
+	@sudo $(PYTHON) -m pip install --disable-pip-version-check --no-compile --target $(VENDOR_DIR) -r requirements.txt dist/fenris-*.whl --quiet
+	
+	@echo "=== Syncing units against manifest ==="
+	@sudo install -m 0644 units/fenris-collect.timer $(UNIT_DIR)/
+	@sudo install -m 0644 units/fenris-collect.service $(UNIT_DIR)/
+	@sudo install -d -m 0755 /etc/sv/fenris-collect/log
+	@sudo install -m 0755 units/runit/fenris-collect/run /etc/sv/fenris-collect/run
+	@sudo install -m 0755 units/runit/fenris-collect/log/run /etc/sv/fenris-collect/log/run
+	@sudo install -m 0644 polkit/com.bongbetic.fenris.monitor.policy $(POLKIT_DIR)/
+	@sudo install -m 0755 scripts/fenris $(BIN_DIR)/fenris
+	@sudo install -m 0755 src/fenris/monitor.py $(LIBEXEC_DIR)/fenris-monitor
+	@sudo install -m 0755 src/fenris/collect.py $(LIBEXEC_DIR)/fenris-collect
+	@sudo systemctl daemon-reload
+	
+	@echo "=== Updating manifest ==="
+	@echo "# Fenris placement manifest — do not edit" | sudo tee $(MANIFEST) > /dev/null
+	@echo "# Generated by: sudo make upgrade" | sudo tee -a $(MANIFEST) > /dev/null
+	@echo "# Timestamp: $$(date -u +%%Y-%%m-%%dT%%H:%%M:%%SZ)" | sudo tee -a $(MANIFEST) > /dev/null
+	@echo "$(BIN_DIR)/fenris" | sudo tee -a $(MANIFEST) > /dev/null
+	@echo "$(LIBEXEC_DIR)/fenris-monitor" | sudo tee -a $(MANIFEST) > /dev/null
+	@echo "$(LIBEXEC_DIR)/fenris-collect" | sudo tee -a $(MANIFEST) > /dev/null
+	@echo "$(UNIT_DIR)/fenris-collect.timer" | sudo tee -a $(MANIFEST) > /dev/null
+	@echo "$(UNIT_DIR)/fenris-collect.service" | sudo tee -a $(MANIFEST) > /dev/null
+	@echo "$(POLKIT_DIR)/com.bongbetic.fenris.monitor.policy" | sudo tee -a $(MANIFEST) > /dev/null
+	@echo "$(VENV_DIR)" | sudo tee -a $(MANIFEST) > /dev/null
+	@echo "$(DATA_DIR)" | sudo tee -a $(MANIFEST) > /dev/null
+	@echo "$(CONF_DIR)" | sudo tee -a $(MANIFEST) > /dev/null
+	@echo "$(MANIFEST)" | sudo tee -a $(MANIFEST) > /dev/null
+	
+	@echo "=== Restarting timer only if contents changed and active (IN-5) ==="
+	@for unit in fenris-collect.timer fenris-collect.service; do \
+		TMPFILE=$$(mktemp); \
+		sudo systemctl cat $$unit > $$TMPFILE 2>/dev/null || true; \
+		if ! diff -q $$TMPFILE $(UNIT_DIR)/$$unit > /dev/null 2>&1; then \
+			if systemctl is-active --quiet $$unit; then \
+				echo "  $$unit changed and active — restarting"; \
+				sudo systemctl restart $$unit; \
+			fi; \
+		fi; \
+		rm -f $$TMPFILE; \
+	done
+	
+	@echo "=== Applying forward-only schema migrations (IN-5, IN-6) ==="
+	@sudo env PYTHONPATH=$(VENDOR_DIR) $(PYTHON) -c "from fenris.store import migrate_to_latest; from pathlib import Path; n = migrate_to_latest(Path('$(DATA_DIR)/observations.db')); print(f'  Migration steps applied: {n}') if n else print('  Schema already current')"
+	
+	@echo "=== Upgrade complete ==="
+
+# ─── Uninstall (IN-7) ──────────────────────────────────────────────────────
+
+uninstall:
+	@echo "=== Uninstalling Fenris ==="
+	
+	@if [ -x $(LIBEXEC_DIR)/fenris-monitor ]; then \
+		echo "=== Performing sanctioned disable (§10.4) ==="; \
+		sudo $(LIBEXEC_DIR)/fenris-monitor disable --now || true; \
+	fi
+	
+	@echo "=== Stopping units ==="
+	@sudo systemctl stop fenris-collect.timer 2>/dev/null || true
+	@sudo systemctl disable fenris-collect.timer 2>/dev/null || true
+	@sudo systemctl daemon-reload
+	@-sudo rm -f /var/service/fenris-collect 2>/dev/null || true
+	@-sudo rm -rf /etc/sv/fenris-collect 2>/dev/null || true
+	@-sudo rm -rf /var/log/fenris-collect 2>/dev/null || true
+	
+	@echo "=== Removing installed files (preserving config and store) ==="
+	@-rm -f $(BIN_DIR)/fenris
+	@-rm -f $(LIBEXEC_DIR)/fenris-monitor
+	@-rm -f $(LIBEXEC_DIR)/fenris-collect
+	@-rmdir $(LIBEXEC_DIR) 2>/dev/null || true
+	@-rm -f $(UNIT_DIR)/fenris-collect.timer
+	@-rm -f $(UNIT_DIR)/fenris-collect.service
+	@-rm -f $(POLKIT_DIR)/com.bongbetic.fenris.monitor.policy
+	@sudo rm -rf $(VENV_DIR)
+	@-sudo rm -f $(MANIFEST)
+	
+	@echo "=== Uninstall complete ==="
+	@echo "Config preserved at $(CONF_DIR)"
+	@echo "Store preserved at $(DATA_DIR)"
+
+# ─── Purge ──────────────────────────────────────────────────────────────────
+
+purge: uninstall
+	@echo "=== Purging Fenris ==="
+	@-sudo rm -rf $(CONF_DIR)
+	@-sudo rm -rf $(DATA_DIR)
+	@echo "=== Purge complete ==="
+
+# ─── Test ───────────────────────────────────────────────────────────────────
+
+test:
+	$(PYTHON) -m pytest tests/ -v
+
+# ─── Lint ───────────────────────────────────────────────────────────────────
+
+lint:
+	$(PYTHON) -m ruff check src/ tests/
+
+# ─── Dependencies (IN-8) ───────────────────────────────────────────────────
+
+update-deps:
+	$(PYTHON) -m pip compile pyproject.toml -o requirements.txt
+
+# ─── Packaging (spec §3, §4, §5) ────────────────────────────────────────────
+
+# Version is sourced from pyproject.toml for both formats
+FENRIS_VERSION := $(shell sed -n 's/^version = "\(.*\)"/\1/p' pyproject.toml)
+
+# GPG signing — packaging key UID (spec §4)
+PACKAGING_KEY ?= packaging@bongbetic.com
+
+stage:
+	@echo "=== Staging packaging tree (v$(FENRIS_VERSION)) ==="
+	$(PYTHON) -m pip wheel --no-deps --wheel-dir dist .
+	bash packaging/stage.sh "$(FENRIS_VERSION)"
+
+package-deb: stage
+	@echo "=== Building deb package ==="
+	VERSION="$(FENRIS_VERSION)" nfpm pkg -f packaging/nfpm.yaml -p deb -t dist/
+	@echo "=== deb package built: dist/fenris_$(FENRIS_VERSION)_amd64.deb ==="
+
+package-rpm: stage
+	@echo "=== Building rpm package ==="
+	VERSION="$(FENRIS_VERSION)" nfpm pkg -f packaging/nfpm.yaml -p rpm -t dist/
+	@echo "=== rpm package built: dist/fenris-$(FENRIS_VERSION)-1.x86_64.rpm ==="
+
+package: package-deb package-rpm
+	@echo "=== Both packages built in dist/ ==="
+
+# ─── XBPS packaging (ADR 0008) ─────────────────────────────────────────────
+
+# XBPS signing key (separate from SSH authentication key)
+XBPS_SIGNING_KEY ?= $(HOME)/.ssh/id_xbps
+
+package-xbps: stage
+	@echo "=== Building XBPS package ==="
+	xbps-create -A x86_64 \
+		-n fenris-$(FENRIS_VERSION)_1 \
+		-s "Fenris NVMe wear monitor" \
+		-S "NVMe wear monitor with persistent TUI" \
+		-m "Fenris Packaging <packaging@bongbetic.com>" \
+		-H "https://git.bongbetic.com/xavierk/Fenris" \
+		-l "MIT" \
+		build/stage
+	@echo "=== XBPS package built: fenris-$(FENRIS_VERSION)_1.x86_64.xbps ==="
+
+sign-xbps: package-xbps
+	@echo "=== Signing XBPS package ==="
+	xbps-rindex --sign-pkg --privkey $(XBPS_SIGNING_KEY) \
+		fenris-$(FENRIS_VERSION)_1.x86_64.xbps
+	@echo "=== XBPS package signed ==="
+
+xbps-publish:
+	bash scripts/xbps-publish.sh --publish
+
+xbps-publish-dry-run:
+	bash scripts/xbps-publish.sh --dry-run
+
+# ─── GPG key management ─────────────────────────────────────────────────────
+
+generate-test-key:
+	@echo "=== Generating throwaway test GPG key ==="
+	@echo "This key is for CI/testing only — never use for real releases."
+	printf '%%no-protection\nKey-Type: RSA\nKey-Length: 3072\nName-Real: Fenris Packaging (TESTING ONLY)\nName-Email: packaging-test@bongbetic.com\nExpire-Date: 0\n%%commit\n' | \
+		gpg --batch --gen-key
+	@echo "=== Test key created. Fingerprint: ==="
+	@gpg --fingerprint packaging-test@bongbetic.com
+
+# ─── Signing ────────────────────────────────────────────────────────────────
+
+sign-rpm: package-rpm
+	@echo "=== Signing RPM payload ==="
+	@rpm --import packaging/keys/fenris-packaging.asc 2>/dev/null || true
+	rpmsign --addsign --define "_gpg_name $(PACKAGING_KEY)" \
+		dist/fenris-$(FENRIS_VERSION)-1.x86_64.rpm
+	@echo "=== RPM signed ==="
+	@rpm -Kv dist/fenris-$(FENRIS_VERSION)-1.x86_64.rpm
+
+checksums: package
+	@echo "=== Generating SHA256SUMS ==="
+	cd dist && sha256sum fenris_$(FENRIS_VERSION)_amd64.deb \
+		fenris-$(FENRIS_VERSION)-1.x86_64.rpm > SHA256SUMS
+	@echo "=== SHA256SUMS written ==="
+	@cat dist/SHA256SUMS
+
+clearsign: checksums
+	@echo "=== Clearsigning SHA256SUMS ==="
+	gpg --batch --yes --clearsign --local-user $(PACKAGING_KEY) \
+		dist/SHA256SUMS
+	@echo "=== SHA256SUMS.asc written ==="
+
+# ─── Release (spec §5) ──────────────────────────────────────────────────────
+
+release: package sign-rpm clearsign
+	@echo ""
+	@echo "=== Release v$(FENRIS_VERSION) ==="
+	@echo ""
+	@echo "Artifacts:"
+	@ls -la dist/fenris_$(FENRIS_VERSION)_amd64.deb \
+		dist/fenris-$(FENRIS_VERSION)-1.x86_64.rpm \
+		dist/SHA256SUMS.asc 2>/dev/null
+	@echo ""
+	@echo "Verify signing (manual):"
+	@echo "  rpm -Kv dist/fenris-$(FENRIS_VERSION)-1.x86_64.rpm"
+	@echo "  gpg --verify dist/SHA256SUMS.asc dist/SHA256SUMS"
+	@echo ""
+	@echo "Upload to registry:"
+	@echo "  curl -X PUT -u user:token -T dist/fenris_$(FENRIS_VERSION)_amd64.deb \\"
+	@echo "    'https://git.bongbetic.com/api/packages/xavierk/debian/pool/bookworm/main/upload'"
+	@echo "  curl -X PUT -u user:token -T dist/fenris_$(FENRIS_VERSION)_amd64.deb \\"
+	@echo "    'https://git.bongbetic.com/api/packages/xavierk/debian/pool/jammy/main/upload'"
+	@echo "  curl -X PUT -u user:token -T dist/fenris_$(FENRIS_VERSION)_amd64.deb \\"
+	@echo "    'https://git.bongbetic.com/api/packages/xavierk/debian/pool/noble/main/upload'"
+	@echo "  curl -X PUT -u user:token -T dist/fenris-$(FENRIS_VERSION)-1.x86_64.rpm \\"
+	@echo "    'https://git.bongbetic.com/api/packages/xavierk/rpm/fenris/upload'"
+	@echo ""
+	@echo "Create Gitea release with notes and attach:"
+	@echo "  dist/fenris_$(FENRIS_VERSION)_amd64.deb"
+	@echo "  dist/fenris-$(FENRIS_VERSION)-1.x86_64.rpm"
+	@echo "  dist/SHA256SUMS.asc"
+	@echo ""
+	@echo "Key ceremony: delete the private key after upload."
+	@echo "  See docs/install/signing-key-ceremony.md"
+
+# ─── Automated release flow (issue #52) ──────────────────────────────────────
+
+release-run:
+	bash scripts/release.sh --publish
+
+release-dry-run:
+	bash scripts/release.sh --dry-run
+
+clean:
+	@echo "=== Cleaning build artifacts ==="
+	rm -rf build/stage dist/fenris-*.deb dist/fenris-*.rpm dist/SHA256SUMS*

README.md

@@ -1,157 +1,239 @@
-<p align="center">
-  <picture>
-    <source srcset="assets/bongbetic-brand/wordmark-light.png" media="(prefers-color-scheme: dark)">
-    <img src="assets/bongbetic-brand/wordmark-dark.png" alt="Bongbetic" width="260">
-  </picture>
-  <br>
-  <sub>crafted with stubborn curiosity by <a href="https://bongbetic.com">Bongbetic</a></sub>
-</p>
+# Fenris 🐺
 
-<p align="center">
-  <img src="assets/bongbetic-brand/b_glyph.svg" width="48" alt="Fenris glyph">
-</p>
+*Observes an NVMe drive's real-world use and translates that history into an understandable endurance outlook.*
 
-<h1 align="center">Fenris 🐺 — Your SSD's Tell-All Diary</h1>
-
-<p align="center">
-  <em>Your NVMe drive has been keeping secrets. Fenris makes it confess — in real time.</em>
-  <br>
-  <em>How much did you write today? How long until it taps out? No fairy dust — just your actual bytes.</em>
-</p>
+Fenris is a persistent TUI monitor backed by a short-lived privileged collector on a systemd timer. It reads SMART data every few minutes, stores compact observation history in SQLite, and recomputes a usage-adjusted theoretical lifespan on every screen render — no fairy dust, just your actual bytes.
 
 ---
 
-Fenris is a tiny, stubborn daemon that eavesdrops on your NVMe drive's SMART gossip, writes it down every few minutes, and serves you a live dashboard that actually means something. Not "vibes" — **real GB written in the last 24 hours, real GB/hour, and a real countdown in hours, days, and years until your drive's endurance runs out**.
+## Requirements
 
-> Think of it as a Fitbit for your SSD. Except it doesn't nag you to drink water.
+- **Python ≥ 3.10** (verified at install time)
+- **smartmontools** (`smartctl` — verified at install time)
+- **systemd** with a polkit agent (the collector runs as root oneshot; elevation is exclusively polkit)
 
-## What it actually does (no hand-waving)
+No other OS packages or Python dependencies beyond [Textual](https://textual.textualize.io/) (pinned in the lockfile).
 
-- **Listens** — polls `smartctl -j` on your NVMe device (default every 5 minutes, you pick).
-- **Remembers** — appends every sample to `data/history.jsonl` and rolls up per-hour totals into `data/hourly.jsonl` (survives restarts, rebuilds itself if you yank the power).
-- **Calculates** — rolling 24-hour window: *exact* bytes written in the last 24h, GB/h, GB/day, implied total TBW from `percentage_used`, remaining TB, and a projected life-remaining breakdown. Warming-up badge until it has 24h of coverage — no fake confidence.
-- **Shows off** — dense, live dashboard with wear-over-time + trailing-24h per-hour bars, sticky header, live countdown, and stale warnings if the daemon dozes off.
+## Install from package (recommended)
 
-## You need
+### Debian / Ubuntu (apt)
 
-- **Python 3.7+**
-- **smartmontools** (`smartctl`)
-- Root-ish access to read NVMe SMART (passwordless `smartctl` or just run with `sudo` — your call)
+The Gitea instance Debian registry signs metadata with its own key. Verify the
+instance key fingerprint (TOFU hardening):
 
-### The sudo dance (one time)
+```text
+Fingerprint: <print after first release — paste beside the curl one-liner>
+```
 
-Fenris runs `sudo -n smartctl ...` so it doesn't get stuck asking for a password mid-nap:
+Add the instance key and repository:
 
 ```bash
-sudo visudo
-# add this line (swap in your username):
-youruser ALL=(root) NOPASSWD: /usr/sbin/smartctl
+sudo mkdir -p /etc/apt/keyrings
+sudo curl -fsSL -o /etc/apt/keyrings/gitea-xavierk.asc \
+  https://git.bongbetic.com/api/packages/xavierk/debian/repository.key
+
+echo "deb [signed-by=/etc/apt/keyrings/gitea-xavierk.asc] \
+  https://git.bongbetic.com/api/packages/xavierk/debian bookworm main" \
+  | sudo tee /etc/apt/sources.list.d/fenris.list
+
+sudo apt update && sudo apt install fenris
 ```
 
-No sudo? Run the whole thing with `sudo` and it'll still behave.
+Replace `bookworm` with your distribution codename (`bookworm`, `jammy`, or
+`noble`).
 
-## Get it running — 30 seconds
+### Fedora / openSUSE Tumbleweed (RPM)
 
-### The cozy way
+Use the Fenris-owned repo file (not Gitea's auto-generated one):
 
 ```bash
-./fenris.sh
-# pick 1) Start monitoring → choose device / interval / port → done
+sudo dnf config-manager --add-repo \
+  https://git.bongbetic.com/xavierk/Fenris/raw/branch/main/packaging/fenris.repo
+
+sudo dnf install fenris
 ```
 
-### The no-nonsense way
+On openSUSE Tumbleweed, add the same standard RPM repository file and install
+with zypper:
 
 ```bash
-python3 fenris.py start                          # defaults: /dev/nvme0, every 300s, port 8420
-python3 fenris.py start --interval 60 --port 9000  # if you're impatient
-python3 fenris.py status                         # "are we live? how's the drive?"
-python3 fenris.py sample                         # one sneaky sample right now
-python3 fenris.py stop                           # tuck it back in
+sudo zypper addrepo --refresh \
+  https://git.bongbetic.com/xavierk/Fenris/raw/branch/main/packaging/fenris.repo fenris
+sudo zypper install fenris
 ```
 
-Dashboard lives at **http://localhost:8420** (or whatever port you chose).
+The repo file sets `gpgcheck=1` against the Fenris packaging key (downloaded
+from the raw URL in `gpgkey`) and `repo_gpgcheck=0` (metadata check left to
+TLS).
 
-## The menu, demystified
+### Package signature verification
 
-Run `./fenris.sh` and you'll get:
+The RPM payload is signed with the Fenris packaging key (RSA 3072).
+Verification happens automatically via dnf's `gpgcheck=1`. For manual
+verification of downloaded assets:
 
-```
- 1) Start monitoring (background daemon + dashboard)
- 2) Stop monitoring
- 3) Status / current wear stats
- 4) Take one sample right now
- 5) Open dashboard URL
- ---
- h) Help / how this works
- q) Exit (go touch grass)
+```bash
+rpm -Kv fenris-*.x86_64.rpm          # RPM payload signature
+gpg --verify SHA256SUMS.asc SHA256SUMS  # Clearsigned checksum manifest
+sha256sum -c SHA256SUMS                  # Checksum match
 ```
 
-## What Fenris jots down
+The packaging public key is published in-repo — no keyservers. See
+`packaging/keys/fenris-packaging.asc` and
+`docs/install/signing-key-ceremony.md` for key lifecycle details.
 
-| Field | What's the gossip? |
-|-------|---------------------|
-| `percentage_used` | The drive's own wear-o-meter (0–100%) |
-| `bytes_written` / `bytes_read` | Lifetime totals — the receipts |
-| `available_spare` | Spare blocks left (%) |
-| `media_errors` | Uncorrectable boo-boos |
-| `power_on_hours` | How long it's been awake |
-| `temperature_c` | Is it sweating? |
-| `critical_warning` | NVMe's panic flags |
+### Dormant install
 
-Hourly rollups also stash `bytes_written` per hour, `pct_start`/`pct_end`, and temp peaks — so the 24h math stays honest.
+A fresh package install is fully dormant. Units are present but disabled;
+nothing runs. The only opt-in is the sanctioned toggle:
 
-## The dashboard — what's on screen
+```bash
+fenris monitor resume    # enable timer + open first monitoring period
+fenris monitor pause     # close the period, disable timer
+```
 
-- **Hero card: Projected life remaining** — big, friendly `361 d 2 h` (plus `≈ 361 days · ≈ 8666 hours · ≈ 0.99 years`), backed by `~280 GB/day` and `~101 TB left of ~202 TB total` on the test box.
-- **Data written (24h)** — exact GB in the rolling window + coverage (`10.4h of 24h` until warmed up).
-- **Write rate** — GB/h and GB/day, live.
-- **Wear, spare, temp, errors, power-on** — the usual suspects, with progress bars and polite color-coding.
-- **Two charts, side by side:** wear over time + trailing-24h hourly write bars (with a cheeky "now" bar for the current partial hour).
-- **Live plumbing:** polling synced to your interval, ETag-cached, countdown to next sample, warming-up + stale banners, pauses when you hide the tab (saves your battery, you're welcome).
+## Development install (make install)
 
-**API for the tinkerers:** `GET /api/data` · `/api/hourly` · `/api/summary` · `/api/config` · `/api/status` — all JSON, all friendly.
+For contributors building from source:
+
+```bash
+sudo make install
+```
+
+This builds a wheel, installs its locked pure-Python runtime packages into
+`/opt/fenris/vendor`,
+and places helpers, units, and the polkit policy. Units are dormant by default.
+
+```bash
+sudo make upgrade    # re-sync wheel, units, schema
+make uninstall       # removes artifacts, preserves config and store
+make purge           # also removes /etc/fenris and /var/lib/fenris
+```
+
+## Upgrade
+
+### Package upgrade
+
+```bash
+sudo apt update && sudo apt upgrade fenris    # Debian/Ubuntu
+sudo dnf upgrade fenris                       # Fedora
+```
+
+### Development upgrade
+
+```bash
+sudo make upgrade
+```
+
+What it does:
+1. Snapshots `observations.db` to a one-generation backup (`.bak`).
+2. Replaces the locked runtime packages under `/opt/fenris/vendor`.
+3. Syncs units and polkit against the manifest; runs `daemon-reload`.
+4. Restarts the timer **only** if unit contents changed **and** it is active — a running collection run finishes on its mapped interpreter; the next run uses the new code.
+5. Applies forward-only schema migrations (the store directory is never rebuilt; automatic downgrade does not exist).
+
+Rollback: reinstall the previous version and restore `observations.db.bak`.
+
+## Migration from make install
+
+If Fenris was previously installed with `sudo make uninstall` first, then
+installed from the package, existing config, store, and group survive by path
+continuity. Over-installing the package over a `make install` is
+**forbidden** — stale units shadow vendor placement. See
+[docs/install/migrate-from-makeinstall.md](docs/install/migrate-from-makeinstall.md).
+
+## Uninstall and purge
+
+### Package removal
+
+```bash
+sudo apt remove fenris       # preserves config and store
+sudo apt purge fenris        # also removes config and store
+sudo dnf remove fenris       # preserves config and store
+```
+
+### Development removal
+
+```bash
+make uninstall     # removes artifacts, preserves config and observation history
+make purge         # also removes /etc/fenris and /var/lib/fenris
+```
+
+Uninstall performs the sanctioned disable first (`fenris-monitor disable --now`) — an open period closes `user_disabled` — then removes the runtime packages, helpers, units, polkit policy, and wrapper while keeping `/etc/fenris` and the observation store. Reinstalling resumes from the preserved store.
+
+## Cadence drop-ins
+
+The default collection cadence is **5 minutes** (`OnUnitInactiveSec=5min` in the timer unit). To change it, place a systemd drop-in:
+
+```bash
+sudo systemctl edit fenris-collect.timer
+# Add:
+# [Timer]
+# OnUnitInactiveSec=10min
+```
+
+No interval key exists in `/etc/fenris/fenris.conf`. Cadence is a systemd concern, not a Fenris configuration key.
+
+## CLI reference
+
+| Command | Behavior |
+|---|---|
+| `fenris` | Opens the TUI (no arguments). |
+| `fenris status` | Projection facts, enabled/active state, last collect outcome, journal hint on failure or staleness. Never auto-samples. |
+| `fenris sample` | On-demand collection via the privileged helper. Blocks until the run completes. |
+| `fenris monitor pause` | Sanctioned disable — asks for confirmation, then disables the timer and closes the monitoring period. |
+| `fenris monitor resume` | Sanctioned enable — enables the timer and opens a monitoring period. No confirmation. |
+| `fenris baseline set <json>` | CLI-side validation, then polkit-guarded persistence. |
+| `fenris baseline clear` | Remove the endurance baseline. |
+| `fenris import <path>` | Idempotent single-transaction legacy import. |
+| `fenris start` / `stop` / `run` | Rejected with a one-line migration pointer — never aliased. |
+| `fenris --device` | Rejected with a pointer to the configuration file. |
+
+## Reading the dashboard
+
+`fenris` opens the TUI dashboard.
+
+- **Continuity** — the service strip's continuity line (and `fenris status`) reports whether monitoring survives reboots: `monitoring: active in background · persists across reboots`, or `monitoring: does not start on next boot`.
+- **Paused vs. quit** — a full-width `monitoring: paused — deliberate disable` block means collection is stopped (`fenris monitor pause`); resume with `fenris monitor resume`. Pressing `q` only leaves the screen — monitoring keeps running in the background.
+- **Auth banner** — at launch, `privileged actions will prompt for authentication (polkit)` shows once and clears on the first refresh. Privileged actions elevate via polkit; Fenris never asks for sudo.
+
+Per-release notes live on the [releases page](https://git.bongbetic.com/xavierk/Fenris/releases): each entry is the version's `CHANGELOG.md` section — what was added, changed, and fixed — plus standing install and verification instructions.
+
+## Retired menu options
+
+The legacy `fenris.sh` menu script and the `fenris.py` monolith have been removed. Here's where the old options went:
+
+| Legacy option | Successor |
+|---|---|
+| 1) Start monitoring | `fenris monitor resume` |
+| 2) Stop monitoring | `fenris monitor pause` |
+| 3) Status / current wear stats | `fenris status` |
+| 4) Take one sample right now | `fenris sample` |
+| 5) Open dashboard URL | Removed — the HTML dashboard and HTTP server are gone; the TUI is the primary interface. |
+
+## Configuration
+
+`/etc/fenris/fenris.conf` holds exactly one key — the device selector:
+
+```
+device = /dev/disk/by-id/nvme-Samsung_SSD_980_PRO_2TB_S6BENS0Txxxxx
+```
+
+Use a stable `/dev/disk/by-id/` path. Raw `/dev/nvmeX` paths are warned against. The file is re-read every collection run.
 
 ## Where's my stuff?
 
-```
-fenris/
-├── fenris.py                          # the whole show — daemon + server + math
-├── fenris.sh                          # the cozy menu
-├── README.md                          # hi — you're here
-├── assets/bongbetic-brand/            # Bongbetic wordmarks & glyphs (for Gitea + dashboard)
-└── data/
-    ├── history.jsonl                  # raw samples (JSONL, append-only)
-    ├── hourly.jsonl                   # per-hour rollups (auto-rebuilt on restart)
-    ├── fenris.pid                     # daemon PID
-    └── fenris.log                     # daemon chatter
-```
-
-## CLI cheat sheet
-
-```bash
-python3 fenris.py start  [--device /dev/nvme0] [--interval 300] [--port 8420]
-python3 fenris.py stop
-python3 fenris.py status
-python3 fenris.py sample [--device /dev/nvme0]
-python3 fenris.py run    # foreground mode — what `start` spawns internally
-```
-
-## Oops — troubleshooting without the tears
-
-**"smartctl not found"**
-```bash
-sudo apt install smartmontools    # Debian/Ubuntu
-sudo pacman -S smartmontools      # Arch — you already knew
-```
-
-**"needs root" / permission denied**
-Set up the passwordless line above, or just `sudo ./fenris.sh`.
-
-**Dashboard says "stale"**
-Daemon napped or crashed. `python3 fenris.py status` will tell you. Kick it again with `start`.
-
-**Only 10 hours of data and it says "preliminary"?**
-That's honesty, not a bug. It needs 24h of real writes to give a tight estimate. Let it simmer — the number gets sharper every hour.
+| Artifact | Package install | make install |
+|---|---|---|
+| Wrapper | `/usr/bin/fenris` | `/usr/local/bin/fenris` |
+| Helpers | `/usr/libexec/fenris/` | `/usr/libexec/fenris/` |
+| Units | `/usr/lib/systemd/system/` (vendor) | `/etc/systemd/system/` |
+| Polkit policy | `/usr/share/polkit-1/actions/` | `/usr/share/polkit-1/actions/` |
+| sysusers/tmpfiles | `/usr/lib/{sysusers,tmpfiles}.d/fenris.conf` | managed by Makefile |
+| Configuration | `/etc/fenris/fenris.conf` | `/etc/fenris/fenris.conf` |
+| Observation store | `/var/lib/fenris/observations.db` | `/var/lib/fenris/observations.db` |
+| Runtime packages | `/opt/fenris/vendor` | `/opt/fenris/vendor` |
+| Legacy history | — | `./data/history.jsonl` (auto-imported) |
 
 ---
 

docs/adr/0001-observation-store-sqlite.md

@@ -0,0 +1,46 @@
+# 1. Observation store: a single SQLite database
+
+## Status
+
+Accepted — resolves [Define the persistent observation store and legacy migration](https://git.bongbetic.com/xavierk/Fenris/issues/2) on the [Wayfinder map](https://git.bongbetic.com/xavierk/Fenris/issues/1).
+
+Amended by [Define endurance-baseline provenance and validation](https://git.bongbetic.com/xavierk/Fenris/issues/12): the `endurance_baseline` field set and validation contract — derived verification, entry-time unprivileged sysfs validation, and read-time controller-segment applicability.
+
+Amended by [Decide controller-segment metadata columns](https://git.bongbetic.com/xavierk/Fenris/issues/14): the `controller_segments` metadata snapshot — normalized identity diagnostics plus `vid`/`ssvid`/`transport` and a degraded flag, frozen at segment open, all nullable.
+
+## Context
+
+Fenris today persists full SMART samples to an append-only `data/history.jsonl` beside a derived `data/hourly.jsonl`, both in the checkout, with no schema versioning and silent skipping of malformed lines. The redesign replaces the HTML dashboard with a keyboard-first TUI backed by a short-lived privileged collector on a systemd timer and an unprivileged TUI ([lifecycle research](https://git.bongbetic.com/xavierk/Fenris/src/branch/research/systemd-privilege-lifecycle/docs/research/systemd-privilege-lifecycle.md)), and projects a usage-adjusted theoretical lifespan from Data Units Written over wall-clock time with categorical confidence ([endurance research](https://git.bongbetic.com/xavierk/Fenris/src/branch/research/nvme-endurance-signals/docs/research/nvme-endurance-signals.md)). The store must support a root writer appearing every few minutes while an unprivileged reader queries concurrently, must migrate the legacy observation history idempotently and interruption-safely, and must version its schema.
+
+## Decision
+
+1. **Substrate**: one SQLite database in WAL mode at `/var/lib/fenris/observations.db`. WAL gives the unprivileged reader a consistent snapshot while the collector writes; migration and schema changes are single transactions.
+2. **Access**: the database is root-owned and group-readable through the `fenris` read group created by packaging; the TUI opens it read-only. No `/run` snapshot or export layer.
+3. **Entities**:
+    - `samples` — recent raw SMART samples: timestamp, controller identity, raw `data_units_written`/`data_units_read` integers, `percentage_used`, `available_spare`, `media_errors`, `power_on_hours`, `power_cycles`, `unsafe_shutdowns`, temperature, `critical_warning`.
+    - `hour_observations` — one row per UTC hour: the usage-habit split (`seconds_active`, `seconds_idle`, `seconds_powered_off`, `seconds_unknown`), DUW/DUR deltas, temperature min/avg/max, sample count, coverage flag. Classification thresholds belong to the projection model, not the store.
+    - `day_aggregates` — one row per UTC day; the habit-evidence grain.
+    - `monitoring_periods` — `started_at`, `ended_at` (NULL = open), `end_cause` enum (`user_disabled`, `migrated`, …). Powered-off time stays inside a period; deliberately disabled time does not.
+    - `controller_segments` — boundaries where controller identity changes or DUW decreases; write deltas are never computed across a segment. Each row carries a metadata snapshot frozen when the segment opens and immutable thereafter ([Decide controller-segment metadata columns](https://git.bongbetic.com/xavierk/Fenris/issues/14)): normalized `subnqn`, `sn`, `mn`, `fr`, plus `vid`, `ssvid`, `transport`, and an `identity_degraded` flag — human diagnostics, never key components (`cntlid` excluded: it distinguishes controllers within one subsystem, out of scope for a single-drive monitor). `fr` may go stale after a mid-segment firmware update; counter discontinuities belong to the DUW-monotonic axis. Every metadata column is nullable — legacy-imported segments carry `mn` with NULLs, degraded segments whatever was observed — so incompleteness stays explicit.
+    - `endurance_baseline` — one active row, replaced on edit ([Define endurance-baseline provenance and validation](https://git.bongbetic.com/xavierk/Fenris/issues/12)): the rated-TBW value in bytes (`E_rated = entered_TBW × 10¹²`) plus mandatory provenance — source URL, document revision, entry date, model string, nominal capacity — and frozen validation facts (detected model, detected capacity bytes, `validated_by` `machine`/`user`, `validated_at`). Verification is derived at read — complete provenance and a drive match (machine or attested), never a stored boolean; incomplete provenance stores only behind an explicit unverified acknowledgment, as NULL fields in that precedence tier. Entry validation is an unprivileged live sysfs read of the configured device (normalized model containment with an interactive confirm recorded as `validated_by = user`; capacity within ±1%); at projection time applicability is a model match against the current controller segment, and a mismatch is retained — never auto-deleted — leaving the projection Unavailable.
+    - Projections are not stored; they are recomputed on read. There is no separate latest-status table.
+4. **Day boundary**: UTC, matching hours, so day derivation from hour rows is monotonic and DST-ambiguous or 23/25-hour days never exist in the store.
+5. **Retention**: raw samples are kept 14 days and pruned opportunistically by the collector; hour observations and day aggregates are retained indefinitely.
+6. **Migration** (first new-version collection run):
+    1. If the database already carries the legacy-import marker, do nothing.
+    2. `history.jsonl` is the sole authority: import raw samples, derive hour observations and day aggregates from them, and ignore `hourly.jsonl` as derived data (diff and log mismatches; do not trust).
+    3. One implicit `monitoring_periods` row opens at the first legacy sample and closes with `end_cause = migrated` at the migration moment. Pre-migration hours carry an unknown activity split except directly evidenced facts (samples present ⇒ powered on; DUW deltas ⇒ writes occurred).
+    4. The import is a single transaction: interruption leaves the database fully pre- or post-migration.
+    5. Only after commit are legacy files renamed to `*.migrated` (never deleted).
+    6. Malformed legacy lines are quarantined with a logged count, never silently dropped.
+7. **Projection inputs**: the `endurance_baseline` table lives in the database and is edited via the CLI; `/etc/fenris/` holds only operational configuration.
+8. **Versioning**: `PRAGMA user_version` plus ordered migration steps in code, each in its own transaction; the collector refuses to run against an unknown newer version.
+9. **Collector health**: not stored. Failures go to the journal (per the lifecycle decision); the freshest sample timestamp is the store's own staleness signal.
+
+## Consequences
+
+- Backups and state migration are copying one file (plus its WAL sidecars).
+- SQLite becomes a runtime dependency of both the collector and the TUI (Python `sqlite3` stdlib suffices; no server).
+- The collector's prune, import, and version steps are all transactional, so a killed timer run cannot leave partial state.
+- Legacy checkout-relative `data/` files stop being authoritative at migration; the migration ticket's rename-after-commit rule keeps them as a recovery trail.
+- The active/idle/powered-off classification contract with the projection model is the `hour_observations` column set, keeping storage and model decisions separable.

docs/adr/0002-projection-model-sustained-regime.md

@@ -0,0 +1,52 @@
+# 2. Projection model: sustained-regime rate with categorical confidence
+
+## Status
+
+Accepted — resolves [Define the lifespan projection and confidence model](https://git.bongbetic.com/xavierk/Fenris/issues/4) on the [Wayfinder map](https://git.bongbetic.com/xavierk/Fenris/issues/1).
+
+Amended by [Decide how degraded identity affects projection confidence](https://git.bongbetic.com/xavierk/Fenris/issues/15): a blank (degraded) identity key caps confidence at Limited evidence, and identity-change semantics extend verbatim to blank keys.
+
+## Context
+
+Fenris's current `compute_summary` projects from a single trailing-24-hour write rate against endurance inferred as `DUW / Percentage Used` or synthesized as `capacity × 600`, alongside a second linear regression of Percentage Used toward 100. The [endurance research](https://git.bongbetic.com/xavierk/Fenris/src/branch/research/nvme-endurance-signals/docs/research/nvme-endurance-signals.md) established which signals can defensibly support a projection, and [ADR 0001](0001-observation-store-sqlite.md) fixed the observation store while leaving classification thresholds and every projection rule to this model. This decision defines the algorithm and the user-facing contract the TUI consumes.
+
+## Decision
+
+1. **One projection.** The usage-adjusted theoretical lifespan is computed once, against the endurance baseline chosen by precedence (verified rated TBW → unverified manual override → Percentage-Used-implied → projection unavailable). Percentage Used is context, never a second projection: it renders as a vendor wear line, and when the wear it implies disagrees with the observed write rate by more than a factor of 2, a note says so. The current PU-slope regression (`wear_days`) and the `capacity × 600` synthesis are dropped.
+2. **Headline rate from the sustained regime.**
+    ```text
+    rate          = regime DUW delta bytes / in-period wall-clock seconds
+    projected     = max(E_baseline − W_t, 0) / rate      (rate > 0)
+    E_rated       = entered_TBW × 10¹² bytes
+    E_implied     = 100 · W_t / p                          (1 ≤ p ≤ 254)
+    ```
+    The default regime is the full observation history capped at 90 days. The 7-, 28-, and 90-day rates are computed independently of the regime and shown as a **scenario range**; only horizons the history actually covers appear (no placeholders).
+3. **Habit change.** A change is declared when the trailing 7-day mean of daily written bytes stays ≥ 2× (or ≤ 0.5×) the mean of the preceding 28 days for 3 consecutive days. The new regime starts at the first day of divergence and is adopted automatically, labeled "usage habit changed N days ago"; the scenario range keeps the longer horizons visible. A regime younger than 7 days caps projection confidence at Limited evidence.
+4. **Hour classification** (named constants, no configuration surface):
+    - **Powered-off**: the hour's power-on-hours delta is below 90% of its wall-clock span.
+    - **Active**: DUW delta ≥ 256 MiB in the hour.
+    - **Idle**: powered on, sampled, below the active threshold.
+    - **Unknown**: everything else — unsampled without power-on-hours evidence (machine-off and collector failure are indistinguishable), or inconsistent counters.
+    - Disabled time is not an hour state: it is wall-clock outside monitoring periods.
+5. **Denominator.** Wall-clock seconds inside monitoring periods, including powered-off and unknown time. Disabled periods are excluded from numerator and denominator. Unexplained gaps inside a period keep the aggregate counter delta, remain in the denominator as unknown seconds, and reduce coverage.
+6. **Minimum evidence.** Warming up until there are 14 distinct UTC day aggregates of which at most 2 fall below 50% coverage. The projection still renders while warming up, labeled with its facts. Unavailable conditions (no baseline, unsupported DUW, zero rate over the regime, identity change) render no lifespan number.
+7. **Staleness.** A newest day aggregate older than 48 hours drops confidence one level (Supported → Limited) and is shown as a contributing fact.
+8. **Confidence rule table.**
+    - **Unavailable**: no applicable baseline; DUW unsupported; zero rate over the regime; controller-identity change.
+    - **Supported**: verified baseline **and** ≥ 14 qualifying days **and** coverage ≥ 80% **and** fresh (< 48 h) **and** 7/28/90 rates within a factor of 2 across existing horizons **and** no single day ≥ 50% of trailing 28-day bytes **and** regime ≥ 7 days old **and** the current controller segment's identity key is not degraded.
+    - **Limited**: every other case with a baseline and a positive rate; the failing facts are shown.
+    - **Degraded identity** ([Decide how degraded identity affects projection confidence](https://git.bongbetic.com/xavierk/Fenris/issues/15)): a controller segment whose identity key is blank — every rung of the key ladder empty — is identity-degraded. Supported is unreachable while the current segment is degraded, because a blank key cannot detect a replacement; the fact "controller identity unavailable — replacement detection relies on write-counter continuity only" renders with every state, and the cap combines idempotently with the staleness drop (both land at Limited). Ephemeral markers (model "Linux", non-pcie transport) are segment metadata, never confidence facts.
+    - Confidence always renders as state plus contributing facts, never a percentage.
+9. **Segment breaks.** A DUW decrease with unchanged controller identity quarantines nothing: prior day aggregates remain habit evidence and the projection is Unavailable only until the new segment re-warms. A controller-identity change quarantines prior history from projection entirely — it describes a different drive. Degraded keys get no special casing ([Decide how degraded identity affects projection confidence](https://git.bongbetic.com/xavierk/Fenris/issues/15)): a blank-key segment is marked identity-degraded and segmented by DUW monotonicity alone, any visible change of the recorded key — including to or from blank — is a controller-identity change and quarantines, and equal blank keys continue the segment. Since even a degraded→healthy transition quarantines, the projection window only ever spans segments sharing one key, so a degraded current segment needs no cross-segment propagation rule.
+10. **Implied-baseline eligibility.** The Percentage-Used-implied baseline is computed only after ≥ 2 Percentage Used increments within the current controller segment; until then the projection is Unavailable with "vendor wear estimate too coarse to imply endurance".
+11. **Uncertainty.** The scenario range is the only spread shown; no statistical confidence interval appears anywhere. Zero rate → "no finite projection from this history", never infinity or zero.
+12. **Language.** The endurance research's required wording and six disclosures are adopted verbatim as the specification's language section.
+13. **Contract.** The projection function hands the TUI: the confidence state, the contributing facts — including the degraded-identity fact when the current segment's key is blank — the headline remaining time when one exists, the scenario range, the Percentage-Used context line, and the disclosure text. Projections are recomputed on read, never stored.
+
+## Consequences
+
+- The TUI information-architecture prototype (its ticket) consumes a fixed contract rather than inventing presentation states.
+- `compute_summary`'s wear-slope regression and capacity-synthesized endurance disappear; migration must not synthesize baselines for legacy history.
+- Coverage becomes a first-class displayed fact rather than an internal heuristic.
+- All guardrail thresholds live as documented constants in one projection module; tuning demand, if it ever appears, is a future decision rather than a config surface.
+- Two follow-on decisions surfaced and are ticketed separately: the controller-identity key that segments history, and endurance-baseline provenance validation.

docs/adr/0003-service-lifecycle-and-sanctioned-toggle.md

@@ -0,0 +1,33 @@
+# 3. Service lifecycle: timer-driven collection with a sanctioned control path
+
+## Status
+
+Accepted — resolves [Define the collector, service, and CLI lifecycle](https://git.bongbetic.com/xavierk/Fenris/issues/8) on the [Wayfinder map](https://git.bongbetic.com/xavierk/Fenris/issues/1). Amends the toggle mechanism of [Verify systemd lifecycle and privilege constraints](https://git.bongbetic.com/xavierk/Fenris/issues/7); its spirit — scoped, explicit, authenticated, no generic `manage-unit-files` grant — is intact.
+
+Amended by [Define endurance-baseline provenance and validation](https://git.bongbetic.com/xavierk/Fenris/issues/12): the helper gains a `baseline` verb that persists the CLI-validated endurance-baseline row — same fixed-operation, polkit-mediated pattern.
+
+## Context
+
+Fenris's current single process combines daemonization, a PID file, an HTTP dashboard, and control (`fenris.py start/stop/status/sample`) over checkout-relative state. [ADR 0001](0001-observation-store-sqlite.md) fixed the observation store, including `monitoring_periods` whose `user_disabled` end cause records deliberate pauses, and the [systemd lifecycle research](https://git.bongbetic.com/xavierk/Fenris/src/branch/research/systemd-privilege-lifecycle/docs/research/systemd-privilege-lifecycle.md) fixed the timer + oneshot architecture, standard paths, journal diagnostics, allow-listed status reads, and polkit-mediated startup toggles — while leaving cadence mechanics, the configuration surface, CLI compatibility, staleness thresholds, and the mechanism that records a deliberate disable open. In particular, `systemctl enable`/`disable` cannot write a monitoring-period row, so a direct-systemctl toggle cannot satisfy the store's semantics.
+
+## Decision
+
+1. **Units.** Two system units only: `fenris-collect.timer` (`WantedBy=timers.target`) and `fenris-collect.service` (`Type=oneshot`, root, `ExecStart=/usr/libexec/fenris/fenris-collect`; no listener, no UI code). The TUI and CLI are ordinary unprivileged processes and never units. There is no `/run/fenris` coordination surface: systemd serializes runs, the observation store holds state, and failures go to the journal per [ADR 0001](0001-observation-store-sqlite.md).
+2. **Cadence.** Default five minutes: `OnBootSec=2min`, `OnUnitInactiveSec=5min` (measured from run completion; drift accepted because hours are the evidence grain), `AccuracySec=30s`, `Persistent=no`, no suspend catch-up (absent hours classify through power-on-hours evidence), `TimeoutStartSec=90s` so a hung interrogation fails visibly. Cadence changes are documented drop-ins on the timer unit (`systemctl edit` + daemon-reload); no interval key exists in configuration.
+3. **Configuration.** `/etc/fenris/fenris.conf` holds exactly one key: the device selector, a stable `/dev/disk/by-id/…` path (raw nodes accepted with an instability warning), validated at collection time. The oneshot re-reads it every run, so there is no reload path to design. An invalid selector is a bounded failed run — journal plus failed unit result, retried next interval; `status` and the TUI also read the world-readable file directly and surface a `configuration error: <reason>` fact.
+4. **Entry points.** Two privileged binaries: `/usr/libexec/fenris/fenris-collect` (device interrogation and store writes; the unit's `ExecStart`) and `/usr/libexec/fenris/fenris-monitor` (fixed operations `enable` and `disable` with optional `--now`, plus the collect trigger, monitoring-period bookkeeping, and `baseline set`/`baseline clear` persistence for the CLI-validated endurance baseline; the only binary the polkit policy authorizes). One unprivileged `fenris` for humans: no arguments opens the TUI; subcommands (`status`, `sample`, `monitor pause`, `monitor resume`) are the CLI.
+5. **Sanctioned toggle.** Pause = `disable --now`; Resume = `enable --now`; both executed by `fenris-monitor`, which performs the systemctl operation and the monitoring-period bookkeeping in one step, under polkit action `com.bongbetic.fenris.monitor` (`auth_admin`, covering the collect trigger too). Root invokes the helpers directly; where no polkit agent exists the operation fails cleanly and prints the root equivalent. This amends the research's direct-systemctl toggle: a period boundary cannot be recorded by systemctl, so the toggle must be Fenris's own fixed operation.
+6. **Period rows.** Idempotent matrix: a first-ever enable opens a period at the enable moment (hours before the first successful sample are unknown-but-inside, correctly so when the device errors); a resume with an open period — a raw `systemctl stop` intervened — changes no row, the gap remaining inside as unknown seconds; a resume with no open period opens a new row at the resume moment; a pause with an open period closes it `user_disabled` at the pause moment; a pause otherwise is a no-op. A raw stop or disable outside the helper is an unexplained gap, never `user_disabled`: only the sanctioned path can record intent.
+7. **On-demand collection.** `fenris sample` and the TUI's collect-now route through `fenris-monitor` → `systemctl start fenris-collect.service`, which blocks until the oneshot exits, and the outcome (freshness line or journal hint) is reported synchronously. No code path outside `fenris-collect` touches the device; the TUI never samples in-process; no confirmation is required.
+8. **TUI controls.** Pause asks for confirmation; Resume does not (benign — friction invites raw-systemctl escapes). Boot enablement and current runtime activity are always displayed as separate facts, next to last collect outcome and freshness. No bare start/stop exists anywhere.
+9. **CLI compatibility.** `status` is a pure read-only composition of the observation store and allow-listed `systemctl show` properties: projection facts, enabled/active, last collect outcome, and a `journalctl -u fenris-collect.service` hint on failure or staleness; it never auto-samples and never prompts. `sample` is retained via the helper path; `--device` is rejected with a pointer to the configuration file. `start`, `stop`, and `run` are rejected with one-line migration pointers, not aliased — an alias would silently change meaning. `fenris.sh` is retired: not shipped, removed from the repository, and the README maps its five menu options to their successors.
+10. **Freshness constants.** Documented once, consumed by TUI and CLI alike: fresh means the newest sample is within 2× cadence + `AccuracySec` + 60 s; between that and 48 h the store is missed (a contributing fact); at ≥ 48 h it is stale, matching [ADR 0002](0002-projection-model-sustained-regime.md)'s evidence gate; an empty store reads "no observations yet" with an enable hint.
+
+## Consequences
+
+- Polkit ships one Fenris-specific policy authorizing exactly one fixed-operation binary; the collector itself is never polkit-reachable.
+- Monitoring-period boundaries are exact at toggle moments; approximation never enters the habit record.
+- Interval tuning is a systemd drop-in documented in the README; `/etc/fenris` stays a one-key file.
+- Headless administration has full parity: every TUI action has a CLI twin.
+- The TUI must run privileged operations through a terminal-attached subprocess so the platform polkit agent can prompt; the TUI prototype ticket validates this in practice.
+- Nothing survives of the prototype's daemonization, PID files, or HTTP server; their commands fail with pointers instead of quiet behavior changes.

docs/adr/0004-install-upgrade-removal-lifecycle.md

@@ -0,0 +1,31 @@
+# 4. Installation lifecycle: Makefile-delivered venv, dormant install, sanctioned teardown
+
+## Status
+
+Accepted — resolves [Define installation, upgrade, and removal behavior](https://git.bongbetic.com/xavierk/Fenris/issues/9) on the [Wayfinder map](https://git.bongbetic.com/xavierk/Fenris/issues/1). Amended by [ADR 0007](0007-package-delivery-amends-0004.md): package delivery replaces `make install` as primary; layout/ownership and maintainer-script mechanics per 0007. Runtime semantics (dormant install, polkit-only elevation, snapshot + forward-only migration, one-generation rollback) unchanged.
+
+## Context
+
+Fenris runs today from the source checkout (`fenris.py`, `fenris.sh`, `data/`): code, state, and control all live relative to wherever the checkout sits. The redesign fixes system artifacts — helpers in `/usr/libexec/fenris` ([ADR 0003](0003-service-lifecycle-and-sanctioned-toggle.md)), the observation store at `/var/lib/fenris/observations.db` ([ADR 0001](0001-observation-store-sqlite.md)), configuration at `/etc/fenris/fenris.conf` ([ADR 0003](0003-service-lifecycle-and-sanctioned-toggle.md)), Textual on Python 3.9+ ([framework decision](https://git.bongbetic.com/xavierk/Fenris/issues/6)) — but nothing says how those artifacts are delivered, upgraded, or removed, or what happens when the checkout moves or disappears.
+
+## Decision
+
+1. **Delivery.** `sudo make install` builds a wheel from the checkout and installs it, with pinned dependencies, into a dedicated Fenris-owned venv at `/opt/fenris`; a `/usr/local/bin/fenris` wrapper makes the unprivileged TUI/CLI a PATH command. The checkout is build-time input only: after install, nothing references it.
+2. **Layout and manifest.** Units in `/etc/systemd/system` (`fenris-collect.{timer,service}`, [ADR 0003](0003-service-lifecycle-and-sanctioned-toggle.md)); helpers in `/usr/libexec/fenris`; polkit policy in `/usr/share/polkit-1/actions/`; configuration and observation store in their ADR-fixed locations. The installer records every file it places in an explicit manifest consumed by upgrade and uninstall.
+3. **Privilege.** One root installer (`sudo make install`); at runtime, elevation is exclusively polkit (`auth_admin`, `fenris-monitor` only, [ADR 0003](0003-service-lifecycle-and-sanctioned-toggle.md)). The installer never enables or starts units.
+4. **Dormant install.** A fresh install is fully dormant: units present but disabled, nothing running, no monitoring period. The only opt-in is the sanctioned toggle (`fenris monitor resume [--now]`, or the first-run TUI prompt), which enables the timer and opens the first period in one step.
+5. **Legacy import.** The installer detects `./data/history.jsonl` beside the source (or accepts an explicit path), runs [ADR 0001](0001-observation-store-sqlite.md)'s idempotent single-transaction import, and reports imported counts — existing observations never depend on checkout survival. `fenris import <path>` remains available for later finds.
+6. **Upgrade.** `sudo make upgrade` builds and installs the new wheel into the same venv, syncs units and polkit against the manifest (`daemon-reload`; restart the timer only if unit contents changed and it is active — safe with `Persistent=no`), leaves timer state untouched, and never kills an in-flight collection run: a running oneshot finishes on its mapped interpreter, so at worst one old-code run completes to the store and the next run uses the new code. It then applies forward-only observation-store schema migrations governed by a `schema_version` table. `/var/lib/fenris` is never rebuilt.
+7. **Rollback.** Best-effort by design: before migrations run, the installer snapshots `observations.db` to a one-generation `observations.db.bak`; rollback means reinstalling the previous version and restoring the backup. Automatic schema downgrade is explicitly unsupported.
+8. **Removal.** `make uninstall` first performs the sanctioned disable (`fenris-monitor disable --now`) so an open monitoring period closes `user_disabled` — removal is deliberate, and only the sanctioned path records intent — then stops and disables the units and removes the venv, helpers, units, polkit policy, and wrapper, **keeping** `/etc/fenris` and the observation store. `make purge` additionally removes configuration and store. Journal entries age out naturally.
+9. **Dependencies.** Exact pins in a committed lockfile; install and upgrade both install from it. Refreshing pins is an explicit developer step (`make update-deps`, committed), never a side effect of installing.
+10. **Scaffolding and floor.** The installer creates `/var/lib/fenris` with [ADR 0001](0001-observation-store-sqlite.md)'s root-written group-read permissions and verifies `python3 ≥ 3.9`, failing cleanly otherwise — the Textual contingency becomes an install-time gate rather than a runtime crash. The database file itself is created lazily by the first write, so "no observations yet" remains a real state the TUI can greet.
+
+## Consequences
+
+- Installed Fenris survives checkout deletion; the checkout is only where builds happen.
+- Teardown preserves monitoring-period semantics: deliberate removal excludes the uninstalled span from the usage habit instead of leaving it as unknown-inside.
+- Installs are reproducible; dependency drift cannot ride in on an upgrade.
+- Reinstall after uninstall resumes from the preserved observation store; only purge erases history.
+- Rollback support is exactly one generation deep, no further.
+- The README documents install, upgrade, uninstall/purge, and legacy import alongside [ADR 0003](0003-service-lifecycle-and-sanctioned-toggle.md)'s menu-successor mapping.

docs/adr/0005-failure-detection-and-recovery.md

@@ -0,0 +1,27 @@
+# 5. Failure and recovery: visible degradation, never fabrication
+
+## Status
+
+Accepted — resolves [Define failure and recovery behavior](https://git.bongbetic.com/xavierk/Fenris/issues/10) on the [Wayfinder map](https://git.bongbetic.com/xavierk/Fenris/issues/1).
+
+## Context
+
+The observation store ([ADR 0001](0001-observation-store-sqlite.md)) and the service lifecycle ([ADR 0003](0003-service-lifecycle-and-sanctioned-toggle.md)) settled single-writer transactions, bounded single failed runs, freshness grading (fresh / missed / stale), and absent-hour classification through power-on-hours evidence. Left open by the [failure ticket](https://git.bongbetic.com/xavierk/Fenris/issues/10): behavior per failure class — malformed observations inside the store, missed observations, store faults (unreadable, corrupt, or newer-schema database), and repeated collector failures — and how the habit record re-anchors after the store itself is lost.
+
+## Decision
+
+1. **Malformed observations — refuse at the write boundary.** The collector validates every row it would write against the store's domain invariants (hour seconds sum to 3600, non-negative DUW delta within a controller segment, coverage consistent with sample count). A violating run writes nothing for that run, logs the refused row to the journal for post-mortem, and fails visibly — retried next interval. Readers (TUI, `status`) defensively exclude and count malformed rows as a contributing fact, but under a single trusted writer they should never see one. Store invariant: everything persisted is well-formed.
+2. **Missed observations — never backfill.** Fenris never interpolates, estimates, or fabricates an hour. Gaps remain unknown seconds; degradation flows exclusively through coverage, freshness facts, and confidence categories; recovery is the timer's next successful run. [ADR 0003](0003-service-lifecycle-and-sanctioned-toggle.md)'s power-on-hours classification is the only inference admitted.
+3. **Store faults — degrade, never recreate over.** An unreadable or corrupt database is a store fault: readers surface a "observation store unreadable" fact with the journal hint and show nothing else that depends on the store; the collector treats it as a bounded failed run and never recreates or overwrites an existing file. Recovery is human-sanctioned and documented: back up or move the corrupt file aside, the next run starts a fresh store, and if the legacy import never completed, the still-present `history.jsonl` is re-imported. No built-in destructive command exists.
+4. **Newer schema — readers refuse symmetrically.** The TUI and `status` detect a `user_version` newer than they understand and display "observation store written by a newer Fenris — upgrade Fenris" without partial interpretation, matching the collector's refusal in [ADR 0001](0001-observation-store-sqlite.md) and the forward-only upgrade rule of [ADR 0004](0004-install-upgrade-removal-lifecycle.md).
+5. **Repeated collector failures — flat cadence, no escalation.** The timer's retry is the recovery path; the settled freshness grading walks fresh → missed → stale as failures persist, so degradation is visible without new state. No backoff and no notification machinery; a persistent failure reads as stale exactly like any other gap.
+6. **Drive-reported anomalies — facts, not alerts.** `critical_warning`, media errors, and unsafe shutdowns surface as ordinary facts in the TUI and `status`; no alerting or notification surface exists. Fenris observes and projects; it does not alarm. The projection is unaffected: endurance math consumes writes, not warnings.
+7. **Orphaned samples — the collector re-anchors observed fact.** When a collection run finds no open monitoring period (fresh store after a store fault, completed legacy re-import, or first-ever run), it opens one at the run moment, never backdated. This records observed fact, not intent: only the sanctioned path of [ADR 0003](0003-service-lifecycle-and-sanctioned-toggle.md) records a `user_disabled` close. Coverage semantics stay intact without requiring a re-run of `fenris-monitor enable` after recovery.
+
+## Consequences
+
+- Validation lives at one boundary — the collector — so the store's contract is "everything in it is well-formed" and readers only defend against the impossible.
+- No synthetic data can ever enter the habit record; confidence categories can be trusted to reflect real evidence.
+- Store-fault recovery can lose history; the mitigation is the one-file backup story of [ADR 0001](0001-observation-store-sqlite.md), kept human-sanctioned so loss is never silent.
+- Period bookkeeping splits by epistemics: the helper records intent, the collector records observed fact.
+- Fenris stays fully local and silent: no notification, escalation, or alerting machinery anywhere.

docs/adr/0006-collector-acquisition-path.md

@@ -0,0 +1,28 @@
+# 6. Collector acquisition path: smartctl counters, sysfs identity
+
+## Status
+
+Accepted — resolves [Choose the collector's NVMe acquisition path](https://git.bongbetic.com/xavierk/Fenris/issues/16) on the [Wayfinder map](https://git.bongbetic.com/xavierk/Fenris/issues/1).
+
+## Context
+
+The collector ([ADR 0003](0003-service-lifecycle-and-sanctioned-toggle.md)) must acquire SMART/Health counters, thermal evidence, and controller identity each run. The [controller-identity research](https://git.bongbetic.com/xavierk/Fenris/src/branch/research/controller-identity/docs/research/controller-identity.md) fixed the identity key to the normalized, kernel-exposed subsystem NQN and warned that normalization must be specified once and applied at write time — or a collector implementation change can split a drive's own history. [ADR 0004](0004-install-upgrade-removal-lifecycle.md) pins exact Python dependencies in a dedicated venv, and the [segment-metadata decision](https://git.bongbetic.com/xavierk/Fenris/issues/14) froze nullable `vid`/`ssvid`/`transport` alongside the identity fields. Three first-party paths were candidates: the official libnvme Python bindings (SWIG; sysfs-backed attribute getters delivering normalized values), `nvme` CLI JSON output, and the incumbent `smartctl -j` plus sysfs reads.
+
+## Decision
+
+1. **Pin.** Every collection run acquires counters and thermal evidence solely from `smartctl -a -j <device>` and controller identity (`subnqn`, `sn`, `mn`, `fr`, `transport`) solely from sysfs (`/sys/class/nvme/<ctrl>/`). No other acquisition path exists anywhere in the codebase.
+2. **Hard pin, no fallback.** Any acquisition failure — missing binary, nonzero exit, malformed JSON, unreadable sysfs attribute — fails the whole collection run; [ADR 0005](0005-failure-detection-and-recovery.md)'s flat retry and freshness grading absorb the miss. A partial sample (identity without counters, or counters without identity) is never written: a transient read failure must not push a healthy drive down the degraded-identity path.
+3. **Normalization once, at write time.** One collector-side function normalizes every identity field: trailing spaces and newlines stripped, no case folding, empty-after-strip stored blank. `smartctl` counter and thermal fields are consumed as-is (smartmontools already trims the strings it copies). Padded and unpadded renderings of the same field therefore yield byte-identical stored values.
+4. **Segment metadata sourcing.** `transport` comes from the NVMe class sysfs directory; `vid`/`ssvid` from the PCI node (`/sys/class/nvme/<ctrl>/device/{vendor,subsystem_vendor}`) when present, null otherwise — metadata only, never key components.
+5. **Prerequisites.** `make install` verifies `smartctl` is present and fails cleanly otherwise. The acquisition path adds no Python dependency and no OS package beyond smartmontools; the [ADR 0004](0004-install-upgrade-removal-lifecycle.md) lockfile is untouched.
+
+## Considered options
+
+- **libnvme Python bindings** — the purest API and natively-normalized getters, but the SWIG module is not on PyPI: entering the venv requires the distro's `python3-libnvme` through `--system-site-packages` or a from-source build, coupling the exact-lockfile venv to the system Python and the distro's shipping choices. Rejected on dependency weight for one privileged five-minute oneshot.
+- **`nvme` CLI JSON** — one binary covers counters and identity, but it adds an OS package for what smartmontools already provides, emits untrimmed strings, and reports `subnqn` from Identify data rather than the kernel: when a controller reports an empty NQN the kernel synthesizes one for sysfs while `id-ctrl` JSON omits the field, so the identity ladder would drop a rung depending on the drive. Rejected on packaging and identity-key consistency.
+
+## Consequences
+
+- The venv stays pure-Python; the two acquisition channels per run (subprocess JSON plus sysfs reads) hide behind one acquisition function, gated by acceptance criteria AC-1–AC-5.
+- Identity is read from exactly the source the identity key names; libnvme's getters wrap the same sysfs attributes, so the values agree byte-for-byte where both exist.
+- Switching acquisition path later is history-sensitive: a future path must deliver byte-identical normalized identity values, or the change itself forces a controller-segment boundary.

docs/adr/0007-package-delivery-amends-0004.md

@@ -0,0 +1,34 @@
+# 7. Package delivery: native deb + rpm packages, amending the installation lifecycle
+
+## Status
+
+Accepted — resolves [Task: Compose release spec + ADR amending 0004](https://git.bongbetic.com/xavierk/Fenris/issues/42) on the [Wayfinder map](https://git.bongbetic.com/xavierk/Fenris/issues/33). This ADR **amends [ADR 0004](0004-install-upgrade-removal-lifecycle.md)** on delivery and file ownership only; every runtime semantic of 0004 — dormant install, polkit-only elevation, observation-store snapshot + forward-only migration, one-generation rollback — is inherited verbatim, restated below where the package delivery changes *who* performs it.
+
+## Context
+
+ADR 0004 fixed delivery as `sudo make install` from a source checkout: wheel into a Fenris-owned runtime directory at `/opt/fenris`, a hand-rolled placement manifest, units in `/etc/systemd/system`. The release plan ([map](https://git.bongbetic.com/xavierk/Fenris/issues/33), decisions [Lock channel + toolchain](https://git.bongbetic.com/xavierk/Fenris/issues/38), [Signing + key policy](https://git.bongbetic.com/xavierk/Fenris/issues/39), [Package ownership](https://git.bongbetic.com/xavierk/Fenris/issues/40), [Migration path](https://git.bongbetic.com/xavierk/Fenris/issues/41), [Release cadence](https://git.bongbetic.com/xavierk/Fenris/issues/43)) now ships Fenris as native deb + rpm packages built by nfpm and published to the self-hosted Gitea 1.27.1 package registry, for Debian 12, Ubuntu 22.04/24.04, Fedora 40+, and openSUSE Tumbleweed (x86_64), with locked pure-Python dependencies vendored at `/opt/fenris/vendor`. Packages become the primary delivery; ADR 0004's delivery model demotes to a dev fallback.
+
+The implementation-ready operative contracts live in the [release and packaging specification](../spec/release-packaging.md); this ADR records the decisions and their rationale.
+
+## Decision
+
+Amendments to ADR 0004, section by section:
+
+1. **Delivery (amended).** Packages are primary: one deb per codename pool (`bookworm`, `jammy`, `noble`) and one rpm (group `fenris`, Fedora 40+ and openSUSE Tumbleweed), built by nfpm from a single `packaging/nfpm.yaml` over locked pure-Python runtime packages staged at `/opt/fenris/vendor`, published to the Gitea Debian/RPM registry and installed with `apt`, `dnf`, or `zypper`. `sudo make install` remains as the dev fallback for machines without packages; the two deliveries are mutually exclusive per machine. Version scheme `<pyproject-version>-1`, revision bump on rebuild.
+2. **Layout and manifest (amended).** The hand-rolled manifest model is retired: the dpkg/rpm database **is** the manifest, and nothing like `manifest.txt` ships. Package-owned layout: units in `/usr/lib/systemd/system` (vendor placement; `/etc/systemd/system` is admin-only for drop-ins and enable state); helpers stay in `/usr/libexec/fenris` (exactly `fenris-monitor` and `fenris-collect` — no new polkit-reachable binaries); polkit policy in `/usr/share/polkit-1/actions/`; wrapper at `/usr/bin/fenris` (FHS; `/usr/local/bin` remains `make install`'s). The `fenris` group is declared in `/usr/lib/sysusers.d/fenris.conf` (`g fenris -`) and `/var/lib/fenris` in `/usr/lib/tmpfiles.d/fenris.conf` (`d /var/lib/fenris 2750 root fenris -`), both invoked from the maintainer scripts. The package owns the `/var/lib/fenris` directory only; `observations.db`, WAL sidecars, and `.bak` are never owned and never ghosted — ghost-erase would delete the store, violating 0004 §8.
+3. **Privilege (unchanged).** Root acts through maintainer scripts at install/upgrade/removal time; at runtime, elevation is exclusively polkit, exactly as 0004 §3 and [ADR 0003](0003-service-lifecycle-and-sanctioned-toggle.md) §5 fix it.
+4. **Dormant install (restated for packages).** A fresh package install is fully dormant: postinst/%post performs `systemctl daemon-reload` (plus `systemd-sysusers` and `systemd-tmpfiles --create`) and nothing else — never enable, never preset, never start; no preset file ships. The sanctioned toggle (`fenris monitor resume`) remains the only opt-in.
+5. **Legacy import (narrowed).** Auto-detection of `./data/history.jsonl` is scoped to `make install` only — a package install has no checkout to inspect. `fenris import <path>` remains available as the only import path from packages.
+6. **Upgrade (inherited, maintainer-script mechanics).** Upgrades arrive as packages from the single registry channel. postinst/%post on upgrade: snapshot `observations.db` → one-generation `.bak`, run forward-only schema migrations through the target `python3` with `/opt/fenris/vendor` on its import path (no new binaries), `daemon-reload`, and restart `fenris-collect.timer` only if unit contents changed **and** it is active. `/var/lib/fenris` is never rebuilt; a running oneshot finishes on its old interpreter.
+7. **Rollback (unchanged, plus one hard edge).** One-generation `.bak` semantics are unchanged. Package downgrade is additionally unsupported: forward-only store-version refusal means installing an older package over a newer store fails by design; documented rollback = restore the snapshot, then install the old release.
+8. **Removal (mapped).** deb `remove` ≈ `make uninstall` (conffile and store survive); deb `purge` ≈ `make purge` (plus `.bak` and group cleanup); rpm erase ≈ `make uninstall` (unmodified config removed, modified survives as `.rpmsave`; purge is a documented manual command). prerm/%preun performs the sanctioned disable — `fenris-monitor disable --now`, closing the period `user_disabled` — on remove/erase **only, never on upgrade** (deb prerm upgrade case is a no-op; rpm `%preun` gated on `$1 -eq 0`).
+9. **Conffile semantics (new).** `/etc/fenris/fenris.conf` ships as a placeholder-commented default with no active device selector — deb conffile, rpm `%config(noreplace)`. The device selector is entered by hand (root edits the file), as in both prior deliveries; no configuration verb is added to `fenris-monitor`, and [ADR 0003](0003-service-lifecycle-and-sanctioned-toggle.md) §3's read-and-validate-at-collection-time semantics are untouched. On upgrade, local edits survive as-is; a changed package default lands beside them as `.dpkg-new`/`.rpmnew`.
+10. **Migration from make-install systems (new).** Remove-then-install via runbook only — no migration script, no auto-clean. preinst/%pre aborts with a pointer to the runbook if make-install remnants are detected (`/var/lib/fenris/manifest.txt` or `/etc/systemd/system/fenris-collect.timer`). Store and config survive by path continuity; the migration resets the system to dormant and the user opts back in with `fenris monitor resume`.
+
+## Consequences
+
+- Package installs, upgrades, and removals carry dpkg/rpm-native semantics; nothing in Fenris's own tooling duplicates them.
+- The manifest was 0004's answer to "what did the installer place"; the package database answers it better, and uninstall-keeps-store now holds by package ownership rather than by manifest discipline.
+- `make install` and packages are mutually exclusive per machine; over-install is blocked, not repaired (stale `/etc` units would silently shadow vendor units).
+- Hand-edited configuration remains the model: the device selector is a root-edited file in every delivery, keeping the polkit surface at exactly one binary.
+- Release mechanics — channel, signing, cadence, rollback documentation — are fixed in the [release and packaging specification](../spec/release-packaging.md) and the tickets it cites; this ADR deliberately stops at lifecycle semantics.

docs/adr/0008-native-void-support.md

@@ -0,0 +1,21 @@
+# 8. Native Void Linux support and XBPS delivery
+
+Status: Accepted scope and hosting direction; implementation and acceptance proof pending.
+
+Fenris will support Void Linux natively with runit and full application feature parity, while retaining its existing Debian/RPM and systemd support. This extends the platform boundary in [ADR 0003](0003-service-lifecycle-and-sanctioned-toggle.md) and the delivery scope in [ADR 0007](0007-package-delivery-amends-0004.md): requiring Void users to replace their init system would not meet the native-support goal.
+
+Delivery will include a Fenris-maintained, signed XBPS repository that users configure once for subsequent installation and updates through XBPS, plus versioned release artifacts and notes on Gitea. All downloads must be served directly by Gitea itself; a separate static HTTP repository, even alongside Gitea, does not satisfy this requirement.
+
+Use a dedicated public Gitea repository, provisionally `xavierk/Fenris-xbps`, with a permanent `stable` branch. Its raw-file URL serves the XBPS index, versioned packages, and package signatures as ordinary Git blobs without LFS. Keeping binaries in a separate repository avoids increasing application source-clone size. This accepts growth in distribution-repository Git history in exchange for publishing index and artifacts together through one branch update, without the generic registry's delete-and-upload index replacement gap. The proposed repository has not yet been created.
+
+Serialize publication, commit the signed index and its new artifacts together, and retain older versioned artifacts in the current tree so clients with cached older indexes can still download them. Native XBPS installation and update tests against the actual endpoint are required before release validation. Verify binary delivery limits and index freshness: the inspected Gitea raw endpoint advertised six-hour HTTP caching, so immediate update visibility has not been established.
+
+Immediate availability is required: after successful XBPS publication, an explicit repository refresh against the permanent URL must discover the newly published version without a cache-expiry wait or a URL change. This does not promise automatic installation on client machines. Acceptance must exercise a client that fetched the previous index before publication and verify that refresh retrieves the new index and its signed package afterward. Resolve and document actual client and intermediary cache behavior; if the selected Gitea route cannot meet this requirement, hold XBPS publication and revisit its delivery mechanics rather than silently accepting delayed availability.
+
+Hosting evidence: [Gitea generic registry](https://docs.gitea.com/usage/packages/generic), [raw download routing](https://github.com/go-gitea/gitea/blob/main/routers/web/web.go), [download handler](https://github.com/go-gitea/gitea/blob/main/routers/web/repo/download.go), and [Void repository signing](https://docs.voidlinux.org/xbps/repositories/signing.html). Source inspection and an existing raw-file GET establish feasibility, not end-to-end XBPS validation.
+
+The first supported Void target is x86_64 with glibc, matching the inspected development machine. Release validation must cover installation, real collection, pause/resume, reboot persistence, upgrade, and removal on that machine, preserving existing observation history. Debian/RPM compatibility remains part of the acceptance scope. Additional architectures and musl support are outside this first release.
+
+Package formats have independent publication gates: publish each validated format, and hold only formats that have not passed release validation. A failure or pending validation in XBPS must not prevent a validated Debian or RPM package from shipping, and vice versa. Release notes must identify available formats and those still withheld; publication must not imply validation of a missing format.
+
+After successful native acceptance testing, leave the released XBPS package installed on this machine and monitoring the selected NVMe drive. Preserve the observation history collected during testing. Coordinate the reboot test with the user so it can occur at a suitable interruption point.

docs/agents/domain.md

@@ -0,0 +1,26 @@
+# Domain Docs
+
+How engineering skills should consume this repository’s domain documentation.
+
+## Layout
+
+This is a single-context repository:
+
+```text
+/
+├── CONTEXT.md
+├── docs/adr/
+└── ...
+```
+
+## Before exploring
+
+Read `CONTEXT.md` and relevant ADRs under `docs/adr/` when they exist. If they do not exist, proceed silently. Domain-modeling skills create them lazily when terminology or durable architectural decisions are resolved.
+
+## Use the glossary’s vocabulary
+
+Use terminology defined in `CONTEXT.md` consistently. If required terminology is missing or contradictory, raise it through domain modeling rather than silently inventing synonyms.
+
+## Flag ADR conflicts
+
+If proposed work contradicts an existing ADR, identify the conflict explicitly instead of silently overriding it.

docs/agents/issue-tracker.md

@@ -0,0 +1,85 @@
+# Issue tracker: Gitea
+
+Issues for this repository live in Gitea at:
+
+https://git.bongbetic.com/xavierk/Fenris/issues
+
+Use the authenticated `tea` CLI from the repository root. The configured login is `xavierk`.
+
+## General operations
+
+- List: `tea issues list`
+- Read: `tea issues <index> --comments`
+- Create: `tea issues create --title "<title>" --description "<body>"`
+- Edit: `tea issues edit <index> --title "<title>" --description "<body>"`
+- Assign: `tea issues edit <index> --add-assignees "<username>"`
+- Add labels: `tea issues edit <index> --add-labels "<labels>"`
+- Comment: `tea comments add <index> --description "<comment>"`
+- Close: `tea issues close <index>`
+- Reopen: `tea issues reopen <index>`
+
+Use `--output json` for machine-readable list and read operations. Use `tea api` when the high-level issue commands do not expose a native Gitea operation.
+
+## When a skill says “publish to the issue tracker”
+
+Create a Gitea issue in this repository. Preserve Markdown formatting in its body and apply any labels required by the invoking skill.
+
+## When a skill says “fetch the relevant ticket”
+
+Read the named issue with comments. The user may provide its URL, title, or index. In user-facing output, refer to issues by their linked titles rather than bare indices.
+
+## Wayfinding operations
+
+Wayfinder maps and decision tickets are Gitea issues.
+
+### Map and ticket grouping
+
+- A map has the label `wayfinder:map`.
+- Create one milestone named `Wayfinder: <map title>` for the effort.
+- Assign the map and all its tickets to that milestone.
+- Every ticket links its parent by name near the top: `Parent map: [<map title>](<map URL>)`.
+- Every ticket has exactly one type label: `wayfinder:research`, `wayfinder:prototype`, `wayfinder:grilling`, or `wayfinder:task`.
+
+The shared milestone and explicit parent link express the child relationship, because this Gitea version has no native parent/child issue API.
+
+### Blocking
+
+Use Gitea’s native issue-dependency relationship. To make `<blocked>` depend on `<blocker>`:
+
+```bash
+tea api -X POST \
+  repos/{owner}/{repo}/issues/<blocked>/dependencies \
+  -F index=<blocker> \
+  -f owner=xavierk \
+  -f repo=Fenris
+```
+
+List blockers:
+
+```bash
+tea api repos/{owner}/{repo}/issues/<index>/dependencies
+```
+
+Remove the relationship with the same payload and `-X DELETE`.
+
+### Frontier
+
+List open issues in the map’s milestone. Exclude:
+
+- the issue labelled `wayfinder:map`
+- assigned tickets, because assignment is the claim
+- tickets whose dependency query returns any open issue
+
+The remaining open, unassigned, unblocked tickets are the frontier. Choose the oldest first unless the user names one.
+
+### Claim
+
+Before doing any ticket work, assign it to the current `tea whoami` user. An open ticket without an assignee is unclaimed.
+
+### Resolve
+
+1. Add the answer as a resolution comment.
+2. Close the ticket.
+3. Re-fetch the map immediately before editing it.
+4. Append a linked one-line context pointer to `Decisions so far`.
+5. Create newly visible tickets, then wire dependencies in a second pass.

docs/install/migrate-from-makeinstall.md

@@ -0,0 +1,87 @@
+# Migrating from make-install to packages
+
+This runbook covers the transition from a `sudo make install` system to the native deb or rpm package. Packages are the primary delivery; `make install` remains as the dev fallback. The two deliveries are **mutually exclusive** per machine.
+
+## Why over-install is forbidden
+
+Installing a package over a make-install system silently breaks things:
+
+- **Stale admin units shadow vendor units.** `make install` places `fenris-collect.timer` and `fenris-collect.service` in `/etc/systemd/system/`. The package installs them in `/usr/lib/systemd/system/` (vendor placement). Systemd loads admin units first — the stale copy takes precedence, and the package update never reaches the running system.
+- **The local wrapper shadows the package wrapper.** `make install` places the `fenris` wrapper at `/usr/local/bin/fenris`. The package places it at `/usr/bin/fenris`. The shell finds `/usr/local/bin` first on PATH — the old checkout-relative wrapper runs instead of the package wrapper.
+
+Neither condition is reversible by reinstalling the package. The only safe path is remove-then-install.
+
+## Pre-migration checklist
+
+1. Confirm no monitoring period is actively running that you want to preserve across the gap:
+   ```
+   fenris status
+   ```
+   The migration resets the system to dormant (see [No-move continuity](#no-move-continuity) below). You opt back in with `fenris monitor resume`.
+
+2. If you have hand-edited configuration at `/etc/fenris/fenris.conf`, note it. The config survives the migration in place (see below).
+
+## Remove step
+
+```
+sudo make uninstall
+```
+
+This performs the **sanctioned disable** (`fenris-monitor disable --now`), closing the current monitoring period as `user_disabled`. It then removes all make-install artifacts: the venv at `/opt/fenris`, the wrapper at `/usr/local/bin/fenris`, the helpers at `/usr/libexec/fenris/`, the units in `/etc/systemd/system/`, and the polkit policy. The placement manifest at `/var/lib/fenris/manifest.txt` is removed.
+
+**What survives the remove:**
+
+- `/var/lib/fenris/observations.db` (and WAL sidecars, `.bak`) — the observation store
+- `/var/lib/fenris/` directory itself — root-written, group-read
+- `/etc/fenris/fenris.conf` — your hand-written configuration
+- The `fenris` system group — created by `groupadd -f` during make-install
+- Journal entries — age out naturally
+
+## Install step
+
+```
+sudo apt install fenris       # Debian/Ubuntu
+sudo dnf install fenris       # Fedora
+```
+
+The package installs into its own layout without touching the surviving store, config, or group.
+
+## No-move continuity
+
+These invariants are verified by the containerized acceptance tests (issue #50):
+
+| Asset | Make-install state | Package post-install | Mechanism |
+|---|---|---|---|
+| `fenris` group | Exists (`groupadd -f`) | Unchanged | `systemd-sysusers` is a no-op when the group already exists |
+| `/var/lib/fenris` directory | Exists (mode 2750, root:fenris) | Unchanged | `systemd-tmpfiles --create` is a no-op when the directory already exists |
+| `observations.db` + sidecars | Present from prior monitoring | Unchanged, never owned by the package | Package owns the directory only; store contents are never ghosted |
+| `/etc/fenris/fenris.conf` | Hand-edited device selector | Survives in place; package default lands as `.dpkg-new` / `.rpmnew` | dpkg conffile / rpm `%config(noreplace)` semantics |
+| Store schema | Version from prior Fenris release | Caught up by the upgrade-path migration | `postinst` / `%post` runs `migrate_to_latest()` on upgrade |
+
+The package detects the make-install system has been removed by the absence of the two markers:
+- `/var/lib/fenris/manifest.txt` (the placement manifest)
+- `/etc/systemd/system/fenris-collect.timer` (pre-manifest make installs)
+
+If either marker exists, the package installation aborts with a pointer to this runbook.
+
+## Reset-to-dormant
+
+`make uninstall`'s sanctioned disable closes the open monitoring period as `user_disabled`. After the package install, the system is dormant — the timer is installed but disabled, nothing is running, no monitoring period is open.
+
+To resume monitoring:
+
+```
+fenris monitor resume
+```
+
+This is the sanctioned opt-in. It enables the timer and opens the first monitoring period in one step. The migration costs at most one short sample gap (the interval between `make uninstall` and `fenris monitor resume`), honestly recorded in the endurance timeline.
+
+## Verification
+
+After migration, confirm the package is correctly installed:
+
+```
+fenris status
+```
+
+The status command should show the dormant state: timer disabled, no active monitoring period, and the observation store intact from the prior make-install system.

docs/install/signing-key-ceremony.md

@@ -0,0 +1,230 @@
+# Signing key ceremony
+
+The Fenris packaging key signs RPM payloads and clearsigns SHA256SUMS manifests.
+This document describes the key's lifecycle: creation, per-release use, rotation,
+and destruction.
+
+## Key specification
+
+| Property | Value |
+|---|---|
+| Algorithm | RSA 3072 |
+| UID | `Fenris Packaging <packaging@bongbetic.com>` |
+| Expiry | 2 years from creation |
+| Hierarchy | Single key — no master/subkey split (single maintainer, manual builds) |
+| Private key storage | Password manager only |
+| Public key storage | `packaging/keys/fenris-packaging.asc` in-repo, release notes, docs |
+| Keyservers | Never — TOFU-over-TLS via raw URL |
+
+## First release: key creation
+
+```bash
+# Generate the dedicated RSA-3072 packaging key
+gpg --batch --gen-key <<EOF
+%no-protection
+Key-Type: RSA
+Key-Length: 3072
+Name-Real: Fenris Packaging
+Name-Email: packaging@bongbetic.com
+Expire-Date: 2y
+%commit
+EOF
+
+# Export the public half — this file is committed to the repo
+gpg --armor --export packaging@bongbetic.com > packaging/keys/fenris-packaging.asc
+
+# Print the fingerprint for docs and release notes
+gpg --fingerprint packaging@bongbetic.com
+```
+
+Save the **private key** to the password manager immediately:
+
+```bash
+gpg --armor --export-secret-keys packaging@bongbetic.com
+```
+
+Then **delete the private key from the local keyring** — it must never persist
+on any build host:
+
+```bash
+gpg --delete-secret-keys packaging@bongbetic.com
+gpg --delete-keys packaging@bongbetic.com
+```
+
+The committed `fenris-packaging.asc` must contain the real public key (replace
+the placeholder comments).
+
+## Per-release signing flow
+
+Each release performs: **import → sign → delete**. The private key is never
+stored on disk longer than the release takes.
+
+### Step 1: Import the private key
+
+Retrieve the private key from the password manager and import it:
+
+```bash
+gpg --import /tmp/packaging-key-private.asc
+rm /f /tmp/packaging-key-private.asc   # Shred if possible
+```
+
+### Step 2: Build and sign packages
+
+The Makefile target `make release` handles signing automatically when the
+key is in the keyring:
+
+```bash
+make release    # builds, signs RPM, clearsigns SHA256SUMS, prints upload steps
+```
+
+Under the hood:
+
+1. `rpmsign --addsign` signs the RPM payload with the packaging key
+   (invoked by `make sign-rpm`).
+2. `sha256sum` generates the checksum manifest.
+3. `gpg --clearsign` produces `SHA256SUMS.asc` with the packaging key.
+
+### Step 3: Delete the private key
+
+Immediately after signing:
+
+```bash
+gpg --delete-secret-keys packaging@bongbetic.com
+gpg --delete-keys packaging@bongbetic.com
+```
+
+Verify the key is gone:
+
+```bash
+gpg --list-keys packaging@bongbetic.com
+# Should produce: gpg: keyblock resource ...: No such file or directory
+```
+
+The entire import → sign → delete cycle should take minutes. The private key
+must never be left in any keyring between releases.
+
+## Key rotation (outline)
+
+When the key approaches expiry, or if it is compromised:
+
+1. **Generate a new key** using the same procedure as first release.
+2. **Publish the new public key** alongside the old one in-repo:
+   ```text
+   packaging/keys/fenris-packaging.asc          # new key (primary)
+   packaging/keys/fenris-packaging-previous.asc  # old key (one cycle)
+   ```
+3. **Sign the next RPM** with the new key.
+4. **Update `fenris.repo`** to list both `gpgkey` URLs (dnf accepts multiple):
+   ```ini
+   gpgkey=https://git.bongbetic.com/xavierk/Fenris/raw/branch/main/packaging/keys/fenris-packaging.asc
+         https://git.bongbetic.com/xavierk/Fenris/raw/branch/main/packaging/keys/fenris-packaging-previous.asc
+   ```
+5. **Drop the old key** from the repo after one release cycle. Delete
+   `fenris-packaging-previous.asc` and revert `gpgkey` to the single URL.
+
+## Verification
+
+Consumers verify the RPM payload signature via dnf (gpgcheck=1 in
+`fenris.repo` points at the published public key). The SHA256SUMS manifest
+verification is manual for downloaded assets:
+
+```bash
+gpg --verify SHA256SUMS.asc SHA256SUMS
+sha256sum -c SHA256SUMS
+```
+
+## One-time live probe
+
+Before the first real release, verify the full registry path end-to-end with a
+throwaway package. This confirms apt/dnf metadata generation, signature
+verification, and consumer setup work as a real consumer would experience them.
+
+### Setup
+
+```bash
+# Create a throwaway package name to avoid polluting fenris metadata
+PROBE_NAME="fenris-regtest"
+PROBE_VERSION="0.0.1"
+```
+
+### Publish
+
+```bash
+# Build a throwaway deb and rpm (use the existing nfpm config with a dummy name)
+# Or use a pre-built package — the probe tests the registry path, not the build
+
+# Upload deb to all codename pools
+for CODENAME in bookworm jammy noble; do
+  curl --fail -X PUT \
+    -u "xavierk:${GITEA_TOKEN}" \
+    -T "dist/${PROBE_NAME}_${PROBE_VERSION}_amd64.deb" \
+    "https://git.bongbetic.com/api/packages/xavierk/debian/pool/${CODENAME}/main/upload"
+done
+
+# Upload rpm
+curl --fail -X PUT \
+  -u "xavierk:${GITEA_TOKEN}" \
+  -T "dist/${PROBE_NAME}-${PROBE_VERSION}-1.x86_64.rpm" \
+  "https://git.bongbetic.com/api/packages/xavierk/rpm/fenris/upload"
+```
+
+### Verify apt metadata (Debian/Ubuntu consumer perspective)
+
+```bash
+# On a Debian/Ubuntu machine:
+sudo mkdir -p /etc/apt/keyrings
+sudo curl -fsSL https://git.bongbetic.com/api/packages/xavierk/debian/repository.key \
+  | sudo gpg --dearmor -o /etc/apt/keyrings/gitea-xavierk.asc
+
+echo "deb [signed-by=/etc/apt/keyrings/gitea-xavierk.asc] https://git.bongbetic.com/api/packages/xavierk/debian bookworm main" \
+  | sudo tee /etc/apt/sources.list.d/fenris.list
+
+sudo apt update
+apt show ${PROBE_NAME}           # metadata present, correct version
+apt install --dry-run ${PROBE_NAME}  # dependency resolution works
+
+# Verify InRelease signature
+apt-key list 2>/dev/null || gpg --no-default-keyring --keyring /etc/apt/keyrings/gitea-xavierk.asc --list-keys
+```
+
+### Verify dnf metadata (Fedora consumer perspective)
+
+```bash
+# On a Fedora machine:
+sudo dnf config-manager --add-repo https://git.bongbetic.com/xavierk/Fenris/raw/branch/main/packaging/fenris.repo
+# Or use Gitea's auto-generated repo for the probe:
+sudo dnf config-manager --add-repo https://git.bongbetic.com/api/packages/xavierk/rpm/fenris.repo
+
+dnf info ${PROBE_NAME}          # metadata present, correct version
+dnf install --assumeno ${PROBE_NAME}  # dependency resolution works
+
+# Verify rpm signature
+rpm -q --scripts ${PROBE_NAME}  # no scripts (throwaway)
+```
+
+### Verify checksums and clearsign
+
+```bash
+# Download from release assets or local build
+gpg --verify SHA256SUMS.asc SHA256SUMS
+sha256sum -c SHA256SUMS
+```
+
+### Cleanup
+
+```bash
+# Delete the throwaway packages from the registry
+for CODENAME in bookworm jammy noble; do
+  curl --fail -X DELETE \
+    -u "xavierk:${GITEA_TOKEN}" \
+    "https://git.bongbetic.com/api/packages/xavierk/debian/pool/${CODENAME}/main/${PROBE_NAME}/${PROBE_VERSION}/amd64"
+done
+
+curl --fail -X DELETE \
+  -u "xavierk:${GITEA_TOKEN}" \
+  "https://git.bongbetic.com/api/packages/xavierk/rpm/fenris/${PROBE_NAME}/${PROBE_VERSION}/x86_64"
+
+# Remove test source list on consumer machines
+sudo rm /etc/apt/sources.list.d/fenris.list
+sudo apt update
+```

docs/research/deb-rpm-toolchain.md

@@ -0,0 +1,239 @@
+# Research: deb + rpm packaging toolchain for bundled-venv builds
+
+Issue: #34 (parent plan: #33) — branch `research/toolchain`
+Date: 2026-09-03 · target: Fenris 0.3.0, x86_64, Debian 12 / Ubuntu 22.04+24.04 / Fedora 40+
+
+## TL;DR
+
+**Recommended: nfpm** with a build script that stages a `--copies` venv at
+`/opt/fenris`. One `nfpm.yaml` is the single source of truth for both formats;
+`nfpm pkg -p deb && nfpm pkg -p rpm` (one invocation per format — `-p` takes a
+single string, verified in `internal/cmd/package.go`). Actively maintained
+(releases v2.47.0, 2026-06-20; repo pushed 2026-08-31). Runner-up: fpm (active,
+v1.18.0 gem 2026-08-26), but its "config" is a long CLI invocation per format —
+the single source of truth degrades into a shell script. dh-virtualenv is
+deb-only and its last upstream release is 2020-10 (effectively dormant);
+rpmbuild spec is rpm-only and cannot share file lists with a deb build without
+external generation.
+
+## Constraint evidence: distro textual is unusable (mostly)
+
+| Distro | python3-textual | Source |
+|---|---|---|
+| Debian 12 (bookworm) | **0.1.13-1** | https://packages.debian.org/bookworm/python3-textual |
+| Ubuntu 22.04 (jammy) | **0.1.13-1** | https://packages.ubuntu.com/jammy/python3-textual |
+| Ubuntu 24.04 (noble) | **0.1.13-1** | https://packages.ubuntu.com/noble/python3-textual |
+| Fedora 40 | 0.48.1 | https://src.fedoraproject.org/rpms/python-textual (f40 spec) |
+| Fedora 41 / 42 / 43 | 0.69.0 / 1.0.0 / 4.0.0 | same spec, f41–f43 branches |
+
+Fenris declares `textual>=0.40.0` (pyproject) but pins `textual==8.2.8`
+(requirements.txt). Debian 12 + Ubuntu 22.04/24.04 are ~1 major era behind even
+the *floor*; Fedora 40 technically meets `>=0.40` but not the pin. Verdict
+unchanged: **vendor deps inside the package for all targets**; per-format
+`depends:` only on `python3 (>= 3.9)`, `smartmontools`, `systemd`.
+
+## Tool-by-tool
+
+### 1. nfpm (goreleaser) — RECOMMENDED
+
+- **Route:** Makefile target builds staging tree → one `nfpm.yaml` →
+  `nfpm package -p deb` + `nfpm package -p rpm`. (Goreleaser release pipeline
+  can wrap both later.)
+- **Shared assets:** version, description, maintainer, `depends`,
+  `contents:` file list, `scripts:` all live once in `nfpm.yaml`; per-format
+  deltas via `overrides: { deb: ..., rpm: ... }` and `packager:`-scoped
+  content entries (https://nfpm.goreleaser.com/configuration/, source
+  `www/content/docs/configuration.md`).
+- **Prerequisites:** single static Go binary (`go install
+  github.com/goreleaser/nfpm/v2/cmd/nfpm@latest`, Homebrew, or release
+  tarball — https://nfpm.goreleaser.com/install/). No toolchain per distro,
+  no root, no containers required (build same tree for both formats).
+- **Venv → file list:** stage with `python3 -m venv --copies staging/opt/fenris
+  && staging/opt/fenris/bin/pip install dist/fenris-*.whl`; map in one entry:
+  `contents: [{ src: staging/opt/fenris/, dst: /opt/fenris, type: tree }]`.
+  Shebangs point at fixed absolute `/opt/fenris/bin/python` → no relocation
+  issues. `--copies` avoids symlink-to-/usr breakage. Config file →
+  `type: config|noreplace` (=%config(noreplace) on rpm, conffile semantics on
+  deb). `/var/lib/fenris` store → `type: ghost` (rpm: owned-but-not-packed;
+  deb: ignored → create in `postinstall` script instead).
+- **Systemd/polkit/libexec:** plain `contents:` entries —
+  `/usr/lib/systemd/system/fenris-collect.{service,timer}` (or
+  `/etc/systemd/system` to match current Makefile), polkit action at
+  `/usr/share/polkit-1/actions/`, helpers under `/usr/libexec/fenris/`.
+  `scripts:` supports `postinstall` (deb maintainer script / rpm scriptlet) —
+  run `systemctl daemon-reload`, create `/var/lib/fenris` root:fenris 2750,
+  group creation.
+- **Upgrade/removal:** deb — dpkg replaces all non-conffile files, conffile
+  prompts/preserves (`.dpkg-new`) per Debian Policy ch-files
+  (https://www.debian.org/doc/debian-policy/ch-files.html); removal keeps
+  conffiles + unowned store; purge cleans. rpm — `rpm -U` replaces,
+  `%config(noreplace)` keeps local edits as `.rpmnew`; only owned dirs are
+  removed on erase (nfpm `type: dir` exists precisely to claim ownership —
+  docs warn not to claim distro-owned dirs).
+- **Maintenance:** very active. goreleaser/nfpm, 2.6k stars, last push
+  2026-08-31, v2.47.0 released 2026-06-20 (GitHub API).
+
+### 2. fpm — viable, weaker single-source-of-truth
+
+- **Route:** staging tree (same as above) then
+  `fpm -s dir -t deb ... staging/=/ ; fpm -s dir -t rpm ...`.
+- **Shared assets:** none declarative — everything is CLI flags
+  (`-n`, `-v`, `--config-files`, `--deb-systemd`, `--directories`,
+  `--after-install`, `--rpm-posttrans`, …). Flag list:
+  https://fpm.readthedocs.io/en/latest/cli-reference.html. The two
+  invocations *will* drift unless wrapped in a Makefile that shares variables;
+  the "single source" is then a shell script, not a checked declarative file.
+  (`--deb-systemd` exists; no rpm-native unit macro — you hand it the unit
+  file plus `--rpm-posttrans` for daemon-reload.)
+- **Prerequisites:** Ruby + gem (`gem install fpm`) or distro package;
+  building rpm side needs `rpmbuild` present for some features.
+- **Venv → file list:** `-s dir` maps a directory into the package verbatim —
+  same staging-tree trick as nfpm. `--config-files /etc/fenris` marks
+  conffiles (deb) / %config (rpm).
+- **Upgrade/removal:** identical downstream semantics to nfpm (native dpkg/rpm
+  behavior); differences are only in how metadata/scripts land in the
+  package.
+- **Maintenance:** active — releases v1.16.0 (2024-12), v1.17.0 (2025-10),
+  v1.18.0 (2026-08-26); gem 1.18.0 on rubygems; ~11.5k stars. But docs are
+  openly "work in progress" (https://fpm.readthedocs.io/en/latest/).
+
+### 3. dh-virtualenv (Spotify) — deb-only, dorms
+
+- **Route:** debhelper add-on: `debian/rules` with
+  `dh $@ --with python-virtualenv --buildsystem=python_distutils`;
+  produces a .deb containing venv at `/opt/venvs/<package>`
+  (`DH_VIRTUALENV_INSTALL_ROOT` overridable, `--builtin-venv` for `python -m
+  venv`). Docs: repo `doc/usage.rst`, `doc/tutorial.rst`
+  (https://github.com/spotify/dh-virtualenv).
+- **Shared assets:** none with rpm — it cannot emit .rpm at all. Would still
+  need a second toolchain for Fedora → fails the criterion outright.
+- **Prerequisites:** `build-essential debhelper devscripts equivs` +
+  `dh-virtualenv` (tutorial.rst); Debian 12 still ships it as
+  `dh-virtualenv 1.2.2-1.3` (https://packages.debian.org/bookworm/dh-virtualenv).
+- **Venv → file list:** automatic — it builds the venv during the debhelper
+  sequence and rewrites shebangs; the .deb owns the whole venv tree. Least
+  manual work of all four, for deb alone.
+- **Upgrade/removal:** standard dpkg; whole venv tree is package-owned, so
+  `apt remove` deletes it cleanly; `--pypi-url`/requirements handled by tool.
+- **Maintenance:** last upstream release **1.2.2, 2020-10-22** (GitHub tag);
+  repo last pushed 2024-04-27, RTD docs 404. Effectively dormant upstream —
+  fine via Debian's own packaging, but risky as strategic dependency.
+- **Bonus fact:** PyPI `dh-virtualenv` project now returns 404 — install only
+  from Debian repo / git.
+
+### 4. rpmbuild spec + vendored venv — rpm-native, no deb
+
+- **Route:** hand-written `fenris.spec`: `%install` stage builds venv into
+  `%{buildroot}/opt/fenris`, `%files` lists it plus units/polkit/libexec,
+  `%ghost %attr(2750,root,fenris) /var/lib/fenris`, `%config(noreplace)` for
+  `/etc/fenris`, `systemd_post/preun` macros for the timer. Reference style:
+  https://docs.fedoraproject.org/en-US/packaging-guidelines/.
+- **Shared assets:** the spec is a second, parallel description of the same
+  file list — nothing is shared with any deb build without generating one
+  side from the other (e.g. generate spec + debian/control from a manifest).
+  Worst single-source-of-truth score.
+- **Prerequisites:** `rpm-build`, mock/koji for cleanroots; Fedora toolchain
+  knowledge; per-distro `Release:`/dist tag handling.
+- **Venv → file list:** `%files` line `%{buildroot}/opt/fenris/...` — venv
+  becomes ordinary payload; shebangs already absolute.
+- **Upgrade/removal:** canonical rpm semantics (same as above) plus real
+  systemd scriptlet macros — the *best-behaved* rpm integration of the four,
+  at the cost of hand-maintained spec.
+- **Maintenance:** rpmbuild itself is maintained forever (part of RPM), but
+  *your* spec is 100% hand-maintained duplication.
+
+## Comparison matrix
+
+| Criterion | nfpm | fpm | dh-virtualenv | rpmbuild spec |
+|---|---|---|---|---|
+| deb + rpm from one config | ✅ one YAML (2 invocations) | ⚠️ flags per invocation | ❌ deb only | ❌ rpm only |
+| File list shared across formats | ✅ `contents:` | ⚠️ per-invocation args | n/a | ❌ |
+| Vendored venv supported | ✅ staging `type: tree` | ✅ `-s dir` | ✅✅ automatic (deb) | ✅ `%files` |
+| conffile / %config(noreplace) | ✅ `type: config\|noreplace` | ✅ `--config-files` | ✅ (debhelper) | ✅ `%config(noreplace)` |
+| ghost store dir | ✅ `type: ghost` | ⚠️ `--rpm-ghost`? (no deb equiv) | ❌ | ✅ `%ghost` |
+| systemd scriptlets | ✅ `scripts:` + macros? (plain scripts) | ✅ `--deb-systemd`, `--rpm-posttrans` | ✅ (deb) | ✅✅ native macros |
+| Prereqs on build host | Go binary (or brew/apt tarball) | Ruby gem | debhelper stack | rpm-build + mock |
+| Maintenance (2026) | 🟢 active (v2.47.0) | 🟢 active (v1.18.0) | 🔴 dormant since 2020 (Debian carries it) | 🟢 tool yes / 🔴 your spec |
+| Risk | young-ish config schema churn | docs thin | dead upstream | duplication forever |
+
+## Proposed pipeline (sketch)
+
+```make
+# Makefile additions (build only — install target stays for source installs)
+stage: dist/fenris-*.whl
+	rm -rf build/stage
+	python3 -m venv --copies build/stage/opt/fenris
+	build/stage/opt/fenris/bin/pip install --no-compile dist/fenris-*.whl
+	install -D -m 0755 scripts/fenris build/stage/usr/bin/fenris
+	install -D -m 0755 src/fenris/monitor.py  build/stage/usr/libexec/fenris/fenris-monitor
+	install -D -m 0755 src/fenris/collect.py  build/stage/usr/libexec/fenris/fenris-collect
+	install -D -m 0644 units/fenris-collect.timer   build/stage/usr/lib/systemd/system/fenris-collect.timer
+	install -D -m 0644 units/fenris-collect.service build/stage/usr/lib/systemd/system/fenris-collect.service
+	install -D -m 0644 polkit/com.bongbetic.fenris.monitor.policy \
+		build/stage/usr/share/polkit-1/actions/com.bongbetic.fenris.monitor.policy
+
+package-deb package-rpm: stage
+	nfpm pkg -f packaging/nfpm.yaml -p deb -t dist/
+	nfpm pkg -f packaging/nfpm.yaml -p rpm -t dist/
+```
+
+```yaml
+# packaging/nfpm.yaml (excerpt)
+name: fenris
+arch: amd64
+platform: linux
+version: ${VERSION}          # env expansion, documented feature
+maintainer: Fenris Maintainers <ops@bongbetic.com>
+description: SMART drive observation daemon with persistent TUI
+homepage: https://git.bongbetic.com/xavierk/Fenris
+depends: [smartmontools]
+contents:
+  - src: build/stage/        # everything above
+    dst: /
+    type: tree
+  - dst: /etc/fenris         # config dir; ship fenris.conf as config|noreplace
+    type: dir
+  - src: packaging/fenris.conf
+    dst: /etc/fenris/fenris.conf
+    type: config|noreplace
+  - dst: /var/lib/fenris     # rpm: %ghost ownership; deb: create in postinst
+    type: ghost
+scripts:
+  postinstall: packaging/postinst.sh   # groupadd fenris; install -d -o root -g fenris -m 2750 /var/lib/fenris; systemctl daemon-reload (units shipped dormant)
+  preremove:  packaging/prerm.sh        # stop timer if running
+overrides:
+  deb:
+    depends: [python3 (>= 3.9), smartmontools]
+  rpm:
+    depends: [python3 >= 3.9, smartmontools]
+```
+
+## Recommendation
+
+Adopt **nfpm + staged `--copies` venv**: closest to single source of truth
+(one YAML for both formats), smallest prerequisite surface (one static binary),
+actively maintained, and every Fenris constraint (units, polkit, libexec,
+`/etc/fenris` conffile, `/var/lib/fenris` ghost/store) has a first-class
+mapping. Keep fpm as documented fallback (identical staging tree, works
+anywhere Ruby exists). Do not build the release pipeline on dh-virtualenv
+(dormant, deb-only) or on a hand-maintained spec file (duplication, deb side
+unaddressed).
+
+## Sources
+
+- nfpm config reference: https://nfpm.goreleaser.com/configuration/ (source:
+  goreleaser/nfpm `www/content/docs/configuration.md`, accessed 2026-09-03)
+- nfpm CLI (single `-p`): goreleaser/nfpm `internal/cmd/package.go`
+- nfpm releases/status: GitHub API, repo pushed 2026-08-31, v2.47.0 2026-06-20
+- fpm README + CLI reference: https://github.com/jordansissel/fpm,
+  https://fpm.readthedocs.io/en/latest/cli-reference.html; releases v1.18.0
+  (2026-08-26), gem 1.18.0
+- dh-virtualenv docs: `doc/usage.rst`, `doc/tutorial.rst` @ master; tag 1.2.2
+  dated 2020-10-22 (GitHub commits API); PyPI project 404;
+  Debian 12 package 1.2.2-1.3 (packages.debian.org)
+- Distro textual versions: packages.debian.org, packages.ubuntu.com,
+  src.fedoraproject.org `python-textual.spec` f40–f43
+- Upgrade semantics: Debian Policy ch-files
+  (https://www.debian.org/doc/debian-policy/ch-files.html); Fedora packaging
+  guidelines (https://docs.fedoraproject.org/en-US/packaging-guidelines/);
+  RPM directive behavior quoted in nfpm config docs (%ghost, %config(noreplace))

docs/research/gitea-package-registry.md

@@ -0,0 +1,116 @@
+# Research: Gitea 1.27 Debian + RPM package registry feasibility
+
+Issue: [Fenris deb + rpm release plan](https://git.bongbetic.com/xavierk/Fenris/issues/33) →
+[Research: Gitea 1.27 Debian + RPM package registry feasibility](https://git.bongbetic.com/xavierk/Fenris/issues/35)
+Verified 2026-09-03 against live instance `https://git.bongbetic.com` (reports `1.27.1` via `/api/v1/version`)
+and primary sources: docs.gitea.com 1.27 Debian/RPM registry pages and Gitea `v1.27.1` source (go-gitea/gitea tag).
+
+**Verdict: feasible.** Every publish/consume path tested live with throwaway packages `fenris-regtest` (all deleted afterward; package list verified empty).
+
+## 1. Publish paths (verified live, HTTP 201)
+
+### Debian (`.deb`)
+
+```bash
+curl --user xavierk:$TOKEN --upload-file fenris_0.3.0_amd64.deb \
+  "https://git.bongbetic.com/api/packages/xavierk/debian/pool/{distribution}/{component}/upload"
+```
+
+- `distribution` and `component` are free-form path segments chosen at upload time (e.g. `bookworm/main`, `noble/main`). Gitea derives apt suites from what was uploaded — verified: same .deb published to `pool/bookworm/main` and `pool/noble/main` (both 201), both then served in `dists/bookworm/` and `dists/noble/` with correct `Suite:`/`Codename:` headers.
+- Republish of identical name+version+distribution+component+architecture → **409 Conflict** (verified). Must delete first.
+
+### RPM (`.rpm`)
+
+```bash
+# no group (flat repo)
+curl --user xavierk:$TOKEN --upload-file fenris-0.3.0-1.el9.x86_64.rpm \
+  "https://git.bongbetic.com/api/packages/xavierk/rpm/upload"
+# with group (distro tag, nestable)
+curl --user xavierk:$TOKEN --upload-file fenris-0.3.0-1.fc40.x86_64.rpm \
+  "https://git.bongbetic.com/api/packages/xavierk/rpm/el9/upload"   # e.g. el9, rocky/el9, fc40
+```
+
+- Group = free-form nesting used to partition repos per distro/track. Verified: publish to root group and `el9` group (both 201), duplicate → 409.
+- Owner can be the user (`xavierk`) or an org; packages under a public owner are readable anonymously (verified: metadata fetches without auth succeeded).
+
+## 2. Consumer setup (exact commands)
+
+### apt clients
+
+```bash
+sudo mkdir -p /etc/apt/keyrings
+sudo curl -o /etc/apt/keyrings/gitea-xavierk.asc \
+  https://git.bongbetic.com/api/packages/xavierk/debian/repository.key
+echo "deb [signed-by=/etc/apt/keyrings/gitea-xavierk.asc] https://git.bongbetic.com/api/packages/xavierk/debian bookworm main" \
+  | sudo tee /etc/apt/sources.list.d/gitea.list   # one line per distribution
+sudo apt update
+apt install fenris            # or fenris=0.3.0
+# private owner variant: https://{user}:{token}@git.bongbetic.com/api/packages/... in the URL
+```
+
+### dnf clients
+
+```bash
+sudo dnf config-manager --add-repo https://git.bongbetic.com/api/packages/xavierk/rpm/el9.repo
+# private owner: add user:token into the baseurl inside /etc/yum.repos.d/gitea-xavierk-el9.repo afterwards
+sudo dnf install fenris       # or fenris-0.3.0
+```
+
+The served `.repo` (verified live) sets `gpgcheck=1` and points `gpgkey` at `…/rpm/repository.key`, so `dnf` auto-imports on first use.
+
+## 3. Metadata signing: native, not passthrough
+
+Gitea **signs generated metadata itself** with per-instance auto-generated PGP keys. Client-side signing config is limited to trusting the served keys.
+
+- Debian: `dists/{suite}/InRelease` is clearsigned; `Release.gpg` detached sig also served. Key (RSA) fetched from `…/debian/repository.key`, uid literally `(Automatically generated Debian Registry Key; created …)`.
+- RPM: `repodata/repomd.xml.asc` detached ASCII-armored signature, uid `(RPM Registry)`. Key from `…/rpm/repository.key`.
+- Both verified with `gpg --verify` → **Good signature** (keys are self-generated; the "not certified" warning is expected and handled by the signed-by/keyring flow above).
+- The apt `Release` also advertises `Acquire-By-Hash: yes` with MD5/SHA1/SHA256/SHA512 indexes of `Packages`/`.gz`/`.xz` (verified live). RPM repomd carries sha256 checksums for `primary/filelists/other.xml.gz`.
+
+There is **no bring-your-own-signing-key config** for these registries in 1.27 — trust anchor is the instance's auto keys. For Fenris this is acceptable; TOFU over TLS via the key URLs above.
+
+## 4. Multi-distro metadata
+
+- Debian: distributions/suites are implicit — whatever `{distribution}` path segments appear on upload become `dists/{distribution}/` trees with `Suite:`/`Codename:` set to the segment. No server-side list to maintain; adding a new distro = upload with new segment + one more `deb …` sources line. Components likewise (`main`, etc.). Architectures come from each `.deb`'s control stanza (index served as `dists/{dist}/{component}/binary-{arch}/Packages`).
+- RPM: same via `{group}` path segments (`el9`, `rocky/el9`, …); each group gets its own `repodata/`. No `basearch` filtering — clients pick the group; Gitea publishes whatever RPM arch was uploaded.
+
+## 5. Version retention
+
+- Default: **all versions retained indefinitely**; nothing auto-deletes. Old versions stay installable (`apt install fenris=0.2.9`, `dnf install fenris-0.2.9`).
+- Republishing an existing name+version (deb: same dist/component/arch; rpm: same file name in group) → 409; overwrite requires delete-then-upload.
+- Optional cleanup rules exist (per owner + package type): `KeepCount`, `KeepPattern`, `RemoveDays`, `RemovePattern`, `MatchFullName` (source: `models/packages/package_cleanup_rule.go`, executed by scheduled `CleanupTask` in `services/packages/cleanup/cleanup.go`). In 1.27.1 they are configurable **only in the web UI** (owner → Packages → Cleanup Rules); no v1 REST route (verified by route table grep of `routers/api/v1/api.go` — probes of `/api/v1/packages/{owner}/cleanuprules…` return 404/409-style errors).
+- Deletes: format-specific `DELETE …/debian/pool/{dist}/{component}/{name}/{version}/{arch}` and `DELETE …/rpm/{group}/package/{name}/{version}/{arch}` (both verified, 204). Deleting last file removes the version. Generic fallback: `DELETE /api/v1/packages/{owner}/{type}/{name}/{version}`.
+
+## 6. Release attachment: not supported
+
+Gitea 1.27.1 has **no package↔release linkage**. Release assets (`…/releases/{id}/assets`) are standalone file uploads; the package model has no release field and no route links them (verified against `v1.27.1` source: `routers/api/v1/repo/release_attachment.go`, `models/packages/`). Options for Fenris releases:
+
+1. Publish `.deb`/`.rpm` to the registry (real apt/dnf install UX) and reference the registry URLs in release notes.
+2. Additionally upload tarballs/SHA256SUMS as plain release attachments.
+3. Generic registry (`PUT /api/packages/{owner}/generic/{name}/{version}/{filename}`) if an untyped artifact store is needed.
+
+## 7. Caveats for the release plan
+
+- Owner choice matters: publish under an **org** (e.g. `fenris`) if multiple maintainers need write; `xavierk` user owner works today (token owner is admin).
+- Metadata access follows owner visibility — public owner → anonymous consumers, no token in URLs (current state, verified). Keep owner public for frictionless installs, or embed `user:token` in sources/baseurl.
+- apt distro naming should match OS release names (`bookworm`, `trixie`, `noble`) purely for client convention; server accepts anything.
+- RPM groups should mirror `$distver` (e.g. `el9`, `fc40`) so `.repo` selection is obvious per target.
+
+## 8. Test log (live, 2026-09-03)
+
+| Step | Result |
+|---|---|
+| `PUT debian/pool/bookworm/main/upload` | 201 |
+| `PUT debian/pool/noble/main/upload` (multi-dist) | 201 |
+| `PUT debian` duplicate | 409 (expected) |
+| `PUT rpm/upload` (no group) | 201 |
+| `PUT rpm/el9/upload` (group) | 201 |
+| `PUT rpm` duplicate | 409 (expected) |
+| `GET debian/repository.key` / `rpm/repository.key` | PGP public keys (200) |
+| `GET dists/bookworm/{Release,InRelease,Packages}` | correct; `gpg --verify` Good signature |
+| `GET rpm{,/el9}/repodata/repomd.xml{,.asc}` | 200; Good signature |
+| `GET rpm{,/el9}.repo` | generated repo files with `gpgcheck=1` |
+| Cleanup-rules REST probes | 404 (not in v1 API — UI only) |
+| `DELETE` all four test entries | 204 ×4; package list then empty |
+
+Sources: [docs.gitea.com 1.27 Debian registry](https://docs.gitea.com/1.27/usage/packages/debian), [docs.gitea.com 1.27 RPM registry](https://docs.gitea.com/1.27/usage/packages/rpm), Gitea source tag `v1.27.1` (`routers/api/v1/api.go`, `models/packages/package_cleanup_rule.go`, `services/packages/cleanup/cleanup.go`), live instance `git.bongbetic.com`.

docs/research/obs-route.md

@@ -0,0 +1,73 @@
+# Research: OBS as an alternative build + distribution route
+
+Resolves [Research: OBS as alternative build + distribution route](https://git.bongbetic.com/xavierk/Fenris/issues/36) on the [Wayfinder map](https://git.bongbetic.com/xavierk/Fenris/issues/33).
+
+- Date: 2026-09-03
+- Verdict: **Reject OBS now; ship via the self-hosted Gitea 1.27.1 registry** (deb + rpm), and revisit OBS only if publishing reach becomes a goal.
+
+## Question
+
+Evaluate openSUSE Open Build Service (OBS) as the build + distribution route — deb build quality, vendoring `textual>=0.40` via source services (offline sandbox), signing, publishing reach, account/maintenance cost, build latency — against the Gitea registry on our matrix: Debian 12, Ubuntu 22.04/24.04, Fedora 40+, x86_64.
+
+## Findings
+
+### 1. deb build support quality — real, with quirks
+
+- OBS builds deb via the classic recipe trio: `debian.control`, `debian.rules`, `PACKAGE.dsc` (OBS User Guide §2.3 "Debian: Dsc"). The build phase runs `dpkg-buildpackage` on Debian-based distributions (§25.1.3 "Package Build"); Debian build environments can alternatively use the `debootstrap` build engine (§"Configuration File Syntax", `BuildEngine`).
+- Quirk: release numbers are **not** auto-incremented across rebuilds unless the dsc carries `DEBTRANSFORM-RELEASE` (§2.3) — a packaging decision we'd own either way.
+- Upstream build deps are available: `dh-virtualenv` and `dh-python` exist in Debian 12 (packages.debian.org, checked 2026-09-03), so the ADR-0004 venv/lockfile design maps onto an OBS dsc without patching the build root.
+- All five matrix targets exist as public OBS build roots: `Debian:12`, `Ubuntu:22.04`, `Ubuntu:24.04`, `Fedora:40`, `Fedora:41` — each project `_meta` answered HTTP 200 on build.opensuse.org (checked 2026-09-03).
+- Live proof of deb publishing quality: `isv:ownCloud:desktop/Debian_10` on download.opensuse.org serves a proper Debian archive (`Release`, `Release.gpg`, `InRelease` all HTTP 200, checked 2026-09-03).
+
+### 2. Vendoring textual≥0.40 — the offline sandbox forces the same work we already planned
+
+- The build environment has **no network**: "services requiring external network access are likely to fail in [buildtime] mode, because such access is not available if the build workers are running in secure mode (as is always the case at https://build.opensuse.org)" (User Guide §7.2, "Modes of Source Services"); Dockerfile builds likewise run "in a safe build environment without network access" (§29.3).
+- Vendoring must therefore happen **before** the build, via source services that run server-side on commit (`default`/`trylocal` modes, §7.2) or via files committed to the package. The standard services are per-file fetchers — `download_url` (§22.1.3), `download_files`, `obs_scm`/`tar`/`set_version` (§8 SCM integration) — there is no "pip resolve" service, so a pinned dependency tree like Fenris's means either N `download_url` entries mirroring the committed lockfile, or simply committing the vendored wheel/sdist tree.
+- Conclusion: OBS does not remove the vendoring step; it reproduces ADR-0004's committed-lockfile design with extra XML. Since distro `python3-textual` is 0.1.13 on Debian 12, Ubuntu 22.04 and 24.04 (packages.debian.org / packages.ubuntu.com, checked 2026-09-03) — far below the `>=0.40` floor — vendoring is unavoidable on any route.
+
+### 3. Signing — OBS key, not ours; Gitea deb repo is our key
+
+- OBS signs published repositories with the **instance's** key: one signer per partition "calls an external tool to execute the signing" (User Guide §23 "OBS Architecture", Signer); consumers accept the OBS repo key ("When prompted, accept the GPG key of the download repository", §1.10). A build.opensuse.org user cannot upload a personal signing key. Trust therefore flows to openSUSE infra, and the signature says nothing about Fenris's maintainers.
+- Gitea 1.27.1's Debian registry serves apt metadata signed with the Gitea instance's PGP key (`repository.key` endpoint, `signed-by` in sources.list — docs.gitea.com, "Debian Package Registry"), i.e. **our** host and **our** key. The RPM registry serves a `.repo` endpoint but documents no GPG signing of repodata; rpm-file signing stays our choice at build time.
+
+### 4. Publishing reach — OBS wins reach; reach is not our bottleneck
+
+- OBS publishes home-project results to `https://download.opensuse.org/repositories/home:USER/<dist>` (§1.10) and offers generated download pages on software.opensuse.org (§17.4). That is genuine CDN-class reach.
+- Caveats from the same docs: branched projects are **not** published by default (§1.10), and the repo is a live view of the project state — no release artefact pinning; deleting the project or flag disables distribution.
+- The Gitea route's reach is exactly `git.bongbetic.com` plus whatever the README says — adequate for a named four-distro matrix whose users follow our instructions, and it keeps the release artefact under versioned control on the same host as the source.
+
+### 5. Account and maintenance cost — strictly additive
+
+- Using build.opensuse.org requires an openSUSE account (single sign-on; the web UI's "Sign up!") and work happens in `home:USERNAME` plus permitted subprojects (§"Setting Up Your Home Project for the First Time"; §23 "OBS Concepts" on home projects).
+- Day-to-day: `osc` + `_service` XML + dsc/spec recipes maintained in OBS's own package VCS, kept in sync with Fenris's git. The SCM bridge (`scmsync`) does support self-hosted Gitea ("We also support Self-Hosted instances from GitHub, GitLab and Gitea", §8.1.3; setup in §28.1.2 — build descriptions must live in the repo's top level), but it also disables OBS-side workflows (no `_link` merging, limited workflows, §28.1.1).
+- No published quota/SLA for the public instance; capacity and availability are a shared commons. The Gitea route needs zero new accounts, zero new artefact formats beyond the two package recipes we must write anyway, and reuses the existing release host.
+
+### 6. Build latency — shared queue vs. deterministic local
+
+- OBS routes every commit through scheduler → dispatcher → shared workers; the dispatcher "tries to assign jobs fairly between the project repositories" using a per-repository load model (§23, Scheduler/Dispatcher). For our five tiny x86_64 jobs this is typically minutes, but there is no documented SLA and the queue is global — worst case is unbounded (estimate; the docs guarantee only fairness, not latency).
+- The Gitea route builds wherever `make` runs and publishes with one authenticated `PUT` per artefact (docs.gitea.com: Debian `PUT .../pool/{distribution}/{component}/upload`; RPM `PUT .../rpm/{group}/upload`). Latency = build time, fully under our control.
+
+## Comparison on the 4-distro matrix
+
+| Axis | OBS (build.opensuse.org) | Gitea 1.27.1 registry |
+|---|---|---|
+| Debian 12 / Ubuntu 22.04/24.04 deb | dsc + dpkg-buildpackage; DEBTRANSFORM-RELEASE quirk | we build the same deb locally, upload via PUT |
+| Fedora 40+ rpm | spec + rpmbuild in Fedora roots | same spec built locally, `.repo` grouping (`fedora/40`) |
+| Vendoring textual≥0.40 | offline sandbox forces committed vendored tree (no pip service) | same committed vendored tree (ADR-0004 lockfile) |
+| Signing | OBS instance key (not ours) | deb repo signed with our key; rpm repodata unsigned |
+| Reach | download.opensuse.org CDN + software.o.o pages | our domain only |
+| Accounts/infra | new openSUSE account, osc workflow, commons SLA-free | zero new infra |
+| Latency | global shared queue, minutes typical, no SLA | deterministic (local build) |
+
+## Recommendation
+
+**Reject OBS as the build + distribution route for Fenris.** The offline sandbox forces the exact vendoring work the Gitea route already requires, so OBS adds cost (account, osc/source-service maintenance, external commons in the release path, queue latency) without removing any; its one real advantage — CDN and software.o.o reach — does not matter for a hobby project whose four target distros are served by one signed apt repo and one rpm repo on the existing Gitea host, under our own key.
+
+Revisit trigger: if Fenris later wants one-click installs via software.opensuse.org, architectures beyond x86_64, or many more distro targets — the deb publishing quality (verified live) and self-hosted-Gitea SCM bridge make OBS a viable amplifier then.
+
+## Sources
+
+- OBS User Guide (openbuildservice.org/help/manuals/obs-user-guide/, PDF): §2.3 Debian: Dsc; §7 Using Source Services (offline buildtime services, modes); §8.1.3 Supported SCMs; §17.4 download pages; §22.1.3 download_url; §23 OBS Architecture (Scheduler/Dispatcher/Signer); §25.1.3 Package Build; §28.1 SCM bridge; §29.3 Dockerfile builds (no network); §1.10 Installing Packages from OBS; "Configuration File Syntax" (BuildEngine, Repotype: debian).
+- Live checks (2026-09-03): `Debian:12`/`Ubuntu:22.04`/`Ubuntu:24.04`/`Fedora:40`/`Fedora:41` project `_meta` on build.opensuse.org (all 200); `isv:ownCloud:desktop/Debian_10` `Release`/`Release.gpg`/`InRelease` on download.opensuse.org (all 200).
+- packages.debian.org / packages.ubuntu.com (2026-09-03): `python3-textual` 0.1.13 on bookworm, jammy, noble; `dh-virtualenv`, `dh-python` present in bookworm.
+- docs.gitea.com, "Debian Package Registry" and "RPM Package Registry" (1.27 line): apt sources with `signed-by` + `repository.key`, `PUT` upload endpoints, `.repo` groups.

docs/spec/acceptance-criteria.md

@@ -0,0 +1,146 @@
+# Acceptance criteria: the Fenris redesign
+
+Status: Accepted — resolves [Define cross-cutting acceptance criteria](https://git.bongbetic.com/xavierk/Fenris/issues/13) on the [Wayfinder map](https://git.bongbetic.com/xavierk/Fenris/issues/1). These criteria are the accepted definition of done for the finished redesign; the implementation-ready specification assembles them with ADRs 0001–0006 at handoff.
+
+## Framework
+
+- **Canonical term**: *acceptance criterion* — one testable behavioral statement. "Behavioral gate" is avoided as a synonym. Wording follows the repository glossary (`CONTEXT.md`).
+- **Evidence classes** — every criterion carries exactly one:
+    - **A** — automated test (unit/integration, fixture-driven).
+    - **P** — scripted system probe on a host with systemd, polkit, and the configured NVMe device.
+    - **M** — manual checklist, reserved for interactions a fixture cannot capture (live polkit agent prompts, TUI keyboard feel).
+    - Whatever can be automated must be; **M** only where automation cannot reach.
+- **Traceability-only**: every number and behavior cites the ADR or ticket that fixed it. Nothing undecided enters here; new demands become new tickets, never criteria.
+- **Organization**: criteria are grouped by subsystem, with cross-cutting invariants spanning them. Coverage spans all decided areas — observation store and migration, collector lifecycle and privileges, projection and confidence, controller identity, the Panes TUI, failure paths, and installation lifecycle.
+- **Placeholders**: none remain. SLOT-B was filled by [Choose the collector's NVMe acquisition path](https://git.bongbetic.com/xavierk/Fenris/issues/16) as AC-1–AC-5; SLOT-A was filled by [Decide how degraded identity affects projection confidence](https://git.bongbetic.com/xavierk/Fenris/issues/15) as PR-15, PR-16, and ID-4.
+- **Test-plan boundary**: Given/When/Then test specs are derived by the implementer at implementation time. This effort produces criteria only.
+
+## Cross-cutting invariants
+
+- **CI-1** (A; ADR 0002 §§6–8, ADR 0003 §10) *Exhaustive state matrix*: from a synthetic observation store, the TUI and `fenris status` render every realizable combination of confidence state (Unavailable, Limited, Supported) × freshness grade (fresh, missed, stale, empty store) × endurance-baseline tier (verified override, unverified override, implied, none) exactly as the ADR 0002 rule table and ADR 0003 freshness constants dictate — headline number present only when the rules allow it, contributing facts always, never a percentage.
+- **CI-2** (P/A; ADR 0003 §§4–9) *TUI/CLI parity*: every TUI action has a CLI twin — pause (`fenris monitor pause`), resume (`fenris monitor resume`), collect-now (`fenris sample`), baseline set/clear, and the status fact set — with identical outcomes and wording.
+- **CI-3** *Prohibition set* (A = test, P = probe; each cites its clause):
+    - No code path outside `fenris-collect` interrogates the device (ADR 0003 §7).
+    - No `/run/fenris` coordination surface or export layer exists anywhere; state lives in the observation store and coordination in systemd (ADR 0003 §1, ADR 0001 §2).
+    - Polkit authorizes exactly one binary, `fenris-monitor`, under `com.bongbetic.fenris.monitor` `auth_admin` (ADR 0003 §5, ADR 0004 §3).
+    - No absent hour is ever interpolated, estimated, or fabricated (ADR 0005 §2).
+    - No alerting, notification, or escalation machinery exists anywhere (ADR 0005 §§5–6).
+    - `/etc/fenris/fenris.conf` holds exactly one key — the device selector (ADR 0003 §3).
+    - No synthetic or capacity-derived baseline is ever created, including for legacy history (ADR 0002, Consequences).
+    - Readers never partially interpret a newer-schema store (ADR 0001 §8, ADR 0005 §4).
+    - Projections are never stored; always recomputed on read (ADR 0001 §3, ADR 0002 §13).
+- **CI-4** (A; ADR 0002 §§11–12) *User-facing language*: TUI and status render the endurance research's required wording and six disclosures as adopted; zero-rate and unavailable cases use their exact phrasing; the scenario range is the only spread shown anywhere.
+
+## Observation store and legacy migration (ADR 0001)
+
+- **ST-1** (P) One SQLite database in WAL mode at `/var/lib/fenris/observations.db`, root-owned and group-readable through the `fenris` read group; the TUI opens it read-only.
+- **ST-2** (A) An unprivileged reader querying during a collector write sees a consistent snapshot.
+- **ST-3** (A) The schema carries `samples`, `hour_observations`, `day_aggregates`, `monitoring_periods`, `controller_segments`, and `endurance_baseline` with the ADR 0001 column sets as amended by [Define endurance-baseline provenance and validation](https://git.bongbetic.com/xavierk/Fenris/issues/12) and [Decide controller-segment metadata columns](https://git.bongbetic.com/xavierk/Fenris/issues/14).
+- **ST-4** (A) Hours and days are UTC-bounded; day derivation from hours is monotonic; no 23- or 25-hour days exist.
+- **ST-5** (A) Raw samples are pruned opportunistically to 14 days; hour observations and day aggregates are retained indefinitely.
+- **ST-6** (P) Legacy import is one transaction: a scripted kill mid-import leaves the store fully pre- or fully post-migration.
+- **ST-7** (A) Import is idempotent: a second run no-ops on the legacy-import marker.
+- **ST-8** (A) Legacy files are renamed `*.migrated` only after commit and never deleted.
+- **ST-9** (A) Malformed legacy lines are quarantined with a logged count, never silently dropped.
+- **ST-10** (A) `hourly.jsonl` is never trusted: mismatches against derived data are diffed and logged.
+- **ST-11** (A) Migration opens one implicit monitoring period at the first legacy sample, closed `end_cause = migrated` at the migration moment; pre-migration hours carry an unknown activity split except directly evidenced facts.
+- **ST-12** (A) Schema versioning: `PRAGMA user_version` with ordered, per-step transactional migrations; the collector refuses an unknown newer version.
+
+## Collector lifecycle and privilege boundaries (ADR 0003)
+
+- **LC-1** (P) Exactly two system units exist — `fenris-collect.timer` (`timers.target`) and `fenris-collect.service` (`Type=oneshot`, root, `ExecStart=/usr/libexec/fenris/fenris-collect`); the TUI and CLI are ordinary unprivileged processes and never units.
+- **LC-2** (P) Timer defaults ship as `OnBootSec=2min`, `OnUnitInactiveSec=5min`, `AccuracySec=30s`, `Persistent=no`, `TimeoutStartSec=90s`; cadence changes are documented drop-ins and no interval key exists in configuration.
+- **LC-3** (P) A hung device interrogation fails visibly within `TimeoutStartSec=90s` as a bounded failed run retried next interval.
+- **LC-4** (A/P) `/etc/fenris/fenris.conf` holds exactly the device selector (stable `/dev/disk/by-id/…` path; raw nodes warned), re-read every run; an invalid selector is a bounded failed run surfaced as `configuration error: <reason>` in `status` and the TUI.
+- **LC-5** (P) Two privileged binaries ship at `/usr/libexec/fenris/fenris-collect` and `/usr/libexec/fenris/fenris-monitor`; the unprivileged `fenris` wrapper opens the TUI with no arguments.
+- **LC-6** (P+M) Pause = `fenris-monitor disable --now` asks for confirmation; Resume = `enable --now` does not; both perform the systemctl operation and period bookkeeping in one step under polkit `com.bongbetic.fenris.monitor` (`auth_admin`), failing cleanly with the printed root equivalent where no polkit agent exists. (M covers the live agent prompt.)
+- **LC-7** (A) The period-row idempotent matrix of ADR 0003 §6 holds exactly: first-ever enable opens; resume with an open period changes nothing; resume without one opens anew; pause with an open period closes `user_disabled`; pause otherwise no-ops; a raw systemctl stop/disable never records `user_disabled`.
+- **LC-8** (P) `fenris sample` and the TUI's collect-now route through `fenris-monitor` → `systemctl start fenris-collect.service`, block until exit, and report the outcome (freshness line or journal hint) synchronously; the TUI never samples in-process.
+- **LC-9** (A/P) CLI compatibility: `status` is a read-only composition (projection facts, enabled/active, last collect outcome, `journalctl` hint on failure or staleness) that never auto-samples and never prompts; `sample` is retained via the helper; `--device` is rejected with a pointer to the configuration file; `start`, `stop`, and `run` are rejected with one-line migration pointers; `fenris.sh` is not shipped and is removed from the repository; the README maps its five menu options to successors.
+- **LC-10** (A) Freshness constants are defined once and shared by TUI and CLI: fresh = newest sample within 2× cadence + `AccuracySec` + 60 s; missed between that and 48 h; stale ≥ 48 h; an empty store reads "no observations yet" with an enable hint; freshness derives from the newest sample timestamp, never a stored health flag.
+
+## Projection contract and confidence (ADR 0002)
+
+- **PR-1** (A) Exactly one projection, from the precedence-chosen baseline (verified override → unverified override → implied → unavailable); Percentage Used renders as a vendor-wear context line, with a note when it disagrees with the observed write rate by more than a factor of 2; the PU-slope regression and `capacity × 600` synthesis are gone.
+- **PR-2** (A) The headline rate is the sustained-regime rate (regime DUW bytes ÷ in-period wall-clock seconds), default regime = full history capped at 90 days; the 7/28/90-day scenario range is computed independently and shows only covered horizons, with no placeholders.
+- **PR-3** (A) Habit change: trailing 7-day mean ≥ 2× or ≤ 0.5× the preceding 28-day mean for 3 consecutive days starts a new regime at the first divergence day, adopted automatically and labeled "usage habit changed N days ago"; a regime younger than 7 days caps confidence at Limited evidence.
+- **PR-4** (A) Hour classification uses the named constants: powered-off below 90% of power-on-hours span; active at ≥ 256 MiB DUW; idle below it while powered on and sampled; unknown otherwise; disabled time is wall-clock outside monitoring periods, never an hour state.
+- **PR-5** (A) The denominator is wall-clock seconds inside monitoring periods including powered-off and unknown time; disabled periods are excluded from numerator and denominator; unexplained gaps keep the aggregate counter delta, remain as unknown seconds, and reduce coverage.
+- **PR-6** (A) Warming up until 14 distinct UTC day aggregates of which at most 2 fall below 50% coverage; the projection still renders with its facts while warming; every Unavailable condition renders no lifespan number.
+- **PR-7** (A) A newest day aggregate older than 48 h drops confidence one level and is shown as a contributing fact.
+- **PR-8** (A) The confidence rule table of ADR 0002 §8 holds verbatim, rendering state plus contributing facts and never a percentage.
+- **PR-9** (A) Segment breaks: a DUW decrease with unchanged identity keeps prior day aggregates as habit evidence with the projection Unavailable until re-warm; a controller-identity change quarantines prior history from projection entirely.
+- **PR-10** (A) The implied baseline is eligible only after ≥ 2 Percentage-Used increments within the current controller segment; until then, Unavailable with "vendor wear estimate too coarse to imply endurance".
+- **PR-11** (A) Zero rate renders "no finite projection from this history" — never infinity or zero; no statistical confidence interval appears anywhere.
+- **PR-12** (A) The projection contract hands the TUI exactly: confidence state, contributing facts, headline remaining time when one exists, scenario range, Percentage-Used context line, disclosure text — recomputed on read, never stored.
+- **PR-13** (A) Baseline provenance and validation per [Define endurance-baseline provenance and validation](https://git.bongbetic.com/xavierk/Fenris/issues/12): mandatory provenance (URL, revision, entry date, model, nominal capacity); one active row replaced on edit; verification derived at read (machine match or recorded attestation), never a stored boolean; incomplete provenance stores only behind explicit acknowledgment as the unverified tier; entry-time unprivileged sysfs validation (normalized model containment; capacity within ±1%; interactive confirm recorded as `validated_by = user`); read-time applicability is a model match against the current controller segment, with a mismatch retained — never auto-deleted — leaving the projection Unavailable.
+- **PR-14** (P) `baseline set` / `baseline clear` persist through the polkit-guarded `fenris-monitor` verb after CLI-side validation.
+- **PR-15** (A) An identity-degraded controller segment (blank identity key — every rung of the key ladder empty) caps projection confidence at Limited evidence, with the contributing fact "controller identity unavailable — replacement detection relies on write-counter continuity only" rendered in every state; the cap combines idempotently with the 48-hour staleness drop, and ephemeral markers (model "Linux", non-pcie transport) never render as confidence facts ([Decide how degraded identity affects projection confidence](https://git.bongbetic.com/xavierk/Fenris/issues/15); ADR 0002 §§8–9 as amended).
+- **PR-16** (A) Identity-change semantics extend to blank keys verbatim: any visible change of the recorded identity key — including to or from a blank key — quarantines prior history from projection as a controller-identity change, while equal blank keys continue the segment segmented by DUW monotonicity alone (ADR 0002 §9 as amended).
+- **PR-17** (A) Projection arithmetic is exactly `E_rated = entered_TBW × 10¹²` bytes, `E_implied = 100 · W_t / p` computed only for `1 ≤ p ≤ 254` (Percentage Used of 0 or saturated 255 implies no baseline — that precedence tier is unavailable), and `projected = max(E_baseline − W_t, 0) / rate` for `rate > 0` (ADR 0002 §2).
+
+## Controller identity ([Verify the controller identity that segments observation history](https://git.bongbetic.com/xavierk/Fenris/issues/11), [Decide controller-segment metadata columns](https://git.bongbetic.com/xavierk/Fenris/issues/14); ADR 0001 §3 as amended)
+
+- **ID-1** (A) The controller-segment identity key is the normalized kernel-exposed subsystem NQN, with the kernel composite then model|serial as fallbacks; FR is metadata only; identity change and DUW decrease act as independent axes.
+- **ID-2** (A) Segments freeze a fully nullable metadata snapshot at open — normalized `subnqn`/`sn`/`mn`/`fr` plus `vid`/`ssvid`/`transport` and `identity_degraded` — immutable thereafter, with `cntlid` excluded.
+- **ID-3** (A) Legacy history imports under a labeled model-scoped legacy identity (mn-only segments).
+- **ID-4** (A) `identity_degraded` is set at segment open exactly when the identity key is blank; keys from the kernel-composite or `model|serial` rungs are not degraded ([Decide how degraded identity affects projection confidence](https://git.bongbetic.com/xavierk/Fenris/issues/15)).
+
+## Panes TUI ([Prototype the TUI information architecture](https://git.bongbetic.com/xavierk/Fenris/issues/3), [Evaluate Python TUI frameworks](https://git.bongbetic.com/xavierk/Fenris/issues/6); ADR 0003 §§8, 10; ADR 0004 §10)
+
+- **TUI-1** (A) Variant A "Panes": one dense keyboard-first screen; confidence rendered as evidence (state + contributing facts); boot enablement, runtime activity, last collect outcome, and freshness displayed as four separate facts.
+- **TUI-2** (M) Pause/resume asymmetry and polkit tty passthrough work in a live terminal: pause confirms, resume does not, and the platform agent prompts without breaking the TUI.
+- **TUI-3** (P) Textual runs on Python 3.9+, gated at install time, never a runtime crash.
+- **TUI-4** (A) The Panes screen layout is normative: a full-width headline band (lifespan headline or its no-projection wording, confidence state with contributing facts, scenario range); a usage-history pane on the left (write-history sparkline with ▲ habit-change and ? unexplained-gap markers plus legend, habit-split bar with active/idle/powered-off/unknown shares); a drive-health and settings pane on the right (health facts, vendor-wear context line, read-only settings with the endurance baseline and its provenance label); a full-width service strip at the bottom (the four separate service facts, the monitoring-period line, the action legend). Production bindings are the footer `p pause · r resume · c collect · d disclosures` — pause asks, resume does not — plus a bordered quit rail `q QUIT TUI` visually separate from monitoring state; the rail owns quit and the footer carries no quit entry (bindings amended by [Lock the dashboard wording strings](https://git.bongbetic.com/xavierk/Fenris/issues/57); original [Prototype the TUI information architecture](https://git.bongbetic.com/xavierk/Fenris/issues/3)); the prototype branch is visual reference only.
+
+## Failure and recovery (ADR 0005)
+
+- **FL-1** (A) The collector validates every row against the store invariants (hour seconds sum to 3600; non-negative DUW delta within a controller segment; coverage consistent with sample count); a violating run writes nothing, logs the refused row, and fails visibly.
+- **FL-2** (A) Readers defensively exclude and count malformed rows as a contributing fact.
+- **FL-3** (A) No backfill ever: gaps remain unknown seconds; degradation flows only through coverage, freshness facts, and confidence categories.
+- **FL-4** (P/A) A store fault surfaces "observation store unreadable" with a journal hint and suppresses everything else store-dependent; the collector treats it as a bounded failed run and never recreates or overwrites the file; recovery is the documented human-sanctioned move-aside (with `history.jsonl` re-import if the legacy import never completed); no built-in destructive command exists.
+- **FL-5** (A) A newer-schema store renders "observation store written by a newer Fenris — upgrade Fenris" in TUI and status, with no partial interpretation.
+- **FL-6** (A/P) Repeated collector failures retry at flat cadence with no backoff or notification; persistence reads as stale exactly like any other gap.
+- **FL-7** (A) `critical_warning`, media errors, and unsafe shutdowns render as ordinary facts in TUI and status and never affect the projection.
+- **FL-8** (A) A collection run finding no open monitoring period opens one at the run moment, never backdated.
+
+## Installation, upgrade, and removal (ADR 0004)
+
+- **IN-1** (P) `sudo make install` builds a wheel from the checkout and installs pinned dependencies into the dedicated venv at `/opt/fenris`, with a `/usr/local/bin/fenris` wrapper; after install nothing references the checkout.
+- **IN-2** (P) The installer records every placed file in an explicit manifest consumed by upgrade and uninstall.
+- **IN-3** (P) The installer never enables or starts units: a fresh install is dormant (units disabled, nothing running, no monitoring period); the only opt-in is the sanctioned toggle — `fenris monitor resume [--now]` or the first-run TUI prompt — enabling the timer and opening the first period in one step.
+- **IN-4** (P) Install-time legacy import detects `./data/history.jsonl` (or an explicit path), runs the idempotent single-transaction import, and reports imported counts; `fenris import <path>` remains available.
+- **IN-5** (P) `sudo make upgrade` installs into the same venv, syncs units and polkit against the manifest (`daemon-reload`; timer restarted only if unit contents changed and it is active), never kills an in-flight collection run, then applies forward-only schema migrations; `/var/lib/fenris` is never rebuilt.
+- **IN-6** (P) Before migrations, `observations.db` is snapshotted to a one-generation `.bak`; rollback is reinstall-previous plus restore; automatic schema downgrade does not exist.
+- **IN-7** (P) `make uninstall` performs the sanctioned disable first (open period closes `user_disabled`), then removes venv, helpers, units, polkit policy, and wrapper while keeping `/etc/fenris` and the observation store; `make purge` additionally removes configuration and store.
+- **IN-8** (P) Dependencies are exact pins in a committed lockfile installed by both install and upgrade; refreshing pins is an explicit `make update-deps` step, never an install side effect.
+- **IN-9** (P) The installer verifies `python3 ≥ 3.9` and fails cleanly otherwise; `/var/lib/fenris` is created with root-written group-read permissions; the database file is created lazily by the first write.
+- **IN-10** (P) Installed artifacts sit only at their fixed locations — units in `/etc/systemd/system`, helpers in `/usr/libexec/fenris`, polkit policy under `/usr/share/polkit-1/actions/`, configuration at `/etc/fenris`, observation store under `/var/lib/fenris` — and every placed file is recorded in the manifest (ADR 0004 §2; ADR 0003 §4).
+
+## Migration from make-install systems (ADR 0007 §10, spec §9)
+
+- **MG-1** (M) The migration runbook is published in the install docs (`docs/install/migrate-from-makeinstall.md`): mandatory remove-then-install steps, why over-install is forbidden (stale admin-directory units silently shadow vendor units; the local wrapper shadows the package wrapper), no-move continuity, and the reset-to-dormant expectation (the user opts back in with the sanctioned resume).
+- **MG-2** (A) The install guard is verified across the matrix: either make-install marker (the legacy placement manifest, or a unit file under the admin unit directory) causes an abort with a runbook pointer — never auto-clean. Tested by `test_migration_guard` on all four targets (Debian 12, Ubuntu 22.04, Ubuntu 24.04, Fedora 40).
+- **MG-3** (A) No-move continuity is verified in a container seeded with a make-install-shaped system: existing group makes sysusers a no-op, existing store directory makes tmpfiles a no-op, the hand-written configuration survives as a non-database file (package default lands beside it), and the store schema is caught up by the upgrade-path migration. Tested by `test_no_move_continuity_deb` and `test_no_move_continuity_rpm`.
+- **MG-4** (M) The migration costs at most one short sample gap, honestly recorded in the endurance timeline: `make uninstall`'s sanctioned disable closes the open period `user_disabled`; after migration the user opts back in with `fenris monitor resume`.
+
+## Collector acquisition path (ADR 0006)
+
+- **AC-1** (P) Each collection run acquires counters and thermal evidence solely from `smartctl -a -j <device>` and controller identity (`subnqn`, `sn`, `mn`, `fr`, `transport`) solely from sysfs; no other acquisition path exists anywhere in the codebase.
+- **AC-2** (A) Identity normalization is applied exactly once, at write time — trailing spaces and newlines stripped, no case folding, empty-after-strip stored blank — so padded and unpadded renderings of the same field yield byte-identical stored values.
+- **AC-3** (A) Any acquisition failure — missing binary, nonzero exit, malformed JSON, unreadable sysfs attribute — fails the whole collection run; no partial sample (identity without counters, or counters without identity) is ever written; the miss surfaces through ADR 0005 freshness, never as degraded identity.
+- **AC-4** (P) `vid`/`ssvid` are read from the PCI sysfs node when present and stored null otherwise; they are segment metadata only, never key components.
+- **AC-5** (P) `make install` verifies `smartctl` and fails cleanly otherwise; the acquisition path adds no Python dependency and no OS package beyond smartmontools (ADR 0004 §9).
+
+## Dashboard clarity and release notes ([Chart Fenris dashboard clarity](https://git.bongbetic.com/xavierk/Fenris/issues/55))
+
+Decided in [Write the dashboard clarity acceptance criteria](https://git.bongbetic.com/xavierk/Fenris/issues/59), from [Prototype the dashboard clarity additions](https://git.bongbetic.com/xavierk/Fenris/issues/56), [Lock the dashboard wording strings](https://git.bongbetic.com/xavierk/Fenris/issues/57), and [Specify the changelog and release-notes mechanism](https://git.bongbetic.com/xavierk/Fenris/issues/58).
+
+- **DC-1** (A) TUI branding: the header bar renders `Fenris — NVMe endurance monitor`; a dimmed `by Bongbetic` sits inline with service facts in the bottom service strip; neither string appears in `fenris status` (TUI-only identity surfaces).
+- **DC-2** (A) Continuity parity, keyed to the boot fact as-is: active + boot-enabled renders `monitoring: active in background · persists across reboots`; boot-disabled renders `monitoring: does not start on next boot` — identical lowercase source strings in the TUI service strip and `fenris status`, including while paused (paused implies boot-disabled; the row still reports the fact). Test impact: feeds the CI-2 sweep (lowercase source-string comparison).
+- **DC-3** (A) Paused presentation (Deliberate disable): the TUI shows a strong state block titled `monitoring: paused — deliberate disable` with subline `paused time is excluded from your usage habit · resume: fenris monitor resume`; `fenris status` prints the same two lines with identical wording. Test impact: feeds the CI-2 sweep (lowercase source-string comparison).
+- **DC-4** (A) Quit affordance distinct from monitoring state: a bordered labelled rail `q QUIT TUI` visually separate from the paused state block; the footer reads `p pause · r resume · c collect · d disclosures` with no quit entry (the rail owns quit); quitting the TUI never alters monitoring state. Amends TUI-4's binding parenthetical.
+- **DC-5** (A) Launch auth banner: `privileged actions will prompt for authentication (polkit)` renders full-width under the header at TUI launch, clears on the first refresh tick, and never reappears in the session; no user-facing string uses "sudo" (polkit-accurate elevation wording only).
+- **DC-6** (A) CHANGELOG.md shape (Keep a Changelog 1.1): `## [Unreleased]` always present at top, even empty; version headings `## [X.Y.Z] - YYYY-MM-DD` with strict ISO date; categories Added/Changed/Fixed only, security folding into Fixed; entries are single `- ` bullets, imperative mood, user-facing, no commit hashes or issue numbers.
+- **DC-7** (A) Extraction fails closed: `scripts/extract_changelog.py` slices the requested version's section verbatim and never reads `[Unreleased]`; a missing or empty section or a malformed date produces `::error::` and a nonzero exit; the release workflow fails when the pushed tag ≠ `v{version from pyproject.toml}` (guard skipped on `workflow_dispatch`).
+- **DC-8** (A/P) Release body: the body is the extracted section verbatim plus the standing footer from `packaging/release-footer.md`; a re-run against an existing release PATCHes the body (re-sync is a feature) while uploaded assets skip idempotently. A covers assembly/PATCH-logic unit tests; P is one scripted `workflow_dispatch` verification of body assembly.

docs/spec/dashboard-clarity.md

@@ -0,0 +1,122 @@
+# Fenris dashboard clarity specification
+
+**Status: decision-complete.** Assembled by [Assemble the dashboard clarity specification and close the map](https://git.bongbetic.com/xavierk/Fenris/issues/60) from the closed tickets of the Wayfinder map [Chart Fenris dashboard clarity](https://git.bongbetic.com/xavierk/Fenris/issues/55). This document is normative for the follow-up **execution effort**; nothing here is implemented by the map.
+
+**Canonical roles.** The [redesign specification](fenris-redesign.md) (frozen) and [ADRs 0001–0007](../adr/) remain authoritative and untouched — this is a companion spec covering five dashboard clarity additions plus the changelog-driven release-notes mechanism. The [criteria register](acceptance-criteria.md) carries the testable statements: **DC-1–DC-8**, appended by this assembly, with **TUI-4's binding list amended** (§4). Terminology follows the glossary in [`CONTEXT.md`](../../CONTEXT.md), including *Deliberate disable* and *Release*.
+
+**Binding language.** *Must*, *exactly*, and *never* are normative.
+
+## How to read this document
+
+Five screen additions (§1–§5), one release-notes mechanism (§6), the verbatim string register (§7), and the README section to add at execution (§8). Each section cites its criteria. Source strings are lowercase; the TUI may render uppercase via styling only. Typography, governing every string: em-dash `—` separates a title from its qualifier; middle dot `·` joins facts within a line; UTF-8 is assumed. CI parity sweeps compare lowercase source strings — rendering case is styling, not wording.
+
+## 1. Header bar and Bongbetic credit — DC-1
+
+Visual base is treatment A, quiet integration: the existing Panes information architecture is preserved.
+
+- The header bar reads `Fenris — NVMe endurance monitor`.
+- The credit `by Bongbetic` renders dimmed, inline with service facts in the bottom service strip — never in the action row.
+- Both are TUI-only identity surfaces: `fenris status` never renders them.
+
+## 2. Continuity line — DC-2
+
+A labelled `CONTINUITY` row in the service strip (treatment B), mirrored by `fenris status` — the TUI/CLI parity anchor. The row is keyed to the boot fact as-is, independently of run state (Deliberate disable runs `systemctl disable --now`, so paused implies boot-disabled; the row still reports the fact):
+
+- Active + boot enabled: `monitoring: active in background · persists across reboots`
+- Boot disabled: `monitoring: does not start on next boot`
+
+Identical lowercase source strings in the TUI service strip and `fenris status`, including while paused.
+
+## 3. Paused state block — DC-3
+
+Treatment C, strong state blocks: when monitoring is paused, a full-width, high-contrast banner clearly identifying Deliberate disable:
+
+- Title: `monitoring: paused — deliberate disable`
+- Subline: `paused time is excluded from your usage habit · resume: fenris monitor resume`
+
+`fenris status` prints the same two lines with identical wording (state line + consequence line). The resume hint uses the CLI form only; the footer owns key hints — no duplication.
+
+## 4. Quit rail — DC-4 (amends TUI-4)
+
+Treatment B, labelled rails: a prominent bordered `q QUIT TUI` rail, visually separate from the monitoring-state block and the paused banner. The footer becomes `p pause · r resume · c collect · d disclosures` — the rail owns quit; the footer carries no quit entry. Quitting the TUI never alters monitoring state. The register's TUI-4 binding parenthetical is amended accordingly by this assembly.
+
+## 5. Launch auth banner — DC-5
+
+A quiet informational line (treatment A) that never competes with drive state:
+
+- Text: `privileged actions will prompt for authentication (polkit)`
+- Full-width under the header at TUI launch; clears on the first refresh tick; never reappears in the session.
+- TUI-only; `fenris status` never shows it.
+- Elevation wording is polkit-accurate everywhere: no user-facing string uses "sudo" (sudo belongs to install/upgrade docs).
+- Evidence class A: a Textual pilot drives refresh ticks headlessly.
+
+## 6. Changelog and release notes — DC-6, DC-7, DC-8
+
+Implements the existing glossary term *Release* (tag + packages + change notes together). No new glossary terms; no ADR (reversible mechanism).
+
+### 6.1 CHANGELOG.md (source of truth, repo root)
+
+- Keep a Changelog 1.1 shape. `## [Unreleased]` is always present at top, even empty. Version headings are `## [X.Y.Z] - YYYY-MM-DD` — bracketed bare semver, strict ISO date.
+- Categories are `### Added`, `### Changed`, `### Fixed` only; security fixes fold into Fixed.
+- Entries are single `- ` bullets, imperative mood, user-facing phrasing; no commit hashes or issue numbers.
+
+### 6.2 Extraction (release.yml, tag time)
+
+- `scripts/extract_changelog.py` (checked in, unit-tested): takes the changelog path and a version; slices that version's section verbatim; never reads `[Unreleased]`. Fails closed — `::error::` plus nonzero exit — when the section is missing or empty or the date is malformed.
+- Guard: the workflow fails when the pushed tag ≠ `v{version from pyproject.toml}` (guard skipped on `workflow_dispatch`).
+
+### 6.3 Release body
+
+- Body = extracted version section verbatim + standing footer from `packaging/release-footer.md` (channel install one-liners, `sha256sum -c SHA256SUMS.asc` verify, rollback pointer). The footer is standing text; only the changelog section varies.
+- Re-run against an existing release: PATCH the body (changelog re-sync is a feature); uploaded assets/packages keep their current idempotent-skip.
+
+### 6.4 Discipline
+
+- All entries land in `[Unreleased]` as part of the fixing change — no notes-later step.
+- One release commit bumps the pyproject version, renames `[Unreleased]` → the version heading, and restores an empty `[Unreleased]`; the tag points at that commit (tag ↔ pyproject ↔ changelog triple-match, enforced fail-closed by DC-7).
+- No backfill: per-release notes begin with the release shipping this mechanism; `CHANGELOG.md` starts with empty `[Unreleased]`.
+
+## 7. String register (verbatim)
+
+### TUI-only strings (launch/identity surfaces)
+
+| Surface | String |
+|---|---|
+| Header bar | `Fenris — NVMe endurance monitor` |
+| Credit (dimmed, inline with service facts) | `by Bongbetic` |
+| Auth banner (full-width under header at launch, clears on first refresh tick, never reappears) | `privileged actions will prompt for authentication (polkit)` |
+| Quit rail (bordered, labelled) | `q QUIT TUI` |
+| Footer (owns key hints; no quit entry) | `p pause · r resume · c collect · d disclosures` |
+
+### Parity strings (TUI and `fenris status` identical — CI-2)
+
+| Surface | String |
+|---|---|
+| Continuity, active + boot enabled | `monitoring: active in background · persists across reboots` |
+| Continuity, boot disabled | `monitoring: does not start on next boot` |
+| Paused state line | `monitoring: paused — deliberate disable` |
+| Paused consequence line | `paused time is excluded from your usage habit · resume: fenris monitor resume` |
+
+`fenris status` prints the paused state line + consequence line when paused, identical wording to the banner title + subline.
+
+## 8. README section (add at execution)
+
+The README gains a "Reading the dashboard" section after the CLI reference. Verbatim text:
+
+```markdown
+## Reading the dashboard
+
+`fenris` opens the TUI dashboard. Three things it tells you:
+
+- **Continuity** — the service strip's continuity line (and `fenris status`) reports whether monitoring survives reboots: `monitoring: active in background · persists across reboots`, or `monitoring: does not start on next boot`.
+- **Paused vs. quit** — a full-width `monitoring: paused — deliberate disable` block means collection is stopped (`fenris monitor pause`); resume with `fenris monitor resume`. Pressing `q` only leaves the screen — monitoring keeps running in the background.
+- **Auth banner** — at launch, `privileged actions will prompt for authentication (polkit)` shows once and clears on the first refresh. Privileged actions elevate via polkit; Fenris never asks for sudo.
+
+Per-release notes live on the [releases page](https://git.bongbetic.com/xavierk/Fenris/releases): each entry is the version's `CHANGELOG.md` section — what was added, changed, and fixed — plus standing install and verification instructions.
+```
+
+This resolves the map's README-wording fog: the wording is decided here; the actual README edit is execution.
+
+## 9. Out of scope
+
+Executing any of this — code, tests, releases — and any TUI layout or information-architecture redesign beyond the five additions named above. Execution is a fresh effort after handoff.

docs/spec/fenris-redesign.md

@@ -0,0 +1,654 @@
+# Fenris redesign specification
+
+**Status: implementation-ready.** Assembled by [Write the Fenris redesign specification and close the map](https://git.bongbetic.com/xavierk/Fenris/issues/19), executing the assembly decision [Assemble the implementation-ready specification](https://git.bongbetic.com/xavierk/Fenris/issues/17) (all seven recommendations accepted) on the Wayfinder map [Chart Fenris's persistent TUI monitoring redesign](https://git.bongbetic.com/xavierk/Fenris/issues/1).
+
+**Canonical roles.** [ADRs 0001–0006](../adr/) are the immutable rationale records — the *why*. [Acceptance criteria](acceptance-criteria.md) are the single register of testable statements — the *definition of done*. This document normatively restates every **operative contract** — the *what* — so an implementer never needs Wayfinder-ticket access: schema column sets, constants, rule tables, unit and CLI definitions, and the Panes TUI layout. Nothing here overrides an ADR or restates a criterion as a criterion.
+
+## How to read this document
+
+- **Binding language.** *Must*, *exactly*, and *never* are normative. Terminology follows the glossary in [`CONTEXT.md`](../../CONTEXT.md): *observation history*, *usage-adjusted theoretical lifespan*, *projection confidence*, *monitoring period*, *observation store*, *hour observation*, *day aggregate*, *controller segment*, *degraded identity*, *endurance baseline*, *verified override*, *unverified override*, *sustained regime*, *habit change*, *scenario range*, *coverage*, *collection run*, *deliberate disable*, *store fault*.
+- **Ordering.** Sections follow data flow: system context → collector acquisition → observation store → controller identity & segmentation → hour/day derivation → projection & confidence → Panes TUI → service lifecycle & sanctioned toggle → failure & recovery → installation. Each section opens with its ADR links and criterion-ID block.
+- **Implementation boundary.** This specification plans the redesign; it does not implement it. The complete handoff is this document + the [criteria register](acceptance-criteria.md) + [ADRs 0001–0006](../adr/) + the glossary. Given/When/Then test specs are derived by the implementer at implementation time.
+
+### Normative constants index
+
+Every constant is defined once, in the section named below; other sections cite, never redefine. All are named constants in code, not configuration.
+
+| Constant | Value | Defined in |
+|---|---|---|
+| Collection cadence (default) | 5 min (`OnUnitInactiveSec`) | §8.2 |
+| First-boot delay | 2 min (`OnBootSec`) | §8.2 |
+| Timer accuracy window | 30 s (`AccuracySec`) | §8.2 |
+| Collection-run timeout | 90 s (`TimeoutStartSec`) | §8.2 |
+| Fresh threshold | newest sample within 2 × cadence + `AccuracySec` + 60 s | §8.9 |
+| Missed → stale boundary | 48 h | §8.9, §6.7 |
+| Powered-off hour threshold | power-on-hours delta < 90 % of the hour's wall-clock span | §5.1 |
+| Active hour threshold | DUW delta ≥ 256 MiB in the hour | §5.1 |
+| Raw-sample retention | 14 days | §3.4 |
+| Warming gate | 14 distinct UTC day aggregates, ≤ 2 below 50 % coverage | §6.6 |
+| Supported coverage floor | 80 % | §6.7 |
+| Horizon agreement | 7/28/90-day rates within a factor of 2 | §6.7 |
+| Burst guard | no single day ≥ 50 % of trailing 28-day bytes | §6.7 |
+| Young-regime cap | regime < 7 days old → Limited | §6.4 |
+| Habit-change trigger | trailing 7-day mean ≥ 2× or ≤ 0.5× the preceding 28-day mean, 3 consecutive days | §6.4 |
+| Regime span cap (default) | full observation history capped at 90 days | §6.4 |
+| Scenario horizons | 7 / 28 / 90 days | §6.5 |
+| Implied-baseline eligibility | ≥ 2 Percentage-Used increments within the current controller segment | §6.3 |
+| Rated-TBW conversion | `E_rated = entered_TBW × 10¹²` bytes | §6.3 |
+| Implied-baseline validity window | 1 ≤ p ≤ 254 | §6.3 |
+| Wear-disagreement note | vendor wear vs. observed write rate by more than a factor of 2 | §6.1 |
+| Capacity validation tolerance | ± 1 % | §6.2 |
+
+---
+
+## 1. System context
+
+**ADRs:** [0001](../adr/0001-observation-store-sqlite.md), [0003](../adr/0003-service-lifecycle-and-sanctioned-toggle.md), [0006](../adr/0006-collector-acquisition-path.md). **Criteria:** CI-3, LC-1, LC-5, ST-1.
+
+### 1.1 Scope
+
+Fenris observes one configured NVMe drive's real-world use and translates the observation history into a usage-adjusted theoretical lifespan. The redesign replaces the HTML dashboard with a keyboard-first TUI backed by a short-lived privileged collector on a systemd timer, persistent compact observation storage, and categorical projection confidence reflecting the length, completeness, and stability of real usage history.
+
+Standing constraints, binding on every section:
+
+- Linux with systemd and polkit only; no other init system is supported.
+- Exactly one configured NVMe drive — the device named by `/etc/fenris/fenris.conf` (§8.3).
+- Fully local: no telemetry, no network fetching, no automatic vendor-data retrieval.
+- The HTML dashboard and HTTP server are gone; nothing of the daemonization, PID files, or `/run` state survives.
+- CLI `status` and `sample` are retained (§8.8).
+
+### 1.2 Components and privilege boundaries
+
+| Component | Privilege | Path | Role |
+|---|---|---|---|
+| `fenris-collect.service` | root oneshot unit | `/usr/libexec/fenris/fenris-collect` | The only code path that interrogates the device and writes the observation store. |
+| `fenris-collect.timer` | system timer | — | Schedules collection runs; `WantedBy=timers.target`. |
+| `fenris-monitor` | root helper | `/usr/libexec/fenris/fenris-monitor` | Fixed privileged operations: `enable`/`disable` (optional `--now`), the collect trigger, monitoring-period bookkeeping, and baseline persistence. The only binary polkit authorizes. |
+| `fenris` | unprivileged | `/usr/local/bin/fenris` | Human entry point: no arguments opens the TUI; subcommands are the CLI (§8.8). Never a unit. |
+| Observation store | root-written, group-read | `/var/lib/fenris/observations.db` | Single SQLite database in WAL mode (§3). The TUI and `status` open it read-only. |
+| Configuration | world-readable | `/etc/fenris/fenris.conf` | Exactly one key: the device selector (§8.3). |
+
+The TUI and CLI are ordinary unprivileged processes. Elevation is exclusively polkit, exclusively for `fenris-monitor` (§8.5). There is no `/run/fenris` coordination surface and no export layer: systemd serializes collection runs, the observation store holds state, failures go to the journal.
+
+### 1.3 Data flow
+
+1. The timer fires; `fenris-collect.service` runs `fenris-collect`.
+2. The collector acquires counters and thermal evidence from `smartctl -a -j` and controller identity from sysfs (§2), normalizes identity exactly once (§2.3), and either fails the whole run or writes one complete sample.
+3. The collector derives and validates hour observations and day aggregates, advances controller segmentation and period bookkeeping, prunes raw samples, and commits (§3–§5, §9.1).
+4. Readers — the TUI and `fenris status` — open the store read-only and **recompute the projection on every read** (§6); nothing derived is ever stored (§3.7).
+
+Control flow is separate: the human drives the TUI/CLI; privileged operations route through `fenris-monitor` under polkit to `systemctl`; period rows record *intent* (only the sanctioned path), while the collector records *observed fact* (§8.5–§8.6, §9.8).
+
+### 1.4 Cross-cutting prohibitions
+
+These are operative contracts; each is restated in its home section and gated by the criteria block [CI-3](acceptance-criteria.md):
+
+1. No code path outside `fenris-collect` interrogates the device (§2.1, §8.7).
+2. Polkit authorizes exactly one binary, `fenris-monitor`, under `com.bongbetic.fenris.monitor` `auth_admin` (§8.5).
+3. No `/run/fenris` coordination surface or export layer exists (§1.2).
+4. No absent hour is ever interpolated, estimated, or fabricated (§5.3, §9.3).
+5. No alerting, notification, or escalation machinery exists anywhere (§9.6–§9.7).
+6. `/etc/fenris/fenris.conf` holds exactly one key — the device selector (§8.3).
+7. No synthetic or capacity-derived baseline is ever created, including for legacy history (§6.1, §3.5).
+8. Readers never partially interpret a newer-schema store (§3.6, §9.5).
+9. Projections are never stored; always recomputed on read (§3.7, §6.10).
+
+---
+
+## 2. Collector acquisition
+
+**ADR:** [0006](../adr/0006-collector-acquisition-path.md). **Criteria:** AC-1–AC-5; miss absorption per [0005](../adr/0005-failure-detection-and-recovery.md) §5.
+
+### 2.1 Channels — the hard pin
+
+Every collection run acquires exactly two ways:
+
+- **Counters and thermal evidence** — solely from `smartctl -a -j <device>`: `data_units_written`, `data_units_read`, `percentage_used`, `available_spare`, `media_errors`, `power_on_hours`, `power_cycles`, `unsafe_shutdowns`, temperature, `critical_warning` — consumed as-is (smartmontools already trims the strings it copies).
+- **Controller identity** — solely from sysfs (`/sys/class/nvme/<ctrl>/`): `subnqn`, `sn`, `mn`, `fr`, `transport`.
+
+No other acquisition path exists anywhere in the codebase. There is no fallback: libnvme bindings and the `nvme` CLI JSON interface are excluded (ADR 0006, *Considered options*).
+
+### 2.2 All-or-nothing runs
+
+Any acquisition failure — missing `smartctl` binary, nonzero exit, malformed JSON, unreadable sysfs attribute — fails the **whole** collection run. A partial sample (identity without counters, or counters without identity) is never written: a transient read failure must never push a healthy drive down the degraded-identity path (§4). The miss surfaces through freshness grading (§8.9) and the flat retry cadence (§9.6), never as degraded identity.
+
+### 2.3 Identity normalization — once, at write time
+
+One collector-side function normalizes every identity field, applied exactly once at write time:
+
+- strip trailing spaces and newlines;
+- no case folding;
+- empty-after-strip is stored blank.
+
+Padded and unpadded renderings of the same field therefore yield byte-identical stored values — a collector implementation change can never split a drive's own history. A future acquisition-path change must deliver byte-identical normalized identity values, or the change itself forces a controller-segment boundary.
+
+### 2.4 Segment metadata sourcing
+
+`transport` comes from the NVMe class sysfs directory. `vid`/`ssvid` come from the PCI node (`/sys/class/nvme/<ctrl>/device/{vendor,subsystem_vendor}`) when present and are stored null otherwise. Both are segment **metadata only** (§4.2), never key components.
+
+### 2.5 Prerequisites
+
+`make install` verifies `smartctl` is present and fails cleanly otherwise (§10.1). The acquisition path adds no Python dependency and no OS package beyond smartmontools; the dependency lockfile (§10.5) is untouched by this section.
+
+---
+
+## 3. Observation store
+
+**ADR:** [0001](../adr/0001-observation-store-sqlite.md) as amended by [Define endurance-baseline provenance and validation](https://git.bongbetic.com/xavierk/Fenris/issues/12) and [Decide controller-segment metadata columns](https://git.bongbetic.com/xavierk/Fenris/issues/14). **Criteria:** ST-1–ST-12; FL-5.
+
+### 3.1 Substrate and access
+
+- One SQLite database in **WAL mode** at `/var/lib/fenris/observations.db`. An unprivileged reader querying during a collector write sees a consistent snapshot.
+- The database is root-owned and group-readable through the `fenris` read group created by packaging; the TUI and `status` open it **read-only**. No `/run` snapshot, no export layer.
+- `/var/lib/fenris` is created by the installer with root-written group-read permissions; the database file itself is created lazily by the first write, so "no observations yet" remains a real state the TUI can greet (§7.6, §10.1).
+- Migration, schema changes, prune, and import are each single transactions — a killed timer run can never leave partial state.
+
+### 3.2 Entities and column sets
+
+The schema carries exactly six entities:
+
+**`samples`** — recent raw samples (14-day retention, §3.4): timestamp (UTC); the normalized controller-identity fields captured at acquisition (§2.3); raw integer `data_units_written`, `data_units_read`; `percentage_used`; `available_spare`; `media_errors`; `power_on_hours`; `power_cycles`; `unsafe_shutdowns`; temperature; `critical_warning`.
+
+**`hour_observations`** — one row per UTC hour: the usage-habit split `seconds_active`, `seconds_idle`, `seconds_powered_off`, `seconds_unknown` (summing to 3600, §5.1); DUW/DUR deltas; temperature min/avg/max; sample count; coverage flag. Classification thresholds belong to the projection model (§5.1), not the store.
+
+**`day_aggregates`** — one row per UTC day, the habit-evidence grain: each day row carries, at minimum, the day's activity-split sums, write deltas, and coverage share — the inputs the evidence gates of §6.6 consume — derived monotonically from its hour rows.
+
+**`monitoring_periods`** — `started_at`; `ended_at` (NULL = open); `end_cause` enum (`user_disabled`, `migrated`, …). Powered-off time stays inside a period; deliberately disabled time does not (§5.2, §8.6).
+
+**`controller_segments`** — spans of unchanged controller identity and monotonic counters; write deltas are never computed across a segment boundary. Columns: the identity key (§4.1) and the frozen metadata snapshot of §4.2, plus the segment's span bounds.
+
+**`endurance_baseline`** — one active row, replaced on edit (§6.2): the rated-TBW value in bytes (`E_rated = entered_TBW × 10¹²`); mandatory provenance — source URL, document revision, entry date, model string, nominal capacity; frozen validation facts — detected model, detected capacity bytes, `validated_by` (`machine`/`user`), `validated_at`.
+
+### 3.3 Time model
+
+Hours and days are UTC-bounded. Day derivation from hour rows is monotonic; DST-ambiguous 23- or 25-hour days never exist in the store.
+
+### 3.4 Retention
+
+Raw samples are pruned opportunistically by the collector to **14 days**. Hour observations and day aggregates are retained indefinitely.
+
+### 3.5 Legacy migration
+
+The migration procedure, invoked from the entry points below, is **idempotent and interruption-safe**:
+
+1. If the store already carries the legacy-import marker, do nothing.
+2. `history.jsonl` is the sole authority: import raw samples and derive hour observations and day aggregates from them.
+3. `hourly.jsonl` is never trusted as input: mismatches against derived data are diffed and logged.
+4. Open one implicit `monitoring_periods` row at the first legacy sample, closed `end_cause = migrated` at the migration moment. Pre-migration hours carry an unknown activity split except directly evidenced facts — a sample present means powered on; a DUW delta means writes occurred.
+5. The import is a single transaction: a scripted kill mid-import leaves the store fully pre- or fully post-migration.
+6. Only after commit are legacy files renamed `*.migrated` — never deleted.
+7. Malformed legacy lines are quarantined with a logged count, never silently dropped.
+
+No synthetic or capacity-derived baseline is ever created for legacy history (§1.4–7). Entry points: the installer's import detection at `./data/history.jsonl` (or an explicit path) (§10.1); `fenris import <path>` for later finds (§8.8); and the collector's first new-version run, which performs this same procedure (ADR 0001 §6).
+
+### 3.6 Schema versioning
+
+`PRAGMA user_version` plus ordered migration steps in code, each in its own transaction. The collector refuses to run against an unknown **newer** version; readers refuse symmetrically with the exact wording of §9.5 and never partially interpret. *Reconciliation note:* ADR 0004 §6 describes upgrade-time migrations as "governed by a `schema_version` table" — the operative mechanism is this section's `user_version` (ADR 0001 §8, criterion ST-12); there is one version authority, not two.
+
+### 3.7 Nothing derived is stored
+
+Projections are not stored; there is no separate latest-status table and no stored health flag. The freshest sample timestamp is the store's own staleness signal (§8.9). The baseline lives in the database (§6.2); `/etc/fenris/` holds only operational configuration (§8.3).
+
+---
+
+## 4. Controller identity and segmentation
+
+**Decisions:** [Verify the controller identity that segments observation history](https://git.bongbetic.com/xavierk/Fenris/issues/11), [Decide controller-segment metadata columns](https://git.bongbetic.com/xavierk/Fenris/issues/14), [Decide how degraded identity affects projection confidence](https://git.bongbetic.com/xavierk/Fenris/issues/15). **ADRs:** [0001](../adr/0001-observation-store-sqlite.md) §3 (as amended), [0002](../adr/0002-projection-model-sustained-regime.md) §§8–9 (as amended). **Criteria:** ID-1–ID-4, PR-9, PR-15, PR-16.
+
+### 4.1 Identity key ladder
+
+The controller-segment identity key is the **normalized, kernel-exposed subsystem NQN** (`subnqn`), with fallbacks, in order:
+
+1. kernel-exposed subsystem NQN;
+2. the kernel composite;
+3. `model|serial`.
+
+`fr` (firmware revision) is metadata only — it may go stale after a mid-segment firmware update. Identity change and DUW decrease are **independent axes** (§4.3).
+
+### 4.2 Frozen metadata snapshot
+
+Each segment freezes, at open, a fully nullable metadata snapshot — immutable thereafter: normalized `subnqn`, `sn`, `mn`, `fr`, plus `vid`, `ssvid`, `transport`, and the `identity_degraded` flag. All columns are nullable so incompleteness stays explicit: legacy-imported segments carry `mn` with NULLs (§4.4); degraded segments carry whatever was observed. These are human diagnostics, never key components. `cntlid` is excluded — it distinguishes controllers within one subsystem, out of scope for a single-drive monitor.
+
+### 4.3 Segmentation axes
+
+- **DUW decrease, unchanged identity** — a segment boundary within the same drive. Prior day aggregates remain habit evidence; the projection is Unavailable only until the new segment re-warms (§6.8).
+- **Identity-key change** — quarantines prior history from projection entirely: it describes a different drive (§6.8).
+- **Degraded identity** — a segment whose identity key is **blank** (every rung of the ladder empty). `identity_degraded` is set at segment open exactly when the key is blank; keys from the kernel-composite or `model|serial` rungs are not degraded. Blank-key semantics extend identity-change rules verbatim: any visible change of the recorded key — including to or from blank — is a controller-identity change and quarantines; equal blank keys continue the segment, segmented by DUW monotonicity alone. Even a degraded→healthy transition quarantines, so the projection window only ever spans segments sharing one key (§6.8).
+- Ephemeral markers (model "Linux", non-pcie transport) are segment metadata, never confidence facts.
+
+The confidence consequence of degraded identity — capped at Limited with its fixed contributing fact — is §6.7's rule.
+
+### 4.4 Legacy identity
+
+Legacy history imports under a labeled, model-scoped **legacy identity** (mn-only segments), so it never blends with the post-redesign identity of the same physical drive.
+
+---
+
+## 5. Hour and day derivation
+
+**ADRs:** [0002](../adr/0002-projection-model-sustained-regime.md) §§4–6; [0001](../adr/0001-observation-store-sqlite.md) §3; [0003](../adr/0003-service-lifecycle-and-sanctioned-toggle.md) §2 (power-on-hours evidence). **Criteria:** PR-4–PR-6, ST-4, FL-3.
+
+### 5.1 Hour classification
+
+Each UTC hour is classified by named constants, in this order of evidence:
+
+- **Powered-off** — the hour's power-on-hours delta is below **90 %** of its wall-clock span.
+- **Active** — DUW delta ≥ **256 MiB** in the hour.
+- **Idle** — powered on, sampled, below the active threshold.
+- **Unknown** — everything else: unsampled without power-on-hours evidence (machine-off and collector failure are indistinguishable by design), or inconsistent counters.
+
+There is no configuration surface for these thresholds; they are documented constants in one projection module.
+
+### 5.2 Denominator and disabled time
+
+The projection denominator is **wall-clock seconds inside monitoring periods**, including powered-off and unknown time. Disabled periods — wall-clock outside monitoring periods — are excluded from numerator and denominator. **Disabled time is not an hour state.**
+
+### 5.3 Gaps and coverage — never backfill
+
+No absent hour is ever interpolated, estimated, or fabricated. Unexplained gaps inside a period keep the aggregate counter delta, remain in the denominator as unknown seconds, and reduce coverage. Power-on-hours classification (§5.1) is the only inference admitted. **Coverage** is the share of wall-clock seconds inside monitoring periods whose classification is known rather than unknown — a first-class displayed fact (§6.10, §7.3).
+
+### 5.4 Day aggregates
+
+One row per UTC day, derived monotonically from hour rows (§3.2–§3.3) — the grain at which usage-habit evidence is judged (§6.6).
+
+---
+
+## 6. Projection and confidence
+
+**ADRs:** [0002](../adr/0002-projection-model-sustained-regime.md) as amended by [Decide how degraded identity affects projection confidence](https://git.bongbetic.com/xavierk/Fenris/issues/15); baseline per [Define endurance-baseline provenance and validation](https://git.bongbetic.com/xavierk/Fenris/issues/12). **Criteria:** PR-1–PR-17, CI-4.
+
+### 6.1 One projection; baseline precedence
+
+Exactly **one** usage-adjusted theoretical lifespan is computed, against the endurance baseline chosen by precedence:
+
+1. **Verified override** — a rated-TBW override with complete provenance whose applicability to the detected drive was confirmed by machine match or explicit user attestation;
+2. **Unverified override** — a rated-TBW override knowingly stored with incomplete provenance; always presented as user-supplied, never as verified;
+3. **Implied baseline** — derived from vendor wear (§6.3), eligible only per §6.3's gate;
+4. otherwise the projection is **Unavailable**.
+
+Percentage Used is context, never a second projection: it renders as a vendor-wear context line, and when the wear it implies disagrees with the observed write rate by more than a factor of 2, a note says so. The legacy PU-slope regression and `capacity × 600` synthesis are gone; no synthetic or capacity-derived baseline is ever created (§1.4–7).
+
+### 6.2 Endurance baseline: provenance and validation
+
+The baseline lives in the observation store's `endurance_baseline` table (§3.2) and is edited via the CLI (§8.8) — `/etc/fenris/` holds no baseline.
+
+- **Mandatory provenance:** source URL, document revision, entry date, model string, nominal capacity.
+- **One active row**, replaced on edit.
+- **Verification is derived at read** — complete provenance and a drive match (machine or attested) — never a stored boolean.
+- **Unverified tier:** incomplete provenance stores only behind an explicit unverified acknowledgment, as NULL fields in that precedence tier.
+- **Entry-time validation** (unprivileged, live sysfs read of the configured device): normalized model containment, with an interactive confirm recorded as `validated_by = user`; nominal capacity within ± 1 %.
+- **Read-time applicability:** a model match against the current controller segment (§4). A mismatch is **retained — never auto-deleted** — and leaves the projection Unavailable.
+- Persistence goes through the polkit-guarded `fenris-monitor` verb after CLI-side validation (§8.5).
+
+### 6.3 Arithmetic
+
+```text
+rate          = regime DUW delta bytes / in-period wall-clock seconds
+projected     = max(E_baseline − W_t, 0) / rate      (rate > 0)
+E_rated       = entered_TBW × 10¹² bytes
+E_implied     = 100 · W_t / p                         (1 ≤ p ≤ 254)
+```
+
+- `E_rated` is exact: rated TBW converts to bytes by × 10¹².
+- `E_implied` is computed **only** for `1 ≤ p ≤ 254`; Percentage Used of 0 or saturated 255 implies no baseline — that precedence tier is unavailable. The implied baseline is labeled *implied from vendor wear estimate* and shown with few significant digits.
+- **Implied-baseline eligibility:** the implied tier is used only after ≥ 2 Percentage-Used increments within the current controller segment; until then the projection is Unavailable with the fixed phrase *"vendor wear estimate too coarse to imply endurance"*.
+
+### 6.4 Sustained regime and habit change
+
+The headline rate is the **sustained-regime** rate: regime DUW bytes ÷ in-period wall-clock seconds. The default regime is the full observation history capped at **90 days**.
+
+A **habit change** is declared when the trailing 7-day mean of daily written bytes stays ≥ 2× (or ≤ 0.5×) the mean of the preceding 28 days for **3 consecutive days**. The new regime starts at the **first day of divergence**, is adopted automatically, and is labeled *"usage habit changed N days ago"*; the scenario range keeps the longer horizons visible. A regime younger than **7 days** caps projection confidence at Limited evidence.
+
+### 6.5 Scenario range
+
+The 7-, 28-, and 90-day rates are computed **independently of the regime** and shown as the scenario range. Only horizons the history actually covers appear — no placeholders. The scenario range is the only spread shown anywhere (§6.9).
+
+### 6.6 Minimum evidence
+
+Warming up until **14 distinct UTC day aggregates** of which at most **2** fall below 50 % coverage. The projection still renders while warming up, labeled with its facts (e.g. *"warming up: N of 14 qualifying days"*). Every Unavailable condition renders **no lifespan number**.
+
+### 6.7 Confidence rule table
+
+Confidence renders as **state plus contributing facts, never a percentage**. Three states:
+
+- **Unavailable** — no applicable baseline; DUW unsupported; zero rate over the regime; controller-identity change.
+- **Supported** — verified baseline **and** ≥ 14 qualifying days **and** coverage ≥ 80 % **and** fresh (< 48 h) **and** 7/28/90 rates within a factor of 2 across existing horizons **and** no single day ≥ 50 % of trailing 28-day bytes **and** regime ≥ 7 days old **and** the current controller segment's identity key is not degraded.
+- **Limited** — every other case with a baseline and a positive rate; the failing facts are shown.
+
+**Staleness:** a newest day aggregate older than **48 hours** drops confidence one level (Supported → Limited) and is shown as a contributing fact.
+
+**Degraded identity:** a controller segment whose identity key is blank (§4.3) caps confidence at **Limited evidence**, with the contributing fact *"controller identity unavailable — replacement detection relies on write-counter continuity only"* rendered in every state. Supported is unreachable while the current segment is degraded. The cap combines idempotently with the staleness drop (both land at Limited).
+
+### 6.8 Segment-break effects
+
+- **DUW decrease, unchanged identity:** prior day aggregates remain habit evidence; the projection is Unavailable only until the new segment re-warms (§6.6).
+- **Controller-identity change** — including any to-or-from-blank key change (§4.3): prior history is quarantined from projection entirely.
+- Since even degraded→healthy transitions quarantine, the projection window only ever spans segments sharing one key; no cross-segment propagation rule is needed.
+
+### 6.9 Zero rate and uncertainty
+
+Zero rate renders *"no finite projection from this history"* — never infinity, never zero. No statistical confidence interval appears anywhere; the scenario range is the only spread.
+
+### 6.10 The projection contract
+
+The projection function hands the TUI and `status` exactly: the confidence state; the contributing facts — including the degraded-identity fact when the current segment's key is blank; the headline remaining time when one exists; the scenario range; the Percentage-Used context line; the disclosure text (§6.11). Recomputed on read, never stored.
+
+### 6.11 User-facing language
+
+Adopted from the endurance research as fixed by ADR 0002 §12; rendered identically by TUI and `status`.
+
+**Headline wording** (equivalent phrasing required):
+
+> Estimated time until the selected host-write endurance baseline is consumed, if future write usage resembles the observed usage habit. This is not a predicted hardware-failure date.
+
+**Fixed phrases** (exact): *no finite projection from this history* (zero rate); *vendor wear estimate too coarse to imply endurance* (§6.3); *usage habit changed N days ago* (§6.4); *controller identity unavailable — replacement detection relies on write-counter continuity only* (§6.7); *observation store unreadable* (§9.4); *observation store written by a newer Fenris — upgrade Fenris* (§9.5); *no observations yet* with an enable hint (§8.9); *configuration error: ⟨reason⟩* (§8.3).
+
+**Confidence rendering:** state plus contributing facts, in the research's evidence style, e.g.
+
+> Supported evidence · verified manufacturer TBW · 42 calendar days · 96 % interval coverage · 6 weekly cycles · recent and 28-day rates agree
+
+Never "82 % confidence" or "95 % accurate".
+
+**The six disclosures** (verbatim, always available — TUI disclosures view and `status`):
+
+1. This is an endurance projection, not a predicted hardware-failure date.
+2. Percentage Used is vendor-specific; 100 means estimated endurance consumed but may not mean failure, it can exceed 100, and 255 is saturated.
+3. Rated TBW can be a warranty/endurance threshold with separate time and eligibility terms, not a failure threshold.
+4. DUW is upward-rounded host writes excluding metadata and selected commands, not exact physical NAND writes.
+5. Projection quality depends on baseline provenance, history duration and completeness, recentness, stability, and representative usage cycles; future workload and firmware behavior remain outside the observed evidence.
+6. Gaps can preserve an aggregate counter delta without preserving hourly timing; unexplained and deliberately disabled periods must be distinguished.
+
+---
+
+## 7. Panes TUI
+
+**Decisions:** [Prototype the TUI information architecture](https://git.bongbetic.com/xavierk/Fenris/issues/3) (Variant A adopted), [Evaluate Python TUI frameworks](https://git.bongbetic.com/xavierk/Fenris/issues/6) (Textual). **ADRs:** [0003](../adr/0003-service-lifecycle-and-sanctioned-toggle.md) §§8, 10; [0004](../adr/0004-install-upgrade-removal-lifecycle.md) §10. **Criteria:** TUI-1–TUI-4, CI-1, CI-2, CI-4. The [prototype](https://git.bongbetic.com/xavierk/Fenris/src/branch/prototype/tui-information-architecture/prototype/tui-ia) is visual reference only; this section is normative.
+
+### 7.1 Framework and floor
+
+The TUI is built on **Textual**. It runs on Python 3.9+, gated at install time (§10.1) — never a runtime crash. The tty-passthrough mechanism below was validated live under Textual on a real terminal (prototype decision).
+
+### 7.2 Layout — one dense keyboard-first screen
+
+Variant A **Panes**: everything on one screen, no page navigation. The screen is a grid of four regions:
+
+1. **Headline band** — full width, top: the lifespan headline (or its no-projection wording) with its regime line (*"if current habits continue · sustained regime: N days at R GB/day"*); the confidence state with contributing facts; the scenario range.
+2. **Usage-history pane** — left, wider column: the write-history sparkline with ▲ habit-change and ? unexplained-gap markers plus their legend; the habit-split bar with active/idle/powered-off/unknown shares.
+3. **Drive-health and settings pane** — right, narrower column: health facts (model, temperature, spare, media errors, unsafe shutdowns, power-on hours, power cycles, capacity); the vendor-wear context line (Percentage Used · total written of rated — *context, not a second projection*); a read-only settings view (device selector, cadence with drop-in pointer, raw retention, endurance baseline value with its provenance label). Edits happen via CLI / drop-ins, not in the TUI.
+4. **Service strip** — full width, bottom: the four separate service facts (§7.3), the monitoring-period line, the action legend.
+
+Exact proportions, glyphs, and borders follow the prototype's validated arrangement as visual reference; the region arrangement, contents, and bindings above are normative.
+
+### 7.3 Content contracts per region
+
+- **Confidence is evidence:** state plus contributing facts, never a percentage (§6.7); the headline band renders the §6.10 contract in full, including the disclosure affordance (`d`).
+- **Four separate service facts, always:** boot enablement (enabled/disabled) · runtime activity (timer active/inactive) · last collect outcome (ok/FAILED, age, reason) · freshness (fresh/missed/stale with newest-sample age, §8.9). They are never merged into one "service status".
+- **Monitoring-period line:** open-since / closed with end cause; deliberate-disable count where nonzero.
+- The scenario range shows only covered horizons (§6.5); the vendor-wear context line carries the >2× disagreement note when it applies (§6.1).
+
+### 7.4 Keybindings and asymmetry
+
+Production bindings:
+
+| Key | Action |
+|---|---|
+| `p` | Pause — **asks for confirmation** (y pause · n cancel), stating that paused time is excluded from the usage habit while powered-off time would still count. |
+| `r` | Resume — **no confirmation** (benign; friction invites raw-systemctl escapes). |
+| `c` | Collect now — synchronous outcome (§8.7), no confirmation. |
+| `d` | Disclosures — the six disclosures of §6.11. |
+| `q` | Quit. |
+
+No bare start/stop exists anywhere; no page navigation keys exist (variant switching was prototype-only). Framework defaults apply for focus and scrolling otherwise.
+
+### 7.5 Privileged actions and tty passthrough
+
+Pause, resume, collect-now, and baseline operations run through `fenris-monitor` as a **terminal-attached subprocess**: the TUI suspends, the platform polkit agent prompts on the real terminal, and control returns cleanly with the outcome reflected in the service facts. Where no polkit agent exists the operation fails cleanly with the printed root equivalent (§8.5).
+
+### 7.6 State rendering obligations
+
+- From a synthetic observation store, the TUI renders **every** realizable combination of confidence state × freshness grade × baseline tier exactly as the §6.7 rule table and §8.9 constants dictate — headline number only when the rules allow it, contributing facts always, never a percentage (criterion CI-1).
+- Empty store: *"no observations yet"* with an enable hint; the first-run prompt is an opt-in that enables the timer and opens the first period in one step (§10.1, dormant install).
+- A `configuration error: ⟨reason⟩` fact renders when the device selector is invalid (§8.3); a store fault suppresses everything store-dependent (§9.4); a newer schema renders its fixed phrase (§9.5).
+- Every TUI action has a CLI twin with identical outcomes and wording (§8.8, CI-2).
+
+---
+
+## 8. Service lifecycle and sanctioned toggle
+
+**ADR:** [0003](../adr/0003-service-lifecycle-and-sanctioned-toggle.md) as amended by [Define endurance-baseline provenance and validation](https://git.bongbetic.com/xavierk/Fenris/issues/12). **Criteria:** LC-1–LC-10, CI-2, CI-3.
+
+### 8.1 Units
+
+Exactly two system units exist:
+
+- `fenris-collect.timer` — `WantedBy=timers.target`.
+- `fenris-collect.service` — `Type=oneshot`, root, `ExecStart=/usr/libexec/fenris/fenris-collect`; no listener, no UI code.
+
+The TUI and CLI are ordinary unprivileged processes and never units.
+
+### 8.2 Cadence
+
+Shipped defaults: `OnBootSec=2min`, `OnUnitInactiveSec=5min` (measured from run completion; drift accepted because hours are the evidence grain), `AccuracySec=30s`, `Persistent=no` (no suspend catch-up — absent hours classify through power-on-hours evidence, §5.1), `TimeoutStartSec=90s` so a hung device interrogation fails visibly as a bounded failed run retried next interval. Cadence changes are documented drop-ins on the timer unit (`systemctl edit` + daemon-reload); **no interval key exists in configuration**.
+
+### 8.3 Configuration
+
+`/etc/fenris/fenris.conf` holds exactly one key: the **device selector**, a stable `/dev/disk/by-id/…` path (raw nodes accepted with an instability warning), validated at collection time. The oneshot re-reads it every run — there is no reload path. An invalid selector is a bounded failed run (journal + failed unit result, retried next interval); `status` and the TUI also read the world-readable file directly and surface `configuration error: ⟨reason⟩`.
+
+### 8.4 Entry points
+
+Two privileged binaries — `/usr/libexec/fenris/fenris-collect` (device interrogation and store writes; the unit's `ExecStart`) and `/usr/libexec/fenris/fenris-monitor` (fixed operations `enable`/`disable` with optional `--now`, the collect trigger, monitoring-period bookkeeping, and `baseline set`/`baseline clear` persistence for the CLI-validated baseline; the only binary the polkit policy authorizes). One unprivileged `fenris` wrapper (§1.2). Root invokes the helpers directly; unprivileged users go through polkit.
+
+### 8.5 Sanctioned toggle and polkit
+
+- Pause = `fenris-monitor disable --now`; Resume = `enable --now`. Both perform the systemctl operation **and** the monitoring-period bookkeeping in one step. The human-facing twins `fenris monitor pause` / `fenris monitor resume` map to these and always act immediately; pause asks for confirmation in both TUI and CLI, resume does not (§7.4).
+- Polkit action `com.bongbetic.fenris.monitor` (`auth_admin`) covers the toggle **and** the collect trigger **and** baseline persistence — authorizing exactly the one binary `fenris-monitor`.
+- Where no polkit agent exists the operation fails cleanly and prints the root equivalent.
+- This is the **only** sanctioned control path: a raw `systemctl stop`/`disable` never records `user_disabled` — only the sanctioned path records intent (§8.6).
+
+### 8.6 Period-row idempotent matrix
+
+| Situation | Effect on `monitoring_periods` |
+|---|---|
+| First-ever enable | Opens a period at the enable moment (hours before the first successful sample are unknown-but-inside — correct when the device errors). |
+| Resume with an open period (a raw `systemctl stop` intervened) | No row changes; the gap remains inside as unknown seconds. |
+| Resume with no open period | Opens a new row at the resume moment. |
+| Pause with an open period | Closes it `user_disabled` at the pause moment. |
+| Pause otherwise | No-op. |
+| Raw `systemctl stop`/`disable` outside the helper | An unexplained gap, never `user_disabled`. |
+
+### 8.7 On-demand collection
+
+`fenris sample` and the TUI's collect-now route through `fenris-monitor` → `systemctl start fenris-collect.service`, which blocks until the oneshot exits; the outcome (freshness line or journal hint) is reported synchronously. No confirmation is required. No code path outside `fenris-collect` touches the device; the TUI never samples in-process.
+
+### 8.8 CLI surface
+
+| Command | Behavior |
+|---|---|
+| `fenris` (no arguments) | Opens the TUI (§7). |
+| `fenris status` | Read-only composition of the observation store and allow-listed `systemctl show` properties: projection facts, enabled/active, last collect outcome, and a `journalctl -u fenris-collect.service` hint on failure or staleness. Never auto-samples, never prompts. |
+| `fenris sample` | On-demand collection via the helper path (§8.7). |
+| `fenris monitor pause` / `resume` | The sanctioned toggle (§8.5), pause asking confirmation. |
+| `fenris baseline set` / `clear` | CLI-side validation (§6.2), then polkit-guarded persistence. |
+| `fenris import ⟨path⟩` | The idempotent single-transaction legacy import (§3.5). |
+| `--device` | Rejected with a pointer to the configuration file. |
+| `start`, `stop`, `run` | Rejected with one-line migration pointers — never aliased (an alias would silently change meaning). |
+
+`fenris.sh` is retired: not shipped, removed from the repository; the README maps its five menu options to their successors. Headless administration has full parity: every TUI action has a CLI twin (pause, resume, collect-now, baseline set/clear, the status fact set) with identical outcomes and wording.
+
+### 8.9 Freshness grading
+
+Constants defined once, consumed by TUI and CLI alike; the grade derives from the **newest sample timestamp**, never a stored flag:
+
+- **fresh** — newest sample within 2 × cadence + `AccuracySec` + 60 s (11.5 min at default cadence);
+- **missed** — between that and 48 h (a contributing fact);
+- **stale** — ≥ 48 h, matching the §6.7 evidence gate;
+- **empty store** — *"no observations yet"* with an enable hint.
+
+---
+
+## 9. Failure and recovery
+
+**ADR:** [0005](../adr/0005-failure-detection-and-recovery.md). **Criteria:** FL-1–FL-8.
+
+The posture: **visible degradation, never fabrication.**
+
+### 9.1 Write-boundary validation
+
+The collector validates every row it would write against the store's domain invariants: hour seconds sum to 3600; non-negative DUW delta within a controller segment; coverage consistent with sample count. A violating run **writes nothing**, logs the refused row to the journal for post-mortem, and fails visibly — retried next interval. Store invariant: everything persisted is well-formed.
+
+### 9.2 Reader defense
+
+Readers (TUI, `status`) defensively exclude and count malformed rows as a contributing fact. Under a single trusted writer they should never see one.
+
+### 9.3 No backfill, ever
+
+Gaps remain unknown seconds; degradation flows exclusively through coverage, freshness facts, and confidence categories; recovery is the timer's next successful run. Power-on-hours classification (§5.1) is the only inference admitted.
+
+### 9.4 Store faults — degrade, never recreate over
+
+An unreadable or corrupt database is a store fault: readers surface *"observation store unreadable"* with the journal hint and show nothing else that depends on the store; the collector treats it as a bounded failed run and **never recreates or overwrites** an existing file. Recovery is human-sanctioned and documented: back up or move the corrupt file aside; the next run starts a fresh store; if the legacy import never completed, the still-present `history.jsonl` is re-imported (§3.5). No built-in destructive command exists.
+
+### 9.5 Newer schema — symmetric refusal
+
+The TUI and `status` detect a `user_version` newer than they understand and display *"observation store written by a newer Fenris — upgrade Fenris"* without partial interpretation, matching the collector's refusal (§3.6) and the forward-only upgrade rule (§10.2).
+
+### 9.6 Repeated collector failures — flat cadence, no escalation
+
+The timer's retry is the recovery path; the freshness grading walks fresh → missed → stale as failures persist, so degradation is visible without new state. No backoff, no notification machinery; a persistent failure reads as stale exactly like any other gap.
+
+### 9.7 Drive-reported anomalies — facts, not alerts
+
+`critical_warning`, media errors, and unsafe shutdowns surface as ordinary facts in the TUI and `status` (§7.2); no alerting or notification surface exists. The projection is unaffected: endurance math consumes writes, not warnings.
+
+### 9.8 Orphaned samples — the collector re-anchors observed fact
+
+When a collection run finds no open monitoring period (fresh store after a store fault, completed legacy re-import, or first-ever run), it opens one at the **run moment**, never backdated. This records observed fact, not intent — only the sanctioned path records a `user_disabled` close (§8.5). Coverage semantics stay intact without requiring a re-run of `fenris-monitor enable` after recovery.
+
+---
+
+## 10. Installation
+
+**ADR:** [0004](../adr/0004-install-upgrade-removal-lifecycle.md). **Criteria:** IN-1–IN-10.
+
+### 10.1 Install
+
+`sudo make install`:
+
+1. Builds a wheel from the checkout and installs it, with pinned dependencies (§10.5), into the dedicated Fenris-owned venv at `/opt/fenris`; a `/usr/local/bin/fenris` wrapper makes the unprivileged TUI/CLI a PATH command. The checkout is build-time input only — after install, nothing references it.
+2. Verifies `python3 ≥ 3.9` and `smartctl` presence, failing cleanly otherwise (never a runtime crash).
+3. Creates `/var/lib/fenris` with root-written group-read permissions and the `fenris` read group; the database file is created lazily by the first write (§3.1).
+4. Places units in `/etc/systemd/system`, helpers in `/usr/libexec/fenris`, polkit policy under `/usr/share/polkit-1/actions/` — recording **every** placed file in an explicit manifest consumed by upgrade and uninstall (§10.6).
+5. **Never enables or starts units.** A fresh install is fully dormant: units present but disabled, nothing running, no monitoring period. The only opt-in is the sanctioned toggle — `fenris monitor resume` or the first-run TUI prompt — enabling the timer and opening the first period in one step.
+6. Detects `./data/history.jsonl` beside the source (or accepts an explicit path), runs the idempotent single-transaction import (§3.5), and reports imported counts.
+
+### 10.2 Upgrade
+
+`sudo make upgrade` installs the new wheel into the same venv, syncs units and polkit against the manifest (`daemon-reload`; restart the timer only if unit contents changed **and** it is active — safe with `Persistent=no`), leaves timer state untouched, and **never kills an in-flight collection run**: a running oneshot finishes on its mapped interpreter; at worst one old-code run completes to the store. It then applies forward-only observation-store schema migrations (§3.6). `/var/lib/fenris` is never rebuilt.
+
+### 10.3 Rollback
+
+Best-effort by design: before migrations run, the installer snapshots `observations.db` to a one-generation `observations.db.bak`; rollback means reinstalling the previous version and restoring the backup. Automatic schema downgrade does not exist.
+
+### 10.4 Uninstall and purge
+
+- `make uninstall` first performs the sanctioned disable (`fenris-monitor disable --now`) so an open monitoring period closes `user_disabled` — removal is deliberate, and only the sanctioned path records intent — then stops and disables the units and removes the venv, helpers, units, polkit policy, and wrapper, **keeping** `/etc/fenris` and the observation store. Journal entries age out naturally.
+- `make purge` additionally removes configuration and store.
+- Reinstall after uninstall resumes from the preserved observation store; only purge erases history.
+
+### 10.5 Dependencies
+
+Exact pins in a committed lockfile; install and upgrade both install from it. Refreshing pins is an explicit developer step (`make update-deps`, committed), never a side effect of installing. The acquisition path adds no Python dependency and no OS package beyond smartmontools (§2.5).
+
+### 10.6 Placement manifest
+
+Installed artifacts sit only at their fixed locations — units in `/etc/systemd/system`, helpers in `/usr/libexec/fenris`, polkit policy under `/usr/share/polkit-1/actions/`, configuration at `/etc/fenris`, observation store under `/var/lib/fenris`, venv at `/opt/fenris`, wrapper at `/usr/local/bin/fenris` — and every placed file is recorded in the manifest (criterion IN-10).
+
+---
+
+## Appendix A: Traceability matrix
+
+Built as assembly's first step (assembly decision, recommendation 5). Two-way: every ADR section maps to at least one criterion ID; every criterion cites its ADR or ticket.
+
+### A.1 ADR section → criteria
+
+| ADR section | Criteria |
+|---|---|
+| 0001 §1 Substrate | ST-1, ST-2 |
+| 0001 §2 Access | ST-1, CI-3 (/run) |
+| 0001 §3 Entities (incl. #12/#14 amendments) | ST-3, ST-5, PR-13, ID-2, CI-3 (no stored projections) |
+| 0001 §4 Day boundary | ST-4 |
+| 0001 §5 Retention | ST-5 |
+| 0001 §6 Migration | ST-6, ST-7, ST-8, ST-9, ST-10, ST-11 |
+| 0001 §7 Projection inputs | ST-3, PR-14, CI-3 (one-key config) |
+| 0001 §8 Versioning | ST-12, FL-5 |
+| 0001 §9 Collector health | LC-10 |
+| 0002 §1 One projection | PR-1 |
+| 0002 §2 Rate/formulas/regime/scenario | PR-2, PR-17 |
+| 0002 §3 Habit change | PR-3 |
+| 0002 §4 Hour classification | PR-4 |
+| 0002 §5 Denominator | PR-5 |
+| 0002 §6 Minimum evidence | PR-6 |
+| 0002 §7 Staleness | PR-7 |
+| 0002 §8 Confidence table (incl. #15 amendment) | PR-8, PR-15, CI-1, CI-4 |
+| 0002 §9 Segment breaks (incl. #15 amendment) | PR-9, PR-16 |
+| 0002 §10 Implied eligibility | PR-10 |
+| 0002 §11 Uncertainty | PR-11 |
+| 0002 §12 Language | CI-4 |
+| 0002 §13 Contract | PR-12 |
+| 0003 §1 Units | LC-1, CI-3 (/run) |
+| 0003 §2 Cadence | LC-2, LC-3 |
+| 0003 §3 Configuration | LC-4, CI-3 |
+| 0003 §4 Entry points | LC-5, IN-10 |
+| 0003 §5 Sanctioned toggle | LC-6, CI-2, CI-3 |
+| 0003 §6 Period rows | LC-7 |
+| 0003 §7 On-demand collection | LC-8, CI-2, CI-3 |
+| 0003 §8 TUI controls | TUI-1, TUI-2, TUI-4 |
+| 0003 §9 CLI compatibility | LC-9, CI-2 |
+| 0003 §10 Freshness constants | LC-10, CI-1, CI-2 |
+| 0004 §1 Delivery | IN-1 |
+| 0004 §2 Layout and manifest | IN-2, IN-10 |
+| 0004 §3 Privilege | IN-3, CI-3 |
+| 0004 §4 Dormant install | IN-3 |
+| 0004 §5 Legacy import | IN-4 |
+| 0004 §6 Upgrade | IN-5 |
+| 0004 §7 Rollback | IN-6 |
+| 0004 §8 Removal | IN-7 |
+| 0004 §9 Dependencies | IN-8, AC-5 |
+| 0004 §10 Scaffolding and floor | IN-9, TUI-3 |
+| 0005 §1 Malformed observations | FL-1, FL-2 |
+| 0005 §2 Missed observations | FL-3, CI-3 |
+| 0005 §3 Store faults | FL-4 |
+| 0005 §4 Newer schema | FL-5 |
+| 0005 §5 Repeated failures | FL-6 |
+| 0005 §6 Drive-reported anomalies | FL-7, CI-3 |
+| 0005 §7 Orphaned samples | FL-8 |
+| 0006 §1 Pin | AC-1 |
+| 0006 §2 Hard pin, no fallback | AC-3 |
+| 0006 §3 Normalization | AC-2 |
+| 0006 §4 Segment metadata sourcing | AC-4 |
+| 0006 §5 Prerequisites | AC-5 |
+
+### A.2 Ticket decisions → criteria
+
+| Ticket | Criteria |
+|---|---|
+| [Evaluate Python TUI frameworks](https://git.bongbetic.com/xavierk/Fenris/issues/6) | TUI-3 |
+| [Prototype the TUI information architecture](https://git.bongbetic.com/xavierk/Fenris/issues/3) | TUI-1, TUI-2, TUI-4 |
+| [Verify the controller identity that segments observation history](https://git.bongbetic.com/xavierk/Fenris/issues/11) | ID-1, ID-3 |
+| [Define endurance-baseline provenance and validation](https://git.bongbetic.com/xavierk/Fenris/issues/12) | PR-13, PR-14, ST-3 |
+| [Decide controller-segment metadata columns](https://git.bongbetic.com/xavierk/Fenris/issues/14) | ID-2 |
+| [Decide how degraded identity affects projection confidence](https://git.bongbetic.com/xavierk/Fenris/issues/15) | PR-15, PR-16, ID-4 |
+| [Define cross-cutting acceptance criteria](https://git.bongbetic.com/xavierk/Fenris/issues/13) | the register itself |
+| [Assemble the implementation-ready specification](https://git.bongbetic.com/xavierk/Fenris/issues/17) / [Write the Fenris redesign specification and close the map](https://git.bongbetic.com/xavierk/Fenris/issues/19) | this document and this appendix |
+
+### A.3 Criterion → source
+
+Every criterion carries its citation inline in the [register](acceptance-criteria.md): CI-1–CI-4 (ADR 0002 §§6–8, 0003 §§1–10, 0001 §§2–3/8, 0005 §§2/4–6); ST-1–ST-12 (ADR 0001, with ST-3 amended by tickets #12/#14); LC-1–LC-10 (ADR 0003); PR-1–PR-12 (ADR 0002), PR-13–PR-14 (ticket #12), PR-15–PR-16 (ticket #15, ADR 0002 §§8–9 as amended), PR-17 (ADR 0002 §2); ID-1–ID-4 (tickets #11/#14/#15, ADR 0001 §3 as amended); TUI-1–TUI-4 (tickets #3/#6, ADR 0003 §§8/10, ADR 0004 §10); FL-1–FL-8 (ADR 0005); IN-1–IN-10 (ADR 0004, with IN-10 also citing ADR 0003 §4); AC-1–AC-5 (ADR 0006).
+
+### A.4 Assembly result
+
+- **Every ADR 0001–0006 section maps to at least one criterion** — the A.1 table is complete; no orphan sections.
+- **Every criterion cites its ADR or ticket** — verified in the register; no orphan criteria.
+- **Decided-but-uncitered gaps found and filled inline in the register during assembly:** CI-3 bullet (no `/run` coordination surface; ADR 0003 §1, ADR 0001 §2), PR-17 (projection arithmetic; ADR 0002 §2), TUI-4 (normative Panes layout and bindings; ticket #3), IN-10 (fixed artifact placement; ADR 0004 §2, ADR 0003 §4).
+- **No genuinely undecided behavior remained** — no blocking ticket was raised.
+- **One reconciliation:** ADR 0004 §6's "`schema_version` table" wording resolves to ADR 0001 §8's `PRAGMA user_version` as the single version authority (§3.6); criterion ST-12 already fixed the mechanism.

docs/spec/native-void-support.md

@@ -0,0 +1,66 @@
+# Native Void Linux and XBPS distribution
+
+Status: Approved and published as [Support native Void Linux and signed XBPS distribution through Gitea](https://git.bongbetic.com/xavierk/Fenris/issues/82).
+
+## Problem Statement
+
+Void users cannot install and operate Fenris natively through XBPS because its runtime lifecycle assumes systemd and its release pipeline only produces Debian and RPM packages. The user requires full functionality on the current Void desktop, installation and updates through XBPS, and all downloads served directly by Gitea.
+
+## Solution
+
+Support Void x86_64 with glibc and runit alongside existing systemd distributions. Provide a signed XBPS repository at a permanent raw-file URL in a dedicated public Gitea repository, provisionally Fenris-xbps on its stable branch. Publish versioned assets and notes in the application's Gitea release. Validate each package format independently and publish only formats that passed their gates.
+
+## User Stories
+
+1. As a Void user, I want to install Fenris through XBPS so package ownership and dependencies are managed normally.
+2. As a Void user, I want native runit integration so my operating system's init system remains supported.
+3. As a user, I want a dormant fresh installation so monitoring starts only when I opt in.
+4. As a user, I want authenticated resume and pause controls so privileged operations remain narrowly scoped.
+5. As a user, I want scheduled collection to continue after closing the TUI so observation history remains useful.
+6. As a user, I want on-demand collection to return its real result without overlapping scheduled collection.
+7. As a user, I want boot enablement, current activity, last collection outcome, and freshness reported separately.
+8. As a user, I want actionable native diagnostics when collection fails.
+9. As a user, I want deliberate pauses distinguished from unexplained service interruptions in my monitoring periods.
+10. As a user, I want bounded failed collection runs so a hung device query does not stop future monitoring indefinitely.
+11. As a user, I want all existing dashboard, history, confidence, graph, and accessibility features on Void.
+12. As a user, I want signed downloads directly from Gitea so the configured distribution source and trust key remain consistent.
+13. As a user, I want one permanent repository address so future updates require no URL changes.
+14. As a user, I want an explicit repository refresh to discover a newly published package immediately.
+15. As a user, I want upgrades to preserve configuration, preferences, and observation history and create a usable store snapshot.
+16. As a user, I want removal to stop monitoring deliberately while preserving my history.
+17. As a user, I want documented rollback through a compatible snapshot and earlier release.
+18. As a Debian or RPM user, I want existing functionality and delivery to remain supported.
+19. As a maintainer, I want a failing package format held without blocking validated formats.
+20. As a maintainer, I want release notes to distinguish available formats from withheld ones.
+21. As the owner of this Void machine, I want real installation and lifecycle validation, including a coordinated reboot.
+22. As the owner, I want the released XBPS package left installed and monitoring afterward, preserving test observation history.
+
+## Implementation Decisions
+
+- Amend the existing systemd-only service contract to support native runit while retaining its external semantics. Keep service-specific operations behind a cohesive responsibility shared by the existing privileged control path and read-only status composition; avoid a generalized init-system plugin framework.
+- Preserve a single device-acquisition path, the unprivileged CLI/TUI, and narrow authenticated privileged operations. Verify effective polkit authorization on both platforms; do not infer it from policy installation alone.
+- Preserve completion-relative five-minute scheduling, initial boot delay, bounded collection duration, no catch-up, serialized scheduled/on-demand runs, and truthful outcome reporting. Runit must supply equivalents for guarantees currently provided by systemd. Select internal coordination mechanics during implementation and test their externally observable guarantees.
+- Preserve monitoring-period semantics: sanctioned pause closes user_disabled; raw service interruptions do not record deliberate intent. Preserve separate boot-enabled and runtime-active facts.
+- Use native XBPS ownership and lifecycle scripts, signed index and package signatures, and normal dependency resolution. Keep configuration and observation history safe across upgrade/removal; preserve existing forward-only store compatibility and rollback policy.
+- Host ordinary Git blobs without LFS in the dedicated Gitea repository. Publish index, new versioned packages, and signatures together in one serialized branch update; retain old artifacts for clients with older indexes. Accept binary Git-history growth outside the application source repository.
+- Require immediate discoverability after successful publication through the permanent URL. Test clients that fetched the previous index first. Inspect actual client/intermediary caching before choosing a remedy; do not silently accept six-hour update lag or promise availability from an untested HTTP route.
+- Publish each format only after its own validation passes, even if others fail. Common source failures affect every format whose behavior they invalidate. Clearly report pending/failed formats; permit later addition of validated missing formats without overwriting previously published artifacts.
+- Keep version, release notes, artifact identity, and signatures consistent. Retain previous usable repository state on failed publication and verify externally served artifacts before reporting success.
+- First Void target is x86_64/glibc. Leave the released package installed and monitoring the selected NVMe drive after acceptance; coordinate the desktop reboot with the user.
+
+## Testing Decisions
+
+- Primary runtime boundary: existing user commands and shared CLI/TUI observable state, backed by disposable observation stores and controlled service/acquisition outcomes. Test behavior, not a particular helper layout.
+- Exercise real runit in an isolated Void environment for scheduling, serialization, timeout recovery, enablement, pause/resume, and failure diagnostics. Preserve meaningful systemd regression coverage.
+- Extend existing package lifecycle acceptance tests with native XBPS install, upgrade, removal, configuration preservation, and safe store migration/snapshot scenarios. Use disposable stores for destructive removal/rollback cases.
+- Distribution boundary: a real XBPS client fetching signed metadata and packages from the Gitea endpoint. Verify clean install and upgrade from a previously fetched index immediately after publication, signature rejection, retained older artifacts, and publisher failure/concurrency behavior.
+- Host boundary: validate real SMART acquisition, authorization, CLI/TUI parity, scheduling, pause/resume, reboot persistence, upgrade and removal on this Void machine. Preserve collected history and restore the agreed final installed/monitoring state.
+- Record actual outcomes, skips, and environment failures. Build success, missing test output, stale test caches, and successful signing are not substitutes for package validation.
+
+## Out of Scope
+
+Musl, other architectures, additional init systems, official Void repository inclusion, a separate download server, automatic client upgrades, unrelated dashboard redesign, and automatic downgrade of a newer observation store.
+
+## Further Notes
+
+The design decisions are recorded in ADR 0008. Hosting feasibility is supported by Gitea routing/source inspection and an existing raw-file request, but the dedicated distribution repository and end-to-end XBPS proof do not yet exist. Current host inspection found Void x86_64/glibc with runit, polkit support and an NVMe controller; Fenris and smartmontools were absent. Verify these facts again before host changes.

docs/spec/native-void-tickets.md

@@ -0,0 +1,71 @@
+# Native Void implementation tickets
+
+Status: Approved and published as Gitea issues 83–87 with native blocking edges and ready-for-agent labels. Parent specification: https://git.bongbetic.com/xavierk/Fenris/issues/82.
+
+Each issue references the published native Void specification, which includes ADR 0008. Existing Debian/RPM behavior, observation-history preservation, narrowly scoped privilege, and independent publication gates apply throughout.
+
+Published tickets: [1](https://git.bongbetic.com/xavierk/Fenris/issues/83), [2](https://git.bongbetic.com/xavierk/Fenris/issues/84), [3](https://git.bongbetic.com/xavierk/Fenris/issues/85), [4](https://git.bongbetic.com/xavierk/Fenris/issues/86), [5](https://git.bongbetic.com/xavierk/Fenris/issues/87).
+
+## 1. Prove signed XBPS installation and immediate updates through Gitea
+
+Blocked by: None.
+
+Deliver a dedicated public Gitea distribution repository and a repeatable, isolated XBPS-client proof using clearly identified test artifacts, without representing them as a validated Fenris release.
+
+- Verify permanent raw URL delivery of index, package and signature bytes without LFS indirection.
+- Establish signing-key handling and trust verification without exposing private keys.
+- Demonstrate install and update with a client that fetched the old index immediately before publication.
+- Resolve actual cache behavior and verify binary size limits; escalate any hosting change outside the agreed Gitea scope.
+- Publish index/artifacts together with serialized updates, preserve older downloadable artifacts, and demonstrate safe failure recovery.
+- Record results and the usable publication mechanism for subsequent tickets.
+
+## 2. Run and control Fenris monitoring natively under runit
+
+Blocked by: None.
+
+Deliver an end-to-end native monitoring path with existing CLI/TUI controls and truthful status in an isolated Void environment.
+
+- Scheduled and on-demand collection use the same acquisition path with no overlap and bounded execution.
+- Preserve cadence, initial boot delay, recovery after failures, and no catch-up semantics.
+- Resume/pause preserve monitoring-period bookkeeping and boot/runtime distinctions; raw service stops do not record deliberate disable.
+- Verify effective authentication and actionable native diagnostics, including missing-agent failures.
+- Preserve systemd behavior and application feature parity through existing public behavior tests.
+
+## 3. Install, upgrade and remove Fenris with native XBPS packages
+
+Blocked by: 2.
+
+Deliver buildable x86_64/glibc XBPS artifacts with dependency resolution and tested package lifecycle in an isolated Void environment.
+
+- Fresh install remains dormant; native controls enable monitoring afterward.
+- Package ownership, configuration preservation, permissions, and group access support real CLI/TUI reads and collector writes.
+- Upgrade snapshots and migrates observation history safely without recording a deliberate pause.
+- Removal performs sanctioned pause and retains history; reinstall and documented snapshot rollback behave correctly.
+- Installation over incompatible unmanaged remnants fails with a useful migration path.
+- Capture explicit lifecycle test results and verify Debian/RPM regressions relevant to changed packaging.
+
+## 4. Publish validated package formats independently from the release workflow
+
+Blocked by: 1, 3.
+
+Deliver a release workflow that builds, validates, signs and publishes XBPS alongside existing Debian/RPM support with independent format gates.
+
+- Unvalidated formats remain withheld while validated formats can ship.
+- Notes accurately identify available and withheld formats; source version, notes, checksums and artifacts agree.
+- A withheld format can be added after validation without replacing existing published artifacts.
+- Gitea serves every download; XBPS uses the proven permanent repository URL and immediate-refresh behavior.
+- Release failure/concurrency cannot expose an index referencing missing artifacts or erase the prior usable channel.
+- Host acceptance remains a required XBPS release gate, not bypassed by build/signature success.
+
+## 5. Validate and release on the user's Void machine
+
+Blocked by: 4.
+
+Deliver recorded host acceptance and the validated XBPS release, ending with Fenris installed and monitoring.
+
+- Recheck host state, identify/configure the intended NVMe drive, and preserve pre-existing data before package lifecycle operations.
+- Verify real acquisition, authenticated controls, scheduling, failure reporting, full dashboard behavior, and pause/resume semantics.
+- Coordinate and verify reboot persistence; absence of the reboot test leaves that gate pending.
+- Verify native upgrade/removal/reinstall with history preservation and immediate update discovery through Gitea.
+- Publish only after the XBPS gate passes, then verify downloads and released-package installation.
+- Preserve acceptance-test observation history and leave the released package monitoring; document installation, trust setup, diagnostics and rollback for Void users.

docs/spec/release-packaging.md

@@ -0,0 +1,106 @@
+# Fenris release and packaging specification
+
+**Status: decision-complete.** Assembled by [Task: Compose release spec + ADR amending 0004](https://git.bongbetic.com/xavierk/Fenris/issues/42) from the closed tickets of the Wayfinder map [Fenris deb + rpm release plan](https://git.bongbetic.com/xavierk/Fenris/issues/33). This document is normative for the follow-up **execution effort** that builds and publishes packages; no packages are built here.
+
+**Canonical roles.** [ADR 0007](../adr/0007-package-delivery-amends-0004.md) records the lifecycle rationale (amending [ADR 0004](../adr/0004-install-upgrade-removal-lifecycle.md)); this document restates the **operative contracts** — compat matrix, channel, toolchain, signing, release mechanics, package layout, maintainer-script behavior, migration — so the executing effort never needs Wayfinder-ticket access. Runtime semantics come from [ADRs 0001–0006](../adr/) and the [redesign specification](fenris-redesign.md) verbatim; nothing here overrides them. Terminology follows the glossary in [`CONTEXT.md`](../../CONTEXT.md), including *Release* and *Rollback*.
+
+**Binding language.** *Must*, *exactly*, and *never* are normative.
+
+## 1. Compatibility matrix
+
+| Target | Version | Format | Registry placement |
+|---|---|---|---|
+| Debian 12 (bookworm) | — | deb | `debian/pool/bookworm/main` |
+| Ubuntu 22.04 (jammy) | — | deb | `debian/pool/jammy/main` |
+| Ubuntu 24.04 (noble) | — | deb | `debian/pool/noble/main` |
+| Fedora 40+ | every release | rpm | `rpm/fenris` group |
+| openSUSE Tumbleweed | rolling | rpm | `rpm/fenris` group |
+
+- Architecture: **x86_64 only** (arm64 only if real ARM hardware appears — map fog).
+- Dependencies are vendored as locked, pure-Python runtime packages for every target: Debian 12 and Ubuntu 22.04/24.04 ship `python3-textual` 0.1.13, far below the floor; Fedora 40+ ships ≥ 0.48 but below the pin ([toolchain research](../research/deb-rpm-toolchain.md)). No distro `python3-textual` dependency ever enters package metadata.
+- Package metadata `depends:`/`Requires:` are exactly `python3 (>= 3.10)`, `smartmontools`, `systemd` — the Python floor is 3.10 (oldest supported distro interpreter, Ubuntu 22.04), bumping ADR 0004 §10's 3.9 gate for packages; `make install` keeps the checkout's floor.
+- Runtime packages are staged with `python3 -m pip --target /opt/fenris/vendor`; entry points run the target system's `python3` with that directory on the import path. No package ships a copied Python interpreter, avoiding build-host ABI paths and rolling-distribution minor-version breakage.
+
+## 2. Distribution channel
+
+- **Channel:** the self-hosted Gitea 1.27.1 package registry at `git.bongbetic.com`, owner public for anonymous consumers ([registry research](../research/gitea-package-registry.md); [OBS rejected](../research/obs-route.md)).
+- **Single channel.** No stable/testing split — deferred until external users ask to track pre-release builds (map fog). Every published version is retained indefinitely (registry has no REST cleanup; republishing a filename is a 409).
+- **deb publication:** one deb artifact PUT to each codename pool — `PUT /api/packages/{owner}/debian/pool/{bookworm|jammy|noble}/main/upload`.
+- **rpm publication:** one rpm artifact PUT to the single `fenris` group — `PUT /api/packages/{owner}/rpm/fenris/upload` — serving Fedora 40+ collectively.
+- **Consumer setup (install docs, normative):**
+  - apt: keyring file from `…/debian/repository.key` via `signed-by`, one sources line per distribution, instance Debian Registry Key **fingerprint printed beside the curl one-liner** (TOFU hardening).
+  - dnf: `dnf config-manager --add-repo <raw-url of packaging/fenris.repo>` — the in-repo, Fenris-owned `.repo` with `gpgkey` pointing at the published packaging key and `repo_gpgcheck=0`. **Gitea's auto-generated `.repo` is never mentioned in docs**: it sets `gpgcheck=1` against the instance auto-key, which never signed our rpm payload — a trap that breaks installs.
+
+## 3. Build toolchain
+
+- **nfpm** for both formats from a single `packaging/nfpm.yaml` — one config, `overrides:` for per-format deltas, two invocations (`nfpm pkg -p deb`, `nfpm pkg -p rpm`). fpm is dropped entirely (CLI-flag config drifts); no hand rpm spec; dh-virtualenv is deb-only and dormant since 2020.
+- **Single source of truth:** version injected from `pyproject.toml`; file lists generated by a staging script (locked runtime packages → `/opt/fenris/vendor`, plus wrapper, helpers, units, polkit policy, sysusers/tmpfiles fragments) referenced by `nfpm.yaml` as a `type: tree` content entry — no hand-maintained file lists.
+- **Entry point:** `make package` → `dist/fenris_<v>_amd64.deb` + `dist/fenris-<v>-1.x86_64.rpm`.
+- **Version scheme:** `<pyproject-version>-1` in both formats; a rebuild of the same upstream version bumps the revision (`-2`, `-3`, …) — the same filename is never re-PUT (registry 409s duplicates).
+- **Authoring `nfpm.yaml`, the staging script, and the workflow file is execution** — deliberately not part of the decision map. The [toolchain research doc](../research/deb-rpm-toolchain.md) sketches the pipeline.
+
+## 4. Signing and key policy
+
+- **RPM payload: signed.** rpmsign with the dedicated packaging key, invoked by `make sign-rpm` after the package is built. This is required, not optional: it is the only working dnf-native verification path.
+- **deb: unsigned.** apt never verifies payload signatures; trust = instance-signed `InRelease` (signed-by keyring) + TLS + Acquire-By-Hash. Manual-download integrity is covered by SHA256SUMS.
+- **SHA256SUMS: clearsigned** with the packaging key — the trust anchor for manually downloaded release assets, independent of TLS.
+- **Packaging key:** single dedicated key, RSA 3072, UID `Fenris Packaging <packaging@bongbetic.com>`, 2-year expiry, no master/subkey hierarchy (single maintainer, manual builds). Private key lives in the password manager only; each release does import → sign → delete — nothing permanent on any build host. The full ceremony is documented in `docs/install/signing-key-ceremony.md`.
+- **Public key publication:** in-repo `packaging/keys/fenris-packaging.asc` (raw URL doubles as the `.repo` gpgkey target), release notes, docs page. No keyservers — TOFU-over-TLS.
+- **Rotation (outline):** new key published alongside old; rpm signed with the new key; `fenris.repo` gpgkey lists both URLs (dnf accepts multiple); old key dropped after one release cycle. Procedure details stay in map fog.
+
+## 5. Release mechanics
+
+- **A Release is:** a version tag, its packages in the channel, a Gitea release entry with notes, and a clearsigned SHA256SUMS — all together. **Bare tags are forbidden** (tag without packages + release entry is not a Release).
+- **Cadence: on-demand.** Tag when user-visible changes or fixes accumulate; no calendar, no empty releases, no frequency SLA, no RC ceremony — fixes ship as a revision bump of the current version.
+- **Versioning: plain semver.** Major = breaking CLI/config/unit change; store schema changes ride the natural bump (the forward-only refusal handles old-reader/new-store).
+- **Promotion flow:** tag → `make release` (automated: `make package` → RPM signing via nfpm → SHA256SUMS generation → clearsign → prints registry PUTs + Gitea release steps). The ceremony is documented in `docs/install/signing-key-ceremony.md`.
+- **Rollback:** installing an older package over a newer store is **unsupported** — the store's forward-only version refusal fails it by design. Documented rollback = restore the observation-store snapshot, then install the old Release. No automatic downgrade machinery exists or will be built.
+- **CI:** no runners are registered on the instance today ([Actions runner research](https://git.bongbetic.com/xavierk/Fenris/issues/37)), so the manual flow above is primary. A dormant `.gitea/workflows/release.yml` (`on: push: tags: ['v*']`, single job, host-mode runner) is committed alongside; if it fires, it replicates `make release`. Cheapest future upgrade: one `act_runner` static binary in host-label mode on the existing Gitea host.
+
+## 6. Package layout and ownership
+
+Per [ADR 0007](../adr/0007-package-delivery-amends-0004.md) §2 — the dpkg/rpm database is the manifest; no `manifest.txt` ships:
+
+| Artifact | Location | Ownership |
+|---|---|---|
+| Bundled runtime packages | `/opt/fenris/vendor` | package (tree) |
+| Wrapper | `/usr/bin/fenris` | package |
+| Helpers | `/usr/libexec/fenris/{fenris-monitor,fenris-collect}` | package — exactly these two, no new polkit-reachable binaries |
+| Units | `/usr/lib/systemd/system/fenris-collect.{timer,service}` | package (vendor placement; `/etc/systemd/system` is admin-only) |
+| Polkit policy | `/usr/share/polkit-1/actions/com.bongbetic.fenris.monitor.policy` | package |
+| sysusers fragment | `/usr/lib/sysusers.d/fenris.conf` (`g fenris -`) | package |
+| tmpfiles fragment | `/usr/lib/tmpfiles.d/fenris.conf` (`d /var/lib/fenris 2750 root fenris -`) | package |
+| Configuration | `/etc/fenris/fenris.conf` | package as conffile / `%config(noreplace)` — placeholder-commented default, no active selector |
+| Observation store | `/var/lib/fenris/observations.db` (+ WAL, `.bak`) | **never owned, never ghosted** — the package owns the directory only |
+
+## 7. Maintainer-script contracts
+
+- **preinst / %pre:** abort with a pointer to the migration runbook (§9) if `/var/lib/fenris/manifest.txt` **or** `/etc/systemd/system/fenris-collect.timer` exists (dual marker covers pre-manifest make installs). No auto-clean — scripts never delete files outside the package DB.
+- **postinst / %post (install):** `systemd-sysusers`, `systemd-tmpfiles --create`, `systemctl daemon-reload`. Nothing else — no enable, no preset, no start; no preset file ships.
+- **postinst / %post (upgrade):** snapshot `observations.db` → `.bak` (one generation) → forward-only schema migration via target `python3` with `/opt/fenris/vendor` on its import path → `daemon-reload` → restart `fenris-collect.timer` only if unit contents changed **and** it is active. `/var/lib/fenris` is never rebuilt; an in-flight oneshot finishes on its old interpreter.
+- **prerm / %preun:** sanctioned disable (`fenris-monitor disable --now`, closing the monitoring period `user_disabled`) on remove/erase **only, never on upgrade** — deb prerm upgrade case is a no-op; rpm `%preun` gated on `$1 -eq 0`.
+- **Removal mapping:** deb `remove` ≈ `make uninstall` (conffile + store survive); deb `purge` ≈ `make purge` (+ `.bak`, group cleanup); rpm erase ≈ `make uninstall` (unmodified config removed, modified survives as `.rpmsave`); rpm purge = documented manual command.
+
+## 8. Initial configuration
+
+- The device selector is **entered by hand**: root edits `/etc/fenris/fenris.conf` (world-readable, exactly one key per [ADR 0003](../adr/0003-service-lifecycle-and-sanctioned-toggle.md) §3). The shipped default is placeholder-commented and carries no active selector — a fresh install reads as a `configuration error`-free dormant system until the first `fenris monitor resume` + edit, exactly the dormant-install contract.
+- No configuration verb is added to `fenris-monitor`; the polkit surface stays at one binary. (This resolves the open item from [Package ownership + ADR 0004 amendment](https://git.bongbetic.com/xavierk/Fenris/issues/40): nothing in any delivery writes the selector — `make install` never wrote `fenris.conf` either; hand-editing has been the model since ADR 0003.)
+- On upgrade, local edits survive; a changed package default lands as `.dpkg-new` / `.rpmnew`.
+
+## 9. Migration from make-install systems
+
+- **Runbook only** — no migration script, no auto-clean. Population is author machines plus a few testers; store and config survive by path continuity.
+- **Remove-then-install, mandatory:** `sudo make uninstall` (preserves store + `/etc/fenris`) → `apt install fenris` / `dnf install fenris`. **Over-install is forbidden:** stale `/etc/systemd/system/fenris-collect.*` silently shadows vendor units (systemd precedence), `/usr/local/bin/fenris` shadows `/usr/bin/fenris` on PATH.
+- **No-move continuity:** `/var/lib/fenris` untouched; existing `fenris` group → sysusers no-op; existing dir → tmpfiles no-op; hand-written `fenris.conf` survives (dpkg ships the default as `.dpkg-new`; rpm as `.rpmnew`); store schema caught up by the upgrade-path migration.
+- **Reset-to-dormant:** `make uninstall`'s sanctioned disable closes the open period `user_disabled`; after migration the user opts back in with `fenris monitor resume` — one ≤15-min sample gap, honest against the endurance timeline.
+- **Mutual exclusion:** package and `make install` never on the same machine. The dev loop is checkout + `make test`; a dev-local install mode stays in map fog.
+
+## 10. Out of scope
+
+- Building and publishing packages (the follow-up execution effort).
+- Snap/Flatpak/AppImage/Homebrew, PyPI as an install path.
+- Stable/testing channel split, COPR/PPA fallback, arm64 — map fog until demand appears.
+
+---
+
+*Assembled from [Lock channel + toolchain](https://git.bongbetic.com/xavierk/Fenris/issues/38), [Signing + key policy](https://git.bongbetic.com/xavierk/Fenris/issues/39), [Package ownership + ADR 0004 amendment](https://git.bongbetic.com/xavierk/Fenris/issues/40), [Migration path from make-install systems to packages](https://git.bongbetic.com/xavierk/Fenris/issues/41), [Release cadence + stable/testing channel split](https://git.bongbetic.com/xavierk/Fenris/issues/43), [Actions runner availability](https://git.bongbetic.com/xavierk/Fenris/issues/37), and the research tickets [deb + rpm packaging toolchain](https://git.bongbetic.com/xavierk/Fenris/issues/34), [Gitea 1.27 package registry feasibility](https://git.bongbetic.com/xavierk/Fenris/issues/35), [OBS route](https://git.bongbetic.com/xavierk/Fenris/issues/36).*

docs/spec/xbps-proof-results.md

@@ -0,0 +1,153 @@
+# XBPS Proof of Concept Results (Issue #83)
+
+Status: Complete. All acceptance criteria satisfied.
+
+## Summary
+
+Signed XBPS installation and immediate updates through Gitea have been demonstrated
+and verified end-to-end. The publication mechanism is repeatable and documented for
+subsequent tickets.
+
+## Acceptance Criteria Results
+
+### 1. Permanent raw URL delivery without LFS indirection
+
+**Result: PASS**
+
+All artifacts are served directly by Gitea via raw-file URLs:
+
+- Repository: `https://git.bongbetic.com/xavierk/Fenris-xbps`
+- Raw URL pattern: `https://git.bongbetic.com/xavierk/Fenris-xbps/raw/branch/stable/x86_64/<file>`
+
+Verified files:
+- `x86_64-repodata` (1327 bytes) — HTTP 200
+- `fenris-0.3.5_1.x86_64.xbps` (731 bytes) — HTTP 200
+- `fenris-0.3.5_1.x86_64.xbps.sig2` (384 bytes) — HTTP 200
+- `fenris-0.3.6_1.x86_64.xbps` (752 bytes) — HTTP 200
+- `fenris-0.3.6_1.x86_64.xbps.sig2` (384 bytes) — HTTP 200
+
+No LFS indirection detected. Files served as ordinary Git blobs.
+
+### 2. Signing-key handling and trust verification
+
+**Result: PASS**
+
+Signing uses SSH RSA keys (3072-bit) via `xbps-rindex --sign-pkg` and `xbps-rindex --sign`.
+The public key is embedded in the repository metadata (`index-meta.plist`) within the
+repodata archive. XBPS clients prompt for key import on first access and verify
+signatures automatically.
+
+Key characteristics:
+- Private key: SSH RSA format, stored externally (not in repository)
+- Public key: Embedded in repodata, base64-encoded PKCS#8 format
+- Package signatures: `.sig2` files alongside each `.xbps` archive
+- Repository signature: Embedded in `x86_64-repodata` metadata
+
+### 3. Install and update with client that fetched old index
+
+**Result: PASS**
+
+Demonstrated full lifecycle:
+
+1. Fresh install of v0.3.5 from repository with only v0.3.5 in index
+2. Added v0.3.6 to index and committed to `stable` branch
+3. Client performed `xbps-install -Syu` and upgraded from 0.3.5 → 0.3.6
+
+The upgrade was detected and executed without manual intervention:
+```
+fenris (0.3.5_1 -> 0.3.6_1)
+```
+
+### 4. Cache behavior and binary size limits
+
+**Result: PASS (with documented caveat)**
+
+Cache behavior:
+- Gitea raw endpoint: `cache-control: public, max-age=21600` (6-hour cache)
+- ETag changes on each commit (different file hash)
+- Conditional requests with old ETag return 200 (full content), not 304
+
+xbps-install behavior:
+- Always fetches fresh repodata with `-S` flag
+- Respects ETag changes for immediate discovery
+- No 6-hour delay observed in practice
+
+Binary size limits:
+- Test packages: 731–752 bytes (small test artifacts)
+- Real packages expected to be <10MB (vendored pure-Python)
+- Gitea serves any file size without LFS
+
+**Caveat**: Clients using `xbps-install -Su` without `-S` may use cached repodata.
+The `-S` flag forces a fresh fetch. Users should always use `-Syu` for updates.
+
+### 5. Publish index/artifacts together, preserve older artifacts, safe failure recovery
+
+**Result: PASS**
+
+Publication mechanism:
+- Index and new package committed together in single Git commit
+- Older package artifacts retained in tree (e.g., v0.3.5 alongside v0.3.6)
+- Clients with cached older indexes can still download older packages
+
+Failure recovery:
+- Demonstrated with simulated corruption (corrupted repodata committed)
+- Recovery via `git revert` restored correct state
+- Previous state accessible via Git history at all times
+
+### 6. Record results and publication mechanism
+
+**Result: PASS**
+
+Publication script created: `scripts/xbps-publish.sh`
+- Automates: build → sign → clone repo → update index → commit → push
+- Supports `--dry-run` and `--publish` modes
+- Follows same pattern as existing `scripts/release.sh`
+
+Makefile targets added:
+- `package-xbps` — Build XBPS package
+- `sign-xbps` — Sign XBPS package
+- `xbps-publish` — Publish to distribution repository
+- `xbps-publish-dry-run` — Dry-run publication
+
+## Repository Structure
+
+```
+xavierk/Fenris-xbps (stable branch)
+  x86_64/
+    fenris-<version>_1.x86_64.xbps       # Package archives
+    fenris-<version>_1.x86_64.xbps.sig2   # Package signatures
+    x86_64-repodata                        # Repository index (zstd-compressed tar)
+    x86_64-repodata.sig2                   # Repository metadata signature
+  keys/
+    fenris-xbps-signing.pub                # Public signing key
+  README.md
+```
+
+## Client Configuration
+
+Users add the repository to `/etc/xbps.d/xbps.conf`:
+```
+repository=https://git.bongbetic.com/xavierk/Fenris-xbps/raw/branch/stable/x86_64
+```
+
+Or install directly:
+```sh
+sudo xbps-install -S https://git.bongbetic.com/xavierk/Fenris-xbps/raw/branch/stable/x86_64
+```
+
+## Publication Mechanism
+
+1. Build: `make package-xbps`
+2. Sign: `make sign-xbps` (or `scripts/xbps-publish.sh` handles this)
+3. Publish: `make xbps-publish`
+4. Verify: Check raw URL returns HTTP 200
+
+The publication script (`scripts/xbps-publish.sh`) automates the full flow:
+build → sign → clone repo → add to index → sign repository → commit → push.
+
+## Dependencies for Subsequent Tickets
+
+- **Issue #86** (Publish validated package formats): Uses this publication mechanism
+  for real Fenris packages instead of test artifacts.
+- **Issue #87** (Validate on Void machine): Uses the established repository URL
+  and signing infrastructure for end-to-end validation.

fenris.sh

@@ -1,128 +0,0 @@
-#!/usr/bin/env bash
-# Fenris — interactive menu for the NVMe wear monitor & dashboard.
-# Created by Bongbetic.
-
-set -euo pipefail
-SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
-PY="$SCRIPT_DIR/fenris.py"
-PORT_DEFAULT=8420
-INTERVAL_DEFAULT=300
-
-banner() {
-  cat <<'EOF'
- _____           _
-|   __|___ ___ _| |___
-|   __| -_|   | . |  _|
-|__|  |___|_|_|_|___|_|
-
- NVMe wear monitor & live dashboard
- Created by Bongbetic
-EOF
-}
-
-pause() { read -rp "Press Enter to continue..." _; }
-
-detect_device() {
-  # Query Python's auto-detect for the default device.
-  python3 -c "import sys; sys.path.insert(0,'$SCRIPT_DIR'); from fenris import detect_device; print(detect_device())" 2>/dev/null || echo /dev/nvme0
-}
-
-menu() {
-  clear
-  banner
-  echo
-  echo "  1) Start monitoring (background daemon + dashboard)"
-  echo "  2) Stop monitoring"
-  echo "  3) Status / current wear stats"
-  echo "  4) Take one sample right now"
-  echo "  5) Open dashboard URL"
-  echo "  ---"
-  echo "  h) Help / how this works"
-  echo "  q) Exit"
-  echo
-  read -rp "Choose an option: " choice
-  echo
-  case "$choice" in
-    1) start_flow ;;
-    2) python3 "$PY" stop; pause ;;
-    3) python3 "$PY" status; pause ;;
-    4) read -rp "Device [default: auto-detect]: " dev
-       if [ -z "$dev" ]; then python3 "$PY" sample; else python3 "$PY" sample --device "$dev"; fi
-       pause ;;
-    5) show_url; pause ;;
-    h|H) help_text; pause ;;
-    q|Q) echo "Bye. — Fenris, by Bongbetic"; exit 0 ;;
-    *) echo "Invalid choice."; pause ;;
-  esac
-}
-
-start_flow() {
-  read -rp "NVMe device [Enter = auto-detect]: " dev
-  read -rp "Sample interval in seconds [Enter = ${INTERVAL_DEFAULT}]: " interval
-  read -rp "Dashboard port [Enter = ${PORT_DEFAULT}]: " port
-  interval="${interval:-$INTERVAL_DEFAULT}"
-  port="${port:-$PORT_DEFAULT}"
-
-  args=(start --interval "$interval" --port "$port")
-  if [ -n "${dev:-}" ]; then args+=(--device "$dev"); fi
-
-  echo
-  echo "Note: reading NVMe SMART data needs root."
-  echo "Fenris runs 'sudo -n smartctl ...' (no-prompt sudo). If this fails,"
-  echo "either run this menu with sudo, or allow passwordless smartctl via:"
-  echo "  sudo visudo   ->   youruser ALL=(root) NOPASSWD: /usr/sbin/smartctl"
-  echo
-
-  python3 "$PY" "${args[@]}"
-  pause
-}
-
-show_url() {
-  if [ -f "$SCRIPT_DIR/data/fenris.pid" ]; then
-    # Try to read actual port from running process cmdline, else guess default.
-    local pid port
-    pid=$(<"$SCRIPT_DIR/data/fenris.pid")
-    port=$(tr '\0' '\n' < /proc/"$pid"/cmdline 2>/dev/null | grep -A1 -- '--port' | tail -1 || true)
-    port="${port:-$PORT_DEFAULT}"
-    echo "Dashboard: http://localhost:${port}"
-  else
-    echo "Fenris is not currently running. Start it first (option 1)."
-  fi
-}
-
-help_text() {
-  cat <<EOF
-What Fenris does:
-  - Periodically reads your NVMe drive's SMART health data (via smartctl),
-    including "percentage_used" (the drive's own wear indicator), total
-    bytes written/read, temperature, spare capacity, and error counts.
-  - Logs every sample to: $SCRIPT_DIR/data/history.jsonl
-    and per-hour aggregates to: $SCRIPT_DIR/data/hourly.jsonl (GB/hour,
-    rebuilt from history on restart). Used for the trailing-24h bar chart
-    and exact rolling-24h write volume.
-  - Serves a live HTML dashboard (dense layout, interval-synced polling)
-    with wear-over-time and trailing-24h hourly-write charts, plus a
-    projected life-remaining estimate in hours/days/years derived from
-    your actual rolling-24h write rate and implied TBW endurance.
-
-Requirements:
-  - smartmontools (smartctl) installed.
-  - Root access to read NVMe SMART logs — either run Fenris via sudo,
-    or set up passwordless sudo for smartctl (see option 1).
-
-CLI usage (equivalent to this menu):
-  python3 fenris.py start    [--device /dev/nvme0] [--interval 300] [--port 8420]
-  python3 fenris.py stop
-  python3 fenris.py status
-  python3 fenris.py sample   [--device /dev/nvme0]
-
-Leave it running in the background (option 1) and check back after a
-few days/weeks of normal use — more samples = a more accurate lifespan
-estimate.
-
-Fenris — created by Bongbetic.
-EOF
-}
-
-# Loop instead of recurse to avoid stack overflow.
-while true; do menu; done

packaging/fenris.conf

@@ -0,0 +1,16 @@
+# Fenris configuration
+#
+# This file is managed by the fenris package. Local edits are preserved
+# across upgrades; changed defaults appear as .dpkg-new / .rpmnew.
+#
+# The device selector specifies which NVMe drive to monitor.
+# Uncomment and set exactly one device path:
+#
+#   device = /dev/disk/by-id/nvme-Samsung_SSD_980_PRO_500GB_S5PANS0T123456
+#
+# The observation store path is optional and defaults to
+# /var/lib/fenris/observations.db when unset:
+#
+#   store_path = /var/lib/fenris/observations.db
+#
+# See https://git.bongbetic.com/xavierk/Fenris for documentation.

packaging/fenris.repo

@@ -0,0 +1,7 @@
+[fenris]
+name=Fenris NVMe Monitor
+baseurl=https://git.bongbetic.com/api/packages/xavierk/rpm/fenris
+enabled=1
+gpgcheck=1
+gpgkey=https://git.bongbetic.com/xavierk/Fenris/raw/branch/main/packaging/keys/fenris-packaging.asc
+repo_gpgcheck=0

packaging/keys/fenris-packaging.asc

@@ -0,0 +1,40 @@
+# Fenris Packaging Key
+#
+# Public half of dedicated RSA-3072 key used to sign RPM payloads and
+# clearsign SHA256SUMS manifests.
+#
+# Fingerprint: CE4542E1E23EB50F09EDFFA5A5E8B22D1872FB07
+# Algorithm: RSA 3072
+# UID: Fenris Packaging <packaging@bongbetic.com>
+# Expiry: 2 years from creation
+#
+# Raw URL:
+#   https://git.bongbetic.com/xavierk/Fenris/raw/branch/main/packaging/keys/fenris-packaging.asc
+#
+# The private half lives in approved secret storage only. Each release uses
+# import -> sign -> delete. See docs/install/signing-key-ceremony.md.
+#
+-----BEGIN PGP PUBLIC KEY BLOCK-----
+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+=V4/R
+-----END PGP PUBLIC KEY BLOCK-----

packaging/nfpm.yaml

@@ -0,0 +1,60 @@
+name: fenris
+arch: amd64
+platform: linux
+version: "${VERSION}"
+maintainer: Fenris Maintainers <ops@bongbetic.com>
+description: >
+  NVMe wear monitor with persistent TUI — observes real-world drive use and
+  translates it into an understandable endurance outlook.
+homepage: https://git.bongbetic.com/xavierk/Fenris
+license: Proprietary
+
+depends:
+  - python3 (>= 3.10)
+  - smartmontools
+  - systemd
+
+contents:
+  # Staged tree: runtime packages, wrapper, helpers, units, polkit, sysusers, tmpfiles
+  - src: build/stage/
+    dst: /
+    type: tree
+
+  # Configuration directory
+  - dst: /etc/fenris
+    type: dir
+    file_info:
+      mode: 0755
+
+  # Default placeholder-commented config (deb conffile / rpm %config(noreplace))
+  - src: packaging/fenris.conf
+    dst: /etc/fenris/fenris.conf
+    type: config|noreplace
+    file_info:
+      mode: 0644
+
+  # Observation store directory — owned by package, never packed.
+  # Store files (observations.db, WAL sidecars, .bak) are never owned.
+  - dst: /var/lib/fenris
+    type: dir
+    file_info:
+      mode: 2750
+      group: fenris
+
+scripts:
+  preinstall: packaging/preinst.sh
+  postinstall: packaging/postinst.sh
+  preremove: packaging/prerm.sh
+  postremove: packaging/postrm.sh
+
+overrides:
+  rpm:
+    depends:
+      - python3 >= 3.10
+      - smartmontools
+      - systemd
+    scripts:
+      preinstall: packaging/preinst.sh
+      postinstall: packaging/rpm/post.sh
+      preremove: packaging/rpm/preun.sh
+      postremove: packaging/rpm/postun.sh

packaging/postinst.sh

@@ -0,0 +1,78 @@
+#!/bin/sh
+# postinst — deb install and upgrade paths (spec §7).
+#
+# dpkg calls: postinst configure [most-recently-configured-version]
+#   fresh install: $1 = "configure", $2 = ""
+#   upgrade:       $1 = "configure", $2 = old version
+set -eu
+
+STORE_DIR="/var/lib/fenris"
+STORE_DB="${STORE_DIR}/observations.db"
+STORE_BAK="${STORE_DIR}/observations.db.bak"
+RUNTIME_PYTHON="/usr/bin/python3"
+VENDOR_DIR="/opt/fenris/vendor"
+
+# Detect init system
+if [ -d /run/systemd/system ] || [ "$(cat /proc/1/comm 2>/dev/null)" = "systemd" ]; then
+    INIT_SYSTEM="systemd"
+else
+    INIT_SYSTEM="runit"
+fi
+
+case "${1:-}" in
+    configure)
+        if [ -n "${2:-}" ]; then
+            # Upgrade — snapshot, migration, init-system-aware reload
+            if [ -f "${STORE_DB}" ]; then
+                cp "${STORE_DB}" "${STORE_BAK}" 2>/dev/null || true
+            fi
+            if [ -d "${VENDOR_DIR}" ] && [ -f "${STORE_DB}" ]; then
+                PYTHONPATH="${VENDOR_DIR}" "${RUNTIME_PYTHON}" -c "
+from fenris.store import migrate_to_latest
+from pathlib import Path
+n = migrate_to_latest(Path('${STORE_DB}'))
+print(f'Fenris migration: {n} step(s) applied') if n else None
+" 2>&1 || echo "Fenris: migration skipped (store not yet initialized)"
+            fi
+            if [ "${INIT_SYSTEM}" = "systemd" ]; then
+                # Capture running unit content BEFORE daemon-reload (spec §7)
+                RUNNING_UNITS=""
+                for unit in fenris-collect.timer; do
+                    if systemctl is-active --quiet "${unit}" 2>/dev/null; then
+                        RUNNING_UNITS="${RUNNING_UNITS} ${unit}"
+                    fi
+                done
+                systemctl daemon-reload 2>/dev/null || true
+                # Restart timer only if unit contents changed AND active
+                for unit in ${RUNNING_UNITS}; do
+                    OLD_CONTENT="$(mktemp)"
+                    NEW_PATH="/usr/lib/systemd/system/${unit}"
+                    systemctl cat "${unit}" > "${OLD_CONTENT}" 2>/dev/null || true
+                    if ! diff -q "${OLD_CONTENT}" "${NEW_PATH}" > /dev/null 2>&1; then
+                        systemctl restart "${unit}" 2>/dev/null || true
+                    fi
+                    rm -f "${OLD_CONTENT}"
+                done
+            fi
+        fi
+        # Fresh install: init-system-specific setup
+        if [ "${INIT_SYSTEM}" = "systemd" ]; then
+            systemd-sysusers  || true
+            systemd-tmpfiles --create  || true
+            systemctl daemon-reload  || true
+        else
+            # runit: create group, set directory permissions
+            groupadd -f fenris
+            install -d -o root -g fenris -m 2750 "${STORE_DIR}" 2>/dev/null || true
+            # Mark runit service as dormant (down) for fresh install
+            if [ -d /etc/sv/fenris-collect ] && [ ! -e /var/service/fenris-collect ]; then
+                touch /etc/sv/fenris-collect/down
+            fi
+            # Ensure log directory exists
+            mkdir -p /var/log/fenris-collect
+            chown fenris:fenris /var/log/fenris-collect 2>/dev/null || true
+        fi
+        ;;
+    abort-upgrade|abort-install|disappear)
+        ;;
+esac

packaging/postrm.sh

@@ -0,0 +1,32 @@
+#!/bin/sh
+# postrm — deb post-removal (spec §7, §9).
+#
+# dpkg calls: postrm remove    (after package files removed)
+#             postrm purge     (after conffiles and config removed)
+set -eu
+
+# Detect init system
+if [ -d /run/systemd/system ] || [ "$(cat /proc/1/comm 2>/dev/null)" = "systemd" ]; then
+    INIT_SYSTEM="systemd"
+else
+    INIT_SYSTEM="runit"
+fi
+
+case "${1:-}" in
+    purge)
+        rm -rf /etc/fenris
+        rm -rf /var/lib/fenris
+        if getent group fenris > /dev/null 2>&1; then
+            groupdel fenris 2>/dev/null || true
+        fi
+        ;;
+    remove|upgrade|failed-upgrade|abort-install|abort-upgrade|disappear)
+        ;;
+esac
+if [ "${INIT_SYSTEM}" = "systemd" ]; then
+    systemctl daemon-reload 2>/dev/null || true
+else
+    # runit: clean up service directory and log
+    rm -rf /etc/sv/fenris-collect 2>/dev/null || true
+    rm -rf /var/log/fenris-collect 2>/dev/null || true
+fi

packaging/preinst.sh

@@ -0,0 +1,19 @@
+#!/bin/sh
+# preinst — abort if make-install remnants detected (spec §7, §9).
+set -eu
+
+MARKER1="/var/lib/fenris/manifest.txt"
+MARKER2="/etc/systemd/system/fenris-collect.timer"
+
+if [ -f "${MARKER1}" ] || [ -f "${MARKER2}" ]; then
+    echo >&2
+    echo >&2 "Fenris make-install remnants detected — refusing to install."
+    echo >&2
+    echo >&2 "Migrate to the package with:"
+    echo >&2 "  sudo make uninstall   # removes make-install files, preserves store + config"
+    echo >&2 "  sudo apt install fenris   # or: sudo dnf install fenris"
+    echo >&2
+    echo >&2 "See: https://git.bongbetic.com/xavierk/Fenris/blob/main/docs/spec/release-packaging.md#9-migration-from-make-install-systems"
+    echo >&2
+    exit 1
+fi

packaging/prerm.sh

@@ -0,0 +1,33 @@
+#!/bin/sh
+# prerm — deb pre-removal (spec §7).
+#
+# dpkg calls: prerm remove  (package being removed)
+#             prerm upgrade  (old version about to be replaced)
+set -eu
+
+# Detect init system
+if [ -d /run/systemd/system ] || [ "$(cat /proc/1/comm 2>/dev/null)" = "systemd" ]; then
+    INIT_SYSTEM="systemd"
+else
+    INIT_SYSTEM="runit"
+fi
+
+case "${1:-}" in
+    remove)
+        # Sanctioned disable — close monitoring period (spec §7)
+        if [ -x /usr/libexec/fenris/fenris-monitor ]; then
+            /usr/libexec/fenris/fenris-monitor disable --now 2>/dev/null || true
+        fi
+        if [ "${INIT_SYSTEM}" = "systemd" ]; then
+            systemctl stop fenris-collect.timer 2>/dev/null || true
+            systemctl disable fenris-collect.timer 2>/dev/null || true
+        else
+            # runit: remove the service symlink
+            rm -f /var/service/fenris-collect
+            touch /etc/sv/fenris-collect/down 2>/dev/null || true
+        fi
+        ;;
+    upgrade)
+        # Never interrupt monitoring on upgrade
+        ;;
+esac

packaging/release-footer.md

@@ -0,0 +1,20 @@
+## Install
+
+Install Fenris from its package channel after following the [package setup instructions](https://git.bongbetic.com/xavierk/Fenris/src/branch/main/README.md#install-from-package-recommended):
+
+```bash
+sudo apt update && sudo apt install fenris       # Debian / Ubuntu
+sudo dnf install fenris                          # Fedora
+sudo zypper install fenris                       # openSUSE Tumbleweed
+```
+
+## Verify downloads
+
+```bash
+gpg --output SHA256SUMS --decrypt SHA256SUMS.asc
+sha256sum -c SHA256SUMS
+```
+
+## Rollback
+
+Installing an older package over a newer observation store is unsupported. Restore the observation-store snapshot, then install the earlier Release; see the [upgrade and rollback guidance](https://git.bongbetic.com/xavierk/Fenris/src/branch/main/README.md#upgrade).

packaging/rpm/post.sh

@@ -0,0 +1,71 @@
+#!/bin/sh
+# RPM %post — post-install/upgrade scriptlet (spec §7).
+set -eu
+
+STORE_DIR="/var/lib/fenris"
+STORE_DB="${STORE_DIR}/observations.db"
+STORE_BAK="${STORE_DIR}/observations.db.bak"
+RUNTIME_PYTHON="/usr/bin/python3"
+VENDOR_DIR="/opt/fenris/vendor"
+
+# Detect init system
+if [ -d /run/systemd/system ] || [ "$(cat /proc/1/comm 2>/dev/null)" = "systemd" ]; then
+    INIT_SYSTEM="systemd"
+else
+    INIT_SYSTEM="runit"
+fi
+
+if [ "$1" -eq 1 ]; then
+    # Fresh install
+    if [ "${INIT_SYSTEM}" = "systemd" ]; then
+        systemd-sysusers  || true
+        systemd-tmpfiles --create  || true
+        systemctl daemon-reload  || true
+    else
+        # runit: create group, set directory permissions
+        groupadd -f fenris
+        install -d -o root -g fenris -m 2750 "${STORE_DIR}" 2>/dev/null || true
+        # Mark runit service as dormant (down) for fresh install
+        if [ -d /etc/sv/fenris-collect ] && [ ! -e /var/service/fenris-collect ]; then
+            touch /etc/sv/fenris-collect/down
+        fi
+        # Ensure log directory exists
+        mkdir -p /var/log/fenris-collect
+        chown fenris:fenris /var/log/fenris-collect 2>/dev/null || true
+    fi
+elif [ "$1" -ge 2 ]; then
+    # Upgrade — snapshot, migration, init-system-aware reload
+    if [ -f "${STORE_DB}" ]; then
+        cp "${STORE_DB}" "${STORE_BAK}" 2>/dev/null || true
+    fi
+    if [ -d "${VENDOR_DIR}" ] && [ -f "${STORE_DB}" ]; then
+        PYTHONPATH="${VENDOR_DIR}" "${RUNTIME_PYTHON}" -c "
+from fenris.store import migrate_to_latest
+from pathlib import Path
+n = migrate_to_latest(Path('${STORE_DB}'))
+print(f'Fenris migration: {n} step(s) applied') if n else None
+" 2>&1 || echo "Fenris: migration skipped (store not yet initialized)"
+    fi
+    if [ "${INIT_SYSTEM}" = "systemd" ]; then
+        # Capture running unit content BEFORE daemon-reload (spec §7)
+        RUNNING_UNITS=""
+        for unit in fenris-collect.timer; do
+            if systemctl is-active --quiet "${unit}" 2>/dev/null; then
+                RUNNING_UNITS="${RUNNING_UNITS} ${unit}"
+            fi
+        done
+        systemctl daemon-reload 2>/dev/null || true
+        # Restart timer only if unit contents changed AND active
+        for unit in ${RUNNING_UNITS}; do
+            OLD_CONTENT="$(mktemp)"
+            NEW_PATH="/usr/lib/systemd/system/${unit}"
+            systemctl cat "${unit}" > "${OLD_CONTENT}" 2>/dev/null || true
+            if ! diff -q "${OLD_CONTENT}" "${NEW_PATH}" > /dev/null 2>&1; then
+                systemctl restart "${unit}" 2>/dev/null || true
+            fi
+            rm -f "${OLD_CONTENT}"
+        done
+        # Re-apply placement modes (store dir group access, issue #54)
+        systemd-tmpfiles --create  || true
+    fi
+fi

packaging/rpm/postun.sh

@@ -0,0 +1,26 @@
+#!/bin/sh
+# RPM %postun — post-uninstall scriptlet (spec §7).
+set -eu
+
+# Detect init system
+if [ -d /run/systemd/system ] || [ "$(cat /proc/1/comm 2>/dev/null)" = "systemd" ]; then
+    INIT_SYSTEM="systemd"
+else
+    INIT_SYSTEM="runit"
+fi
+
+if [ "$1" -eq 0 ]; then
+    # Package fully erased — remove config, store, group
+    rm -rf /etc/fenris
+    rm -rf /var/lib/fenris
+    if getent group fenris > /dev/null 2>&1; then
+        groupdel fenris 2>/dev/null || true
+    fi
+fi
+if [ "${INIT_SYSTEM}" = "systemd" ]; then
+    systemctl daemon-reload 2>/dev/null || true
+else
+    # runit: clean up service directory and log
+    rm -rf /etc/sv/fenris-collect 2>/dev/null || true
+    rm -rf /var/log/fenris-collect 2>/dev/null || true
+fi

packaging/rpm/preun.sh

@@ -0,0 +1,26 @@
+#!/bin/sh
+# RPM %preun — pre-uninstall scriptlet (spec §7).
+set -eu
+
+# Detect init system
+if [ -d /run/systemd/system ] || [ "$(cat /proc/1/comm 2>/dev/null)" = "systemd" ]; then
+    INIT_SYSTEM="systemd"
+else
+    INIT_SYSTEM="runit"
+fi
+
+if [ "$1" -eq 0 ]; then
+    # Package is being erased — sanctioned disable (spec §7)
+    if [ -x /usr/libexec/fenris/fenris-monitor ]; then
+        /usr/libexec/fenris/fenris-monitor disable --now 2>/dev/null || true
+    fi
+    if [ "${INIT_SYSTEM}" = "systemd" ]; then
+        systemctl stop fenris-collect.timer 2>/dev/null || true
+        systemctl disable fenris-collect.timer 2>/dev/null || true
+    else
+        # runit: remove the service symlink
+        rm -f /var/service/fenris-collect
+        touch /etc/sv/fenris-collect/down 2>/dev/null || true
+    fi
+fi
+# On upgrade ($1 -ge 1): do nothing

packaging/stage.sh

@@ -0,0 +1,97 @@
+#!/usr/bin/env bash
+# Stage a packaging tree at build/stage/ for nfpm consumption.
+#
+# Usage: packaging/stage.sh [VERSION]
+#
+# VERSION defaults to the version in pyproject.toml.
+# The staged tree contains:
+#   /opt/fenris/vendor/   — bundled pure-Python application dependencies
+#   /usr/bin/fenris       — unprivileged wrapper
+#   /usr/libexec/fenris/  — fenris-monitor, fenris-collect
+#   /usr/lib/systemd/system/ — fenris-collect.{timer,service}
+#   /usr/share/polkit-1/actions/ — polkit policy
+#   /usr/lib/sysusers.d/fenris.conf
+#   /usr/lib/tmpfiles.d/fenris.conf
+set -euo pipefail
+
+REPO_ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+STAGE_DIR="${REPO_ROOT}/build/stage"
+
+# --- Resolve version ---
+if [ -n "${1:-}" ]; then
+    VERSION="$1"
+else
+    VERSION="$(sed -n 's/^version = "\(.*\)"/\1/p' "${REPO_ROOT}/pyproject.toml")"
+fi
+
+if [ -z "${VERSION}" ]; then
+    echo "Error: could not determine version" >&2
+    exit 1
+fi
+echo "Staging fenris ${VERSION} ..."
+
+# --- Clean previous stage ---
+rm -rf "${STAGE_DIR}"
+mkdir -p "${STAGE_DIR}"
+
+# --- Use pre-built wheel from dist/ ---
+WHEEL=$(ls "${REPO_ROOT}"/dist/fenris-"${VERSION}"-*.whl 2>/dev/null | head -1)
+if [ -z "${WHEEL}" ]; then
+    echo "Error: no wheel found in dist/ — run 'make dist/fenris-*.whl' first" >&2
+    exit 1
+fi
+echo "  Using wheel: $(basename "${WHEEL}")"
+
+# --- Vendor runtime packages without an interpreter ---
+# A copied Python binary contains an ABI and build-host dynamic-library path.
+# It fails after rolling-distribution Python upgrades (for example Tumbleweed
+# 3.12 -> 3.13).  Fenris and its locked dependencies are pure Python, so place
+# them in a version-neutral directory and execute with the target's python3.
+echo "  Installing version-neutral runtime packages ..."
+VENDOR_DIR="${STAGE_DIR}/opt/fenris/vendor"
+mkdir -p "${VENDOR_DIR}"
+python3 -m pip install --disable-pip-version-check --no-compile \
+    --target "${VENDOR_DIR}" -r "${REPO_ROOT}/requirements.txt" "${WHEEL}"
+
+# --- Inject version into wrapper from pyproject.toml ---
+# The wrapper has a hardcoded version string; patch it for packaging.
+WRAPPER_SRC="${REPO_ROOT}/scripts/fenris"
+WRAPPER_DST="${STAGE_DIR}/usr/bin/fenris"
+mkdir -p "$(dirname "${WRAPPER_DST}")"
+sed "s|version=\"%(prog)s [0-9.]*\"|version=\"%(prog)s ${VERSION}\"|g" \
+    "${WRAPPER_SRC}" > "${WRAPPER_DST}"
+chmod 0755 "${WRAPPER_DST}"
+
+# --- Privileged helpers ---
+echo "  Installing helpers ..."
+mkdir -p "${STAGE_DIR}/usr/libexec/fenris"
+install -m 0755 "${REPO_ROOT}/src/fenris/monitor.py" "${STAGE_DIR}/usr/libexec/fenris/fenris-monitor"
+install -m 0755 "${REPO_ROOT}/src/fenris/collect.py" "${STAGE_DIR}/usr/libexec/fenris/fenris-collect"
+
+# --- systemd units (vendor placement) ---
+echo "  Installing systemd units ..."
+mkdir -p "${STAGE_DIR}/usr/lib/systemd/system"
+install -m 0644 "${REPO_ROOT}/units/fenris-collect.timer"   "${STAGE_DIR}/usr/lib/systemd/system/"
+install -m 0644 "${REPO_ROOT}/units/fenris-collect.service" "${STAGE_DIR}/usr/lib/systemd/system/"
+
+# --- runit service files ---
+echo "  Installing runit service files ..."
+mkdir -p "${STAGE_DIR}/etc/sv/fenris-collect/log"
+install -m 0755 "${REPO_ROOT}/units/runit/fenris-collect/run"     "${STAGE_DIR}/etc/sv/fenris-collect/run"
+install -m 0755 "${REPO_ROOT}/units/runit/fenris-collect/log/run" "${STAGE_DIR}/etc/sv/fenris-collect/log/run"
+
+# --- polkit policy ---
+echo "  Installing polkit policy ..."
+mkdir -p "${STAGE_DIR}/usr/share/polkit-1/actions"
+install -m 0644 "${REPO_ROOT}/polkit/com.bongbetic.fenris.monitor.policy" \
+    "${STAGE_DIR}/usr/share/polkit-1/actions/"
+
+# --- sysusers and tmpfiles fragments ---
+echo "  Installing sysusers/tmpfiles fragments ..."
+mkdir -p "${STAGE_DIR}/usr/lib/sysusers.d"
+install -m 0644 "${REPO_ROOT}/packaging/sysusers.d/fenris.conf" "${STAGE_DIR}/usr/lib/sysusers.d/"
+
+mkdir -p "${STAGE_DIR}/usr/lib/tmpfiles.d"
+install -m 0644 "${REPO_ROOT}/packaging/tmpfiles.d/fenris.conf" "${STAGE_DIR}/usr/lib/tmpfiles.d/"
+
+echo "Stage complete: ${STAGE_DIR}"

packaging/sysusers.d/fenris.conf

@@ -0,0 +1,3 @@
+# System user/group for Fenris observation store access
+# Created by systemd-sysusers during package install
+g fenris -

packaging/tmpfiles.d/fenris.conf

@@ -0,0 +1,2 @@
+# Type  Path              Mode  User   Group  Age  Argument
+d       /var/lib/fenris   2770  root   fenris  -   -

polkit/com.bongbetic.fenris.monitor.policy

@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE policyconfig PUBLIC
+ "-//freedesktop//DTD PolicyKit Policy Configuration 1.0//EN"
+ "http://www.freedesktop.org/standards/PolicyKit/1/policyconfig.dtd">
+<policyconfig>
+  <vendor>bongbetic</vendor>
+  <vendor_url>https://bongbetic.com</vendor_url>
+
+  <action id="com.bongbetic.fenris.monitor">
+    <description>Fenris Monitor Helper</description>
+    <message>Authentication is required to manage Fenris monitoring.</message>
+
+    <defaults>
+      <allow_any>no</allow_any>
+      <allow_inactive>no</allow_inactive>
+      <allow_active>auth_admin</allow_active>
+    </defaults>
+
+    <annotate key="org.freedesktop.policykit.imply">org.freedesktop.systemd1.manage-units</annotate>
+  </action>
+</policyconfig>

pyproject.toml

@@ -0,0 +1,23 @@
+[project]
+name = "fenris"
+version = "0.3.5"
+description = "NVMe wear monitor with persistent TUI"
+requires-python = ">=3.9"
+dependencies = [
+    "textual>=0.40.0",
+]
+
+[project.optional-dependencies]
+dev = [
+    "pytest>=7.0.0",
+    "pytest-cov>=4.0.0",
+    "pytest-asyncio>=0.20.0",
+]
+
+[tool.pytest.ini_options]
+testpaths = ["tests"]
+python_files = ["test_*.py"]
+python_functions = ["test_*"]
+markers = [
+    "slow: marks tests as slow",
+]

requirements.txt

@@ -0,0 +1,11 @@
+# Fenris dependency lockfile
+# Exact pins for reproducible installs (IN-8)
+# Refresh with: make update-deps
+textual==8.2.8
+rich==15.0.0
+markdown-it-py==4.2.0
+mdit-py-plugins==0.6.1
+mdurl==0.1.2
+platformdirs==4.11.7
+Pygments==2.21.0
+linkify-it-py==2.2.0

scripts/extract_changelog.py

@@ -0,0 +1,99 @@
+#!/usr/bin/env python3
+"""Extract one validated Keep a Changelog version section."""
+from __future__ import annotations
+
+import argparse
+from datetime import date
+from pathlib import Path
+import re
+import sys
+
+
+class ChangelogError(ValueError):
+    """A release cannot safely use the supplied changelog."""
+
+
+_SEMVER = r"(?:0|[1-9]\d*)\.(?:0|[1-9]\d*)\.(?:0|[1-9]\d*)"
+_VERSION_HEADING = re.compile(
+    rf"^## \[(?P<version>{_SEMVER})\] - (?P<date>.+)$", re.MULTILINE
+)
+
+
+def extract_version_section(changelog: str, version: str) -> str:
+    """Return *version*'s changelog section without altering its bytes.
+
+    The section ends immediately before the next level-two heading.  A release
+    cannot use an absent, empty, or malformed version section.
+    """
+    if not re.fullmatch(_SEMVER, version):
+        raise ChangelogError(f"requested version is not bare semver: {version!r}")
+
+    heading = next(
+        (match for match in _VERSION_HEADING.finditer(changelog)
+         if match.group("version") == version),
+        None,
+    )
+    if heading is None:
+        if re.search(rf"^## \[{re.escape(version)}\].*$", changelog, re.MULTILINE):
+            raise ChangelogError(f"version {version} has a malformed heading or date")
+        raise ChangelogError(f"version {version} is missing from the changelog")
+
+    heading_date = heading.group("date")
+    if not re.fullmatch(r"\d{4}-\d{2}-\d{2}", heading_date):
+        raise ChangelogError(f"version {version} has a malformed release date")
+    try:
+        date.fromisoformat(heading_date)
+    except ValueError as error:
+        raise ChangelogError(f"version {version} has a malformed release date") from error
+
+    next_heading = re.search(r"^## ", changelog[heading.end():], re.MULTILINE)
+    section_end = heading.end() + next_heading.start() if next_heading else len(changelog)
+    section = changelog[heading.start():section_end]
+    if not re.search(r"^- \S", section[heading.end() - heading.start():], re.MULTILINE):
+        raise ChangelogError(f"version {version} has an empty changelog section")
+    return section
+
+
+def extract_changelog(path: Path, version: str) -> str:
+    """Read and extract a requested version from a changelog file."""
+    try:
+        return extract_version_section(path.read_text(encoding="utf-8"), version)
+    except OSError as error:
+        raise ChangelogError(f"cannot read changelog {path}: {error.strerror}") from error
+
+
+def assemble_release_body(section: str, footer: str) -> str:
+    """Append standing guidance while preserving the extracted section verbatim."""
+    separator = "\n" if section.endswith("\n") else "\n\n"
+    return f"{section}{separator}{footer}"
+
+
+def main(argv: list[str] | None = None) -> int:
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument("changelog", type=Path)
+    parser.add_argument("version")
+    parser.add_argument(
+        "--footer",
+        type=Path,
+        help="append this standing release guidance after the extracted section",
+    )
+    args = parser.parse_args(argv)
+    try:
+        section = extract_changelog(args.changelog, args.version)
+        if args.footer:
+            try:
+                footer = args.footer.read_text(encoding="utf-8")
+            except OSError as error:
+                raise ChangelogError(
+                    f"cannot read release footer {args.footer}: {error.strerror}"
+                ) from error
+            section = assemble_release_body(section, footer)
+        sys.stdout.write(section)
+    except ChangelogError as error:
+        print(f"::error::{error}", file=sys.stderr)
+        return 1
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())

scripts/fenris

@@ -0,0 +1,227 @@
+#!/usr/bin/env python3
+"""fenris: unprivileged entry point for the Fenris TUI and CLI.
+
+With no arguments, opens the TUI.
+Subcommands route through fenris-monitor for privileged operations.
+
+Spec: §1.2, §8.4
+"""
+import argparse
+import os
+import subprocess
+import sys
+from pathlib import Path
+
+
+def add_runtime_packages() -> None:
+    """Make the package-owned, pure-Python dependencies importable.
+
+    RPM and deb installations deliberately use the target system's Python.
+    Their dependencies are vendored without a copied interpreter so a distro
+    Python minor-version update cannot leave Fenris linked to a removed ABI.
+    The legacy development install keeps its venv fallback.
+    """
+    runtime_dir = Path("/opt/fenris")
+    vendor_dir = runtime_dir / "vendor"
+    if vendor_dir.is_dir():
+        sys.path.insert(0, str(vendor_dir))
+        return
+
+    site_packages = next((runtime_dir / "lib").glob("python*/site-packages"), None)
+    if site_packages:
+        sys.path.insert(0, str(site_packages))
+
+
+add_runtime_packages()
+
+
+def is_root() -> bool:
+    """Check if running as root."""
+    return os.geteuid() == 0
+
+
+def run_monitor(*args: str) -> None:
+    """Run fenris-monitor with the given arguments.
+
+    If not root, re-exec under pkexec.
+    """
+    monitor_cmd = "/usr/libexec/fenris/fenris-monitor"
+
+    if is_root():
+        result = subprocess.run([monitor_cmd] + list(args))
+        sys.exit(result.returncode)
+    else:
+        # Use pkexec to elevate
+        pkexec = subprocess.run(
+            ["which", "pkexec"], capture_output=True
+        )
+        if pkexec.returncode != 0:
+            print(
+                "Error: No polkit agent available. "
+                "Run as root: sudo fenris-monitor ...",
+                file=sys.stderr,
+            )
+            sys.exit(1)
+        result = subprocess.run(["pkexec", monitor_cmd] + list(args))
+        sys.exit(result.returncode)
+
+
+def cmd_tui(args: argparse.Namespace) -> None:
+    """Open the TUI."""
+    from fenris.tui import run_tui
+    run_tui()
+
+
+def cmd_status(args: argparse.Namespace) -> None:
+    """Show status."""
+    from fenris.status import render_status
+    print(render_status())
+
+
+def cmd_sample(args: argparse.Namespace) -> None:
+    """Trigger on-demand collection."""
+    run_monitor("collect")
+
+
+def cmd_monitor_pause(args: argparse.Namespace) -> None:
+    """Pause monitoring."""
+    # Pause asks confirmation (§7.4)
+    if not args.yes:
+        response = input("Pause monitoring? [y/N] ")
+        if response.lower() not in ("y", "yes"):
+            print("Aborted.")
+            return
+
+    run_monitor("disable", "--now")
+
+
+def cmd_monitor_resume(args: argparse.Namespace) -> None:
+    """Resume monitoring."""
+    # Resume does not ask confirmation (§7.4)
+    run_monitor("enable", "--now")
+
+
+def cmd_baseline_set(args: argparse.Namespace) -> None:
+    """Set baseline."""
+    run_monitor("baseline", "set", args.baseline_json)
+
+
+def cmd_baseline_clear(args: argparse.Namespace) -> None:
+    """Clear baseline."""
+    run_monitor("baseline", "clear")
+
+
+def cmd_import(args: argparse.Namespace) -> None:
+    """Import legacy history."""
+    # This is a one-off migration, not a privileged operation
+    print("Legacy import: use fenris-import directly")
+
+
+def cmd_migrate(args: argparse.Namespace) -> None:
+    """Apply forward-only schema migrations (IN-5, IN-6).
+    
+    Called by 'sudo make upgrade'. Raises on newer-schema store.
+    """
+    from fenris.store import migrate_to_latest
+    from pathlib import Path
+
+    store_path = Path("/var/lib/fenris/observations.db")
+    if not store_path.exists():
+        print("No observation store found — nothing to migrate.")
+        return
+
+    steps = migrate_to_latest(store_path)
+    if steps:
+        print(f"Migration complete: {steps} step(s) applied.")
+    else:
+        print("Schema already current.")
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser(
+        prog="fenris",
+        description="Fenris NVMe endurance monitor",
+    )
+    parser.add_argument(
+        "--version", action="version", version="%(prog)s 0.3.0"
+    )
+
+    subparsers = parser.add_subparsers(dest="command")
+
+    # Default: TUI (no subcommand)
+    subparsers.add_parser("tui", help="Open the TUI (default)")
+
+    # Status
+    subparsers.add_parser("status", help="Show status")
+
+    # Sample (on-demand collection)
+    subparsers.add_parser("sample", help="Trigger on-demand collection")
+
+    # Monitor subcommand
+    monitor_parser = subparsers.add_parser("monitor", help="Monitor control")
+    monitor_sub = monitor_parser.add_subparsers(dest="monitor_action")
+
+    # monitor pause
+    pause_parser = monitor_sub.add_parser("pause", help="Pause monitoring")
+    pause_parser.add_argument(
+        "-y", "--yes", action="store_true", help="Skip confirmation"
+    )
+    pause_parser.set_defaults(func=cmd_monitor_pause)
+
+    # monitor resume
+    resume_parser = monitor_sub.add_parser("resume", help="Resume monitoring")
+    resume_parser.set_defaults(func=cmd_monitor_resume)
+
+    # Baseline subcommand
+    baseline_parser = subparsers.add_parser("baseline", help="Baseline operations")
+    baseline_sub = baseline_parser.add_subparsers(dest="baseline_action")
+
+    baseline_set = baseline_sub.add_parser("set", help="Set baseline")
+    baseline_set.add_argument("baseline_json", help="Baseline JSON data")
+    baseline_set.set_defaults(func=cmd_baseline_set)
+
+    baseline_clear = baseline_sub.add_parser("clear", help="Clear baseline")
+    baseline_clear.set_defaults(func=cmd_baseline_clear)
+
+    # Import
+    import_parser = subparsers.add_parser("import", help="Import legacy history")
+    import_parser.add_argument("path", help="Path to history.jsonl")
+    import_parser.set_defaults(func=cmd_import)
+
+    # Migrate (IN-5, IN-6) — called by upgrade, not for human use
+    migrate_parser = subparsers.add_parser("migrate", help=argparse.SUPPRESS)
+    migrate_parser.set_defaults(func=cmd_migrate)
+
+    # Rejected commands
+    for cmd in ["start", "stop", "run"]:
+        reject_parser = subparsers.add_parser(cmd, help=argparse.SUPPRESS)
+        reject_parser.set_defaults(func=lambda a: print(
+            f"'{cmd}' is not a valid command. "
+            f"Use 'fenris monitor resume' instead.",
+            file=sys.stderr,
+        ))
+
+    args = parser.parse_args()
+
+    if args.command is None or args.command == "tui":
+        cmd_tui(args)
+    elif args.command == "status":
+        cmd_status(args)
+    elif args.command == "sample":
+        cmd_sample(args)
+    elif args.command == "monitor":
+        if args.monitor_action is None:
+            monitor_parser.error("a subcommand is required")
+        args.func(args)
+    elif args.command == "baseline":
+        if args.baseline_action is None:
+            baseline_parser.error("a subcommand is required")
+        args.func(args)
+    elif args.command == "import":
+        cmd_import(args)
+    elif args.command == "migrate":
+        cmd_migrate(args)
+
+
+if __name__ == "__main__":
+    main()

scripts/release.sh

@@ -0,0 +1,206 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# Fenris one-command release flow (issue #52).
+# Builds both packages, signs, uploads to registry, creates release entry,
+# and attaches artifacts — or in dry-run mode, prints every command.
+#
+# Usage:
+#   scripts/release.sh --dry-run          # Print commands without executing
+#   scripts/release.sh --publish          # Execute the full release flow
+#
+# Environment:
+#   GITEA_TOKEN   - API token for Gitea registry and release API
+#   PACKAGING_KEY - GPG key UID (default: packaging@bongbetic.com)
+#
+# Spec: release-packaging.md §5
+
+# ── Defaults ─────────────────────────────────────────────────────────────
+
+DRY_RUN=false
+PUBLISH=false
+GITEA_URL="https://git.bongbetic.com"
+GITEA_OWNER="xavierk"
+GITEA_REPO="Fenris"
+PACKAGING_KEY="${PACKAGING_KEY:-packaging@bongbetic.com}"
+
+CODENAMES=(bookworm jammy noble)
+RPM_GROUP="fenris"
+
+# ── Parse arguments ──────────────────────────────────────────────────────
+
+for arg in "$@"; do
+    case "$arg" in
+        --dry-run) DRY_RUN=true ;;
+        --publish) PUBLISH=true ;;
+        --help|-h)
+            echo "Usage: $0 [--dry-run | --publish]"
+            echo ""
+            echo "Modes:"
+            echo "  --dry-run   Print commands without executing (default)"
+            echo "  --publish   Execute the full release flow"
+            echo ""
+            echo "Environment:"
+            echo "  GITEA_TOKEN   API token for Gitea registry and release API"
+            echo "  PACKAGING_KEY GPG key UID (default: packaging@bongbetic.com)"
+            exit 0
+            ;;
+        *)
+            echo "Unknown argument: $arg" >&2
+            echo "Usage: $0 [--dry-run | --publish]" >&2
+            exit 1
+            ;;
+    esac
+done
+
+if ! $DRY_RUN && ! $PUBLISH; then
+    DRY_RUN=true
+fi
+
+# ── Helpers ──────────────────────────────────────────────────────────────
+
+_version() {
+    sed -n 's/^version = "\(.*\)"/\1/p' pyproject.toml
+}
+
+_deb_name() {
+    local ver="$1"
+    echo "fenris_${ver}_amd64.deb"
+}
+
+_rpm_name() {
+    local ver="$1" rel="$2"
+    echo "fenris-${ver}-${rel}.x86_64.rpm"
+}
+
+_run() {
+    if $DRY_RUN; then
+        echo "  $*"
+    else
+        eval "$@"
+    fi
+}
+
+# ── Main ─────────────────────────────────────────────────────────────────
+
+VERSION=$(_version)
+REVISION=1
+DEB=$(_deb_name "$VERSION")
+RPM=$(_rpm_name "$VERSION" "$REVISION")
+
+echo "=== Fenris Release v${VERSION} ==="
+echo ""
+
+if $DRY_RUN; then
+    echo "[dry-run] Commands below will be executed in --publish mode."
+    echo ""
+fi
+
+# ── Step 1: Build both formats ──────────────────────────────────────────
+
+echo "--- Build packages ---"
+_run "make package"
+echo ""
+
+# ── Step 2: Sign RPM payload ────────────────────────────────────────────
+
+echo "--- Sign RPM payload ---"
+_run "rpmsign --addsign --define '_gpg_name ${PACKAGING_KEY}' dist/${RPM}"
+echo ""
+
+# ── Step 3: Generate and clearsign SHA256SUMS ────────────────────────────
+
+echo "--- Generate SHA256SUMS ---"
+_run "cd dist && sha256sum ${DEB} ${RPM} > SHA256SUMS"
+echo ""
+
+echo "--- Clearsign SHA256SUMS ---"
+_run "gpg --batch --yes --clearsign --local-user ${PACKAGING_KEY} dist/SHA256SUMS"
+echo ""
+
+# ── Step 4: Upload to Gitea package registry ─────────────────────────────
+
+echo "--- Upload packages to registry ---"
+for codename in "${CODENAMES[@]}"; do
+    _run "curl --fail -X PUT -u ${GITEA_OWNER}:\$GITEA_TOKEN -T dist/${DEB} '${GITEA_URL}/api/packages/${GITEA_OWNER}/debian/pool/${codename}/main/upload'"
+done
+_run "curl --fail -X PUT -u ${GITEA_OWNER}:\$GITEA_TOKEN -T dist/${RPM} '${GITEA_URL}/api/packages/${GITEA_OWNER}/rpm/${RPM_GROUP}/upload'"
+echo ""
+
+# ── Step 5: Create Gitea release with notes ─────────────────────────────
+
+echo "--- Create Gitea release ---"
+_release_notes="Release v${VERSION}
+
+## Packages
+
+Install via apt (Debian/Ubuntu):
+
+\`\`\`bash
+curl --fail -fsSL https://git.bongbetic.com/${GITEA_OWNER}/${GITEA_REPO}/raw/branch/main/packaging/keys/fenris-packaging.asc | sudo gpg --dearmor -o /etc/apt/keyrings/fenris.asc
+echo \"deb [signed-by=/etc/apt/keyrings/fenris.asc] https://git.bongbetic.com/api/packages/${GITEA_OWNER}/debian bookworm main\" | sudo tee /etc/apt/sources.list.d/fenris.list
+sudo apt update && sudo apt install fenris
+\`\`\`
+
+Install via dnf (Fedora):
+
+\`\`\`bash
+sudo dnf config-manager --add-repo https://git.bongbetic.com/${GITEA_OWNER}/${GITEA_REPO}/raw/branch/main/packaging/fenris.repo
+sudo dnf install fenris
+\`\`\`
+
+## Verification
+
+\`\`\`bash
+rpm -Kv fenris-${VERSION}-1.x86_64.rpm
+gpg --verify SHA256SUMS.asc SHA256SUMS
+\`\`\`
+
+## Artifacts
+
+- \`dist/${DEB}\` (Debian/Ubuntu)
+- \`dist/${RPM}\` (Fedora)
+- \`dist/SHA256SUMS.asc\` (clearsigned checksums)
+
+See [docs/install/signing-key-ceremony.md](docs/install/signing-key-ceremony.md) for key ceremony details.
+See [docs/install/migrate-from-makeinstall.md](docs/install/migrate-from-makeinstall.md) for migration from make install."
+
+if $DRY_RUN; then
+    _run "curl --fail -X POST -u ${GITEA_OWNER}:\$GITEA_TOKEN -H 'Content-Type: application/json' -d '{\"tag_name\":\"v${VERSION}\",\"name\":\"v${VERSION}\",\"body\":\"...\"}' '${GITEA_URL}/api/v1/repos/${GITEA_OWNER}/${GITEA_REPO}/releases'"
+else
+    # Create release via Gitea API (creates the tag atomically — no bare tag)
+    RELEASE_RESPONSE=$(curl --fail -s -X POST \
+        -u "${GITEA_OWNER}:${GITEA_TOKEN}" \
+        -H "Content-Type: application/json" \
+        -d "$(jq -n \
+            --arg tag "v${VERSION}" \
+            --arg name "v${VERSION}" \
+            --arg body "$_release_notes" \
+            '{tag_name: $tag, name: $name, body: $body}')" \
+        "${GITEA_URL}/api/v1/repos/${GITEA_OWNER}/${GITEA_REPO}/releases")
+
+    RELEASE_ID=$(echo "$RELEASE_RESPONSE" | jq -r '.id')
+    echo "  Release created: ${GITEA_URL}/${GITEA_OWNER}/${GITEA_REPO}/releases/tag/v${VERSION}"
+fi
+echo ""
+
+# ── Step 6: Attach artifacts to release ──────────────────────────────────
+
+echo "--- Attach artifacts to release ---"
+for artifact in "dist/${DEB}" "dist/${RPM}" "dist/SHA256SUMS.asc"; do
+    _run "curl --fail -X POST -u ${GITEA_OWNER}:\$GITEA_TOKEN -F 'attachment=@${artifact}' '${GITEA_URL}/api/v1/repos/${GITEA_OWNER}/${GITEA_REPO}/releases/${RELEASE_ID:-0}/assets'"
+done
+echo ""
+
+# ── Done ─────────────────────────────────────────────────────────────────
+
+echo "=== Release v${VERSION} complete ==="
+echo ""
+echo "Summary:"
+echo "  Packages: ${DEB}, ${RPM}"
+echo "  Checksums: dist/SHA256SUMS.asc"
+echo "  Registry: deb → bookworm, jammy, noble; rpm → ${RPM_GROUP}"
+echo "  Release: ${GITEA_URL}/${GITEA_OWNER}/${GITEA_REPO}/releases/tag/v${VERSION}"
+echo ""
+echo "Key ceremony: delete the private key after release."
+echo "  See docs/install/signing-key-ceremony.md"

scripts/release_request.py

@@ -0,0 +1,70 @@
+#!/usr/bin/env python3
+"""Describe the Gitea request that creates or resynchronizes a release."""
+from __future__ import annotations
+
+import argparse
+import json
+from pathlib import Path
+import re
+import sys
+from typing import Any
+
+
+_SEMVER = r"(?:0|[1-9]\d*)\.(?:0|[1-9]\d*)\.(?:0|[1-9]\d*)"
+
+
+class ReleaseRequestError(ValueError):
+    """A release request could not be prepared safely."""
+
+
+def build_release_request(
+    version: str, body: str, existing_release: dict[str, Any] | None
+) -> dict[str, Any]:
+    """Return the observable POST or PATCH request for a Gitea release."""
+    if not re.fullmatch(_SEMVER, version):
+        raise ReleaseRequestError(f"version is not bare semver: {version!r}")
+    if existing_release is None:
+        return {
+            "method": "POST",
+            "path": "/releases",
+            "payload": {"tag_name": f"v{version}", "name": f"v{version}", "body": body},
+        }
+
+    release_id = existing_release.get("id")
+    if not isinstance(release_id, int):
+        raise ReleaseRequestError("existing release does not contain an integer id")
+    return {
+        "method": "PATCH",
+        "path": f"/releases/{release_id}",
+        "payload": {"body": body},
+    }
+
+
+def _read_json(path: Path) -> dict[str, Any]:
+    try:
+        value = json.loads(path.read_text(encoding="utf-8"))
+    except (OSError, json.JSONDecodeError) as error:
+        raise ReleaseRequestError(f"cannot read existing release {path}: {error}") from error
+    if not isinstance(value, dict):
+        raise ReleaseRequestError("existing release must be a JSON object")
+    return value
+
+
+def main(argv: list[str] | None = None) -> int:
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument("--version", required=True)
+    parser.add_argument("--body-file", type=Path, required=True)
+    parser.add_argument("--existing-release", type=Path)
+    args = parser.parse_args(argv)
+    try:
+        body = args.body_file.read_text(encoding="utf-8")
+        existing = _read_json(args.existing_release) if args.existing_release else None
+        print(json.dumps(build_release_request(args.version, body, existing)))
+    except (OSError, ReleaseRequestError) as error:
+        print(f"::error::{error}", file=sys.stderr)
+        return 1
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())

scripts/xbps-publish.sh

@@ -0,0 +1,170 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# Fenris XBPS publication script (issue #83).
+# Builds, signs, and publishes XBPS packages to the Fenris-xbps repository.
+#
+# Usage:
+#   scripts/xbps-publish.sh --dry-run          # Print commands without executing
+#   scripts/xbps-publish.sh --publish          # Execute the full publication flow
+#
+# Environment:
+#   XBPS_SIGNING_KEY - Path to SSH RSA private key for XBPS signing
+#                      (default: ~/.ssh/id_xbps)
+#   SIGNED_BY        - Signature identity string
+#                      (default: "Fenris Packaging <packaging@bongbetic.com>")
+#
+# Spec: native-void-support.md, ADR 0008
+
+# ── Defaults ─────────────────────────────────────────────────────────────
+
+DRY_RUN=false
+PUBLISH=false
+GITEA_URL="https://git.bongbetic.com"
+GITEA_OWNER="xavierk"
+GITEA_REPO="Fenris-xbps"
+GITEA_BRANCH="stable"
+ARCH="x86_64"
+XBPS_SIGNING_KEY="${XBPS_SIGNING_KEY:-$HOME/.ssh/id_xbps}"
+SIGNED_BY="${SIGNED_BY:-Fenris Packaging <packaging@bongbetic.com>}"
+
+# ── Parse arguments ──────────────────────────────────────────────────────
+
+for arg in "$@"; do
+    case "$arg" in
+        --dry-run) DRY_RUN=true ;;
+        --publish) PUBLISH=true ;;
+        --help|-h)
+            echo "Usage: $0 [--dry-run | --publish]"
+            echo ""
+            echo "Modes:"
+            echo "  --dry-run   Print commands without executing (default)"
+            echo "  --publish   Execute the full publication flow"
+            echo ""
+            echo "Environment:"
+            echo "  XBPS_SIGNING_KEY  Path to SSH RSA private key (default: ~/.ssh/id_rsa)"
+            echo "  SIGNED_BY         Signature identity (default: Fenris Packaging <packaging@bongbetic.com>)"
+            exit 0
+            ;;
+        *)
+            echo "Unknown argument: $arg" >&2
+            echo "Usage: $0 [--dry-run | --publish]" >&2
+            exit 1
+            ;;
+    esac
+done
+
+if ! $DRY_RUN && ! $PUBLISH; then
+    DRY_RUN=true
+fi
+
+# ── Helpers ──────────────────────────────────────────────────────────────
+
+_version() {
+    sed -n 's/^version = "\(.*\)"/\1/p' pyproject.toml
+}
+
+_run() {
+    if $DRY_RUN; then
+        echo "  $*"
+    else
+        eval "$@"
+    fi
+}
+
+# ── Pre-flight checks ───────────────────────────────────────────────────
+
+if [[ ! -f "$XBPS_SIGNING_KEY" ]]; then
+    echo "ERROR: Signing key not found at $XBPS_SIGNING_KEY" >&2
+    echo "Generate one with: ssh-keygen -t rsa -b 3072 -f $XBPS_SIGNING_KEY" >&2
+    exit 1
+fi
+
+for tool in xbps-create xbps-rindex git; do
+    if ! command -v "$tool" &>/dev/null; then
+        echo "ERROR: Required tool not found: $tool" >&2
+        exit 1
+    done
+done
+
+# ── Main ─────────────────────────────────────────────────────────────────
+
+VERSION=$(_version)
+REVISION=1
+PKGVER="fenris-${VERSION}_${REVISION}"
+XBPS_FILE="${PKGVER}.${ARCH}.xbps"
+
+echo "=== Fenris XBPS Publication v${VERSION} ==="
+echo ""
+
+if $DRY_RUN; then
+    echo "[dry-run] Commands below will be executed in --publish mode."
+    echo ""
+fi
+
+# ── Step 1: Build XBPS package ───────────────────────────────────────────
+
+echo "--- Build XBPS package ---"
+_run "make stage"
+_run "xbps-create -A ${ARCH} -n ${PKGVER} -s 'Fenris NVMe wear monitor' -S 'NVMe wear monitor with persistent TUI' -m 'Fenris Packaging <packaging@bongbetic.com>' -H 'https://git.bongbetic.com/xavierk/Fenris' -l 'MIT' build/stage"
+echo ""
+
+# ── Step 2: Sign package ─────────────────────────────────────────────────
+
+echo "--- Sign XBPS package ---"
+_run "xbps-rindex --sign-pkg --privkey ${XBPS_SIGNING_KEY} ${XBPS_FILE}"
+echo ""
+
+# ── Step 3: Clone/update distribution repository ─────────────────────────
+
+echo "--- Prepare distribution repository ---"
+WORK_DIR=$(mktemp -d)
+_run "git clone ${GITEA_URL}/${GITEA_OWNER}/${GITEA_REPO}.git ${WORK_DIR}"
+_run "cd ${WORK_DIR} && git checkout ${GITEA_BRANCH}"
+_run "mkdir -p ${WORK_DIR}/${ARCH}"
+echo ""
+
+# ── Step 4: Copy artifacts and update index ──────────────────────────────
+
+echo "--- Update repository index ---"
+_run "cp ${XBPS_FILE} ${XBPS_FILE}.sig2 ${WORK_DIR}/${ARCH}/"
+_run "cd ${WORK_DIR} && xbps-rindex --add ${ARCH}/${XBPS_FILE}"
+_run "cd ${WORK_DIR} && xbps-rindex --sign --privkey ${XBPS_SIGNING_KEY} --signedby '${SIGNED_BY}' ${ARCH}"
+echo ""
+
+# ── Step 5: Commit and push ──────────────────────────────────────────────
+
+echo "--- Commit and push ---"
+_run "cd ${WORK_DIR} && git add -A"
+_run "cd ${WORK_DIR} && git commit -m 'Release fenris ${VERSION}'"
+_run "cd ${WORK_DIR} && git push origin ${GITEA_BRANCH}"
+echo ""
+
+# ── Step 6: Verify publication ───────────────────────────────────────────
+
+echo "--- Verify publication ---"
+RAW_URL="${GITEA_URL}/${GITEA_OWNER}/${GITEA_REPO}/raw/branch/${GITEA_BRANCH}/${ARCH}/x86_64-repodata"
+_run "curl -sI '${RAW_URL}' | head -5"
+echo ""
+
+# ── Cleanup ──────────────────────────────────────────────────────────────
+
+if $PUBLISH; then
+    rm -rf "${WORK_DIR}"
+fi
+
+# ── Done ─────────────────────────────────────────────────────────────────
+
+echo "=== XBPS Publication v${VERSION} complete ==="
+echo ""
+echo "Summary:"
+echo "  Package: ${XBPS_FILE}"
+echo "  Repository: ${GITEA_URL}/${GITEA_OWNER}/${GITEA_REPO}"
+echo "  Branch: ${GITEA_BRANCH}"
+echo "  Repository URL: https://git.bongbetic.com/${GITEA_OWNER}/${GITEA_REPO}/raw/branch/${GITEA_BRANCH}/${ARCH}"
+echo ""
+echo "Client installation:"
+echo "  sudo xbps-install -S https://git.bongbetic.com/${GITEA_OWNER}/${GITEA_REPO}/raw/branch/${GITEA_BRANCH}/${ARCH}"
+echo ""
+echo "Key ceremony: delete the private key after publication."
+echo "  See docs/install/signing-key-ceremony.md"

src/fenris/__init__.py

@@ -0,0 +1,2 @@
+"""Fenris: NVMe wear monitor with persistent TUI."""
+__version__ = "0.3.1"

src/fenris/collect.py

@@ -0,0 +1,137 @@
+#!/usr/bin/env python3
+"""fenris-collect: device interrogation and store writes.
+
+This is the root oneshot unit's ExecStart. It reads the device selector
+from /etc/fenris/fenris.conf, interrogates the drive via smartctl and sysfs,
+and writes the sample to the observation store.
+
+Spec: §8.4, §8.5
+
+When run as a script, uses the fenris package from the installed wheel.
+"""
+import json
+import subprocess
+import sys
+from datetime import datetime, timezone
+from pathlib import Path
+
+# Package dependencies are vendored independently of the host Python minor
+# version.  Keep the venv fallback for the legacy development install.
+VENV_DIR = Path("/opt/fenris")
+if VENV_DIR.exists():
+    vendor_dir = VENV_DIR / "vendor"
+    if vendor_dir.is_dir():
+        sys.path.insert(0, str(vendor_dir))
+    else:
+        site_packages = next((VENV_DIR / "lib").glob("python*/site-packages"), None)
+        if site_packages:
+            sys.path.insert(0, str(site_packages))
+
+from fenris.store import init_store, get_store_path
+from fenris.collector import run_collection
+
+
+CONFIG_PATH = Path("/etc/fenris/fenris.conf")
+
+
+def load_config() -> dict:
+    """Load configuration from /etc/fenris/fenris.conf.
+
+    The file holds exactly one key: the device selector.
+    Spec §8.3: re-read every run; no reload path.
+    """
+    if not CONFIG_PATH.exists():
+        raise RuntimeError(f"Configuration file not found: {CONFIG_PATH}")
+
+    config = {}
+    try:
+        with open(CONFIG_PATH, "r") as f:
+            for line in f:
+                line = line.strip()
+                if not line or line.startswith("#"):
+                    continue
+                if "=" in line:
+                    key, value = line.split("=", 1)
+                    config[key.strip()] = value.strip()
+    except Exception as e:
+        raise RuntimeError(f"Failed to read configuration: {e}")
+
+    if "device" not in config:
+        raise RuntimeError("Configuration error: missing 'device' key")
+
+    return config
+
+
+def interrogate_drive(device: str) -> dict:
+    """Interrogate the drive via smartctl.
+
+    Returns the smartctl JSON output.
+    Raises RuntimeError on failure.
+    """
+    result = subprocess.run(
+        ["smartctl", "-a", "-j", device],
+        capture_output=True,
+        text=True,
+    )
+
+    if result.returncode != 0:
+        raise RuntimeError(
+            f"smartctl failed for {device}: {result.stderr}"
+        )
+
+    try:
+        return json.loads(result.stdout)
+    except json.JSONDecodeError as e:
+        raise RuntimeError(f"Failed to parse smartctl output: {e}")
+
+
+def find_nvme_sysfs() -> Path | None:
+    """Find the NVMe controller sysfs path."""
+    nvme_ctrl = Path("/sys/class/nvme")
+    if not nvme_ctrl.exists():
+        return None
+
+    for ctrl in sorted(nvme_ctrl.iterdir()):
+        if ctrl.name.startswith("nvme"):
+            return ctrl
+    return None
+
+
+def main() -> None:
+    """Run one collection cycle."""
+    try:
+        config = load_config()
+        device = config["device"]
+
+        # Interrogate the drive
+        smartctl_data = interrogate_drive(device)
+
+        # Find sysfs path
+        sysfs_path = find_nvme_sysfs()
+        if sysfs_path is None:
+            raise RuntimeError("No NVMe controller found in sysfs")
+
+        # Inject a simple clock
+        class SimpleClock:
+            def utcnow(self):
+                return datetime.now(timezone.utc)
+
+        clock = SimpleClock()
+
+        # Run collection
+        result = run_collection(smartctl_data, sysfs_path, config, clock)
+
+        if result["ok"]:
+            print(f"Collection successful: {result['sample_count']} sample(s)")
+            sys.exit(0)
+        else:
+            print(f"Collection failed: {result['error']}", file=sys.stderr)
+            sys.exit(1)
+
+    except Exception as e:
+        print(f"Collection error: {e}", file=sys.stderr)
+        sys.exit(1)
+
+
+if __name__ == "__main__":
+    main()

src/fenris/collector.py

@@ -0,0 +1,360 @@
+"""Collector: acquires counters and identity, writes to observation store.
+
+This module implements the thinnest complete write path:
+- Acquire counters and thermal evidence from smartctl -a -j
+- Acquire controller identity from sysfs
+- Normalize identity exactly once at write time
+- Validate every row against store invariants
+- Commit one well-formed sample
+
+No code path outside the collector interrogates the device.
+"""
+import json
+import sqlite3
+from datetime import datetime, timezone
+from pathlib import Path
+from typing import Any, Dict, Optional, Tuple
+
+from .store import init_store, get_store_path
+from .monitoring_periods import ensure_period_open
+from .derive import find_previous_sample, derive_hours_from_interval
+
+
+class AcquisitionError(Exception):
+    """Raised when acquisition fails - whole run is refused."""
+    pass
+
+
+class InvariantViolationError(Exception):
+    """Raised when a row would violate store invariants - writes nothing."""
+    pass
+
+
+def acquire_from_smartctl(smartctl_data: Dict[str, Any]) -> Dict[str, Any]:
+    """Acquire counters and thermal evidence from smartctl -a -j data.
+    
+    Validates that all required fields are present.
+    Raises AcquisitionError on any failure.
+    """
+    required_fields = [
+        "nvme_smart_health_information_log",
+        "user_capacity",
+        "model_name",
+        "serial_number",
+        "firmware_version",
+    ]
+    
+    for field in required_fields:
+        if field not in smartctl_data:
+            raise AcquisitionError(f"Missing required field in smartctl data: {field}")
+    
+    log = smartctl_data["nvme_smart_health_information_log"]
+    required_log_fields = [
+        "data_units_written",
+        "data_units_read",
+        "percentage_used",
+        "power_on_hours",
+        "temperature",
+    ]
+    
+    for field in required_log_fields:
+        if field not in log:
+            raise AcquisitionError(f"Missing required field in SMART log: {field}")
+    
+    return {
+        "model": smartctl_data["model_name"],
+        "serial": smartctl_data["serial_number"],
+        "firmware_rev": smartctl_data["firmware_version"],
+        "capacity_bytes": smartctl_data["user_capacity"]["bytes"],
+        "percentage_used": log["percentage_used"],
+        "available_spare": log.get("available_spare"),
+        "media_errors": log.get("media_errors", 0),
+        "power_on_hours": log["power_on_hours"],
+        "power_cycles": log.get("power_cycles"),
+        "unsafe_shutdowns": log.get("unsafe_shutdowns"),
+        "temperature_c": log["temperature"],
+        "data_units_written": log["data_units_written"],
+        "data_units_read": log["data_units_read"],
+        "bytes_written": log["data_units_written"] * 512000,
+        "bytes_read": log["data_units_read"] * 512000,
+        "critical_warning": log.get("critical_warning", 0),
+    }
+
+
+def acquire_from_sysfs(sysfs_path: Path) -> Dict[str, Any]:
+    """Acquire controller identity from sysfs.
+    
+    Reads identity from:
+    - /sys/class/nvme/<ctrl>/subsysnqn (primary)
+    - /sys/class/nvme/<ctrl>/model
+    - /sys/class/nvme/<ctrl>/serial
+    - /sys/class/nvme/<ctrl>/firmware_rev
+    - /sys/class/nvme/<ctrl>/transport/ (optional)
+    
+    Raises AcquisitionError on any failure.
+    """
+    identity_files = {
+        "subnqn": "subsysnqn",
+        "mn": "model",
+        "sn": "serial",
+        "fr": "firmware_rev",
+    }
+    
+    identity = {}
+    for key, filename in identity_files.items():
+        filepath = sysfs_path / filename
+        if not filepath.exists():
+            raise AcquisitionError(f"Missing sysfs file: {filepath}")
+        
+        try:
+            value = filepath.read_text().strip()
+            identity[key] = value if value else ""
+        except Exception as e:
+            raise AcquisitionError(f"Failed to read {filepath}: {e}")
+    
+    # Transport info (optional)
+    transport_dir = sysfs_path / "transport"
+    if transport_dir.exists():
+        try:
+            transport_file = transport_dir / "trstring"
+            if transport_file.exists():
+                identity["transport"] = transport_file.read_text().strip()
+            else:
+                identity["transport"] = None
+        except Exception:
+            identity["transport"] = None
+    else:
+        identity["transport"] = None
+    
+    # vid/ssvid from PCI node (optional, metadata only - never key components)
+    # PCI device directory is the sysfs_path itself (the controller dir is a symlink to PCI)
+    pci_device = sysfs_path
+    for attr, key in [("vendor", "vid"), ("subsystem_vendor", "ssvid")]:
+        filepath = pci_device / attr
+        if filepath.exists():
+            try:
+                value = filepath.read_text().strip()
+                identity[key] = value if value else None
+            except Exception:
+                identity[key] = None
+        else:
+            identity[key] = None
+    
+    return identity
+
+
+def normalize_identity(identity: Dict[str, Any]) -> str:
+    """Normalize identity exactly once at write time.
+    
+    Rules:
+    - Strip trailing spaces and newlines
+    - No case folding
+    - Empty-after-strip stored blank
+    
+    Returns normalized identity key.
+    """
+    # Primary key: normalized kernel-exposed subsystem NQN
+    key = identity.get("subnqn", "")
+    if key:
+        key = key.rstrip()
+        return key
+    
+    # Fallback 1: kernel composite (not implemented yet)
+    # Fallback 2: model|serial
+    mn = identity.get("mn", "").rstrip()
+    sn = identity.get("sn", "").rstrip()
+    if mn or sn:
+        return f"{mn}|{sn}"
+    
+    # All keys blank - degraded identity
+    return ""
+
+
+def compute_identity_degraded(identity: Dict[str, Any]) -> bool:
+    """Check if identity is degraded (all key rungs empty)."""
+    key = normalize_identity(identity)
+    return key == ""
+
+
+def validate_sample_invariants(sample: Dict[str, Any], conn: sqlite3.Connection) -> None:
+    """Validate sample against store invariants.
+    
+    Raises InvariantViolationError if any invariant is violated.
+    """
+    # TODO: Implement more complex invariants as needed
+    # For now, just check basic constraints
+    
+    if sample.get("bytes_written", 0) < 0:
+        raise InvariantViolationError("Negative bytes_written")
+    
+    if sample.get("bytes_read", 0) < 0:
+        raise InvariantViolationError("Negative bytes_read")
+
+
+def write_sample(
+    sample: Dict[str, Any],
+    identity: Dict[str, Any],
+    conn: sqlite3.Connection,
+    clock,
+) -> Dict[str, Any]:
+    """Write one sample to the observation store.
+    
+    Identity normalization happens exactly once here.
+    Returns segment info for the caller.
+    """
+    from .segment import find_current_segment, should_open_new_segment, open_segment
+    
+    # Normalize identity exactly once at write time
+    identity_key = normalize_identity(identity)
+    identity_degraded = compute_identity_degraded(identity)
+    
+    # Find current segment
+    current_segment = find_current_segment(conn)
+    
+    # Determine if we need a new segment
+    should_open, reason = should_open_new_segment(
+        current_segment, identity_key, sample["bytes_written"], conn
+    )
+    
+    # Open new segment if needed
+    segment_opened = False
+    if should_open:
+        now = clock.utcnow()
+        open_segment(conn, now, identity, identity_key, identity_degraded)
+        segment_opened = True
+    
+    # Get current segment_id for provenance
+    current_segment = find_current_segment(conn)
+    segment_id = current_segment["id"] if current_segment else None
+    
+    # Insert sample with segment_id
+    cursor = conn.execute(
+        """
+        INSERT INTO samples (
+            ts, device, subnqn, sn, mn, fr, capacity_bytes,
+            percentage_used, available_spare, media_errors, power_on_hours,
+            power_cycles, unsafe_shutdowns, temperature_c,
+            data_units_written, data_units_read, bytes_written, bytes_read,
+            critical_warning, segment_id
+        ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+        """,
+        (
+            sample["ts"],
+            sample["device"],
+            identity.get("subnqn", ""),
+            identity.get("sn", ""),
+            identity.get("mn", ""),
+            identity.get("fr", ""),
+            sample["capacity_bytes"],
+            sample["percentage_used"],
+            sample["available_spare"],
+            sample["media_errors"],
+            sample["power_on_hours"],
+            sample["power_cycles"],
+            sample["unsafe_shutdowns"],
+            sample["temperature_c"],
+            sample["data_units_written"],
+            sample["data_units_read"],
+            sample["bytes_written"],
+            sample["bytes_read"],
+            sample["critical_warning"],
+            segment_id,
+        ),
+    )
+    
+    conn.commit()
+    
+    return {
+        "segment_opened": segment_opened,
+        "segment_reason": reason,
+        "identity_key": identity_key,
+        "identity_degraded": identity_degraded,
+        "segment_id": segment_id,
+    }
+
+
+def run_collection(
+    smartctl_data: Dict[str, Any],
+    sysfs_path: Path,
+    config: Dict[str, Any],
+    clock,
+) -> Dict[str, Any]:
+    """Run one collection run.
+    
+    This is the main entry point for the collector.
+    Returns the run outcome.
+    """
+    try:
+        # Acquire counters and thermal evidence
+        counters = acquire_from_smartctl(smartctl_data)
+        
+        # Acquire controller identity
+        identity = acquire_from_sysfs(sysfs_path)
+        
+        # Build sample with injected clock
+        sample = {
+            "ts": clock.utcnow().isoformat(),
+            "device": config["device"],
+            **counters,
+            **identity,
+        }
+        
+        # Initialize store if needed
+        store_path = get_store_path(config)
+        conn = init_store(store_path)
+
+        # Run legacy import if needed (idempotent)
+        from .legacy import import_legacy_history
+        history_path = Path(config.get("data_dir", ".")) / "history.jsonl"
+        if history_path.exists():
+            import_legacy_history(conn, history_path, clock=clock)
+
+        
+        try:
+            # Ensure monitoring period is open (issue #73 AC2)
+            ensure_period_open(conn, clock.utcnow())
+            
+            # Validate invariants
+            validate_sample_invariants(sample, conn)
+            
+            # Write sample and get segment info
+            seg_info = write_sample(sample, identity, conn, clock)
+            
+            # Derive hour observations from interval with previous sample
+            try:
+                # Find the sample we just wrote
+                cursor = conn.execute("SELECT id FROM samples ORDER BY id DESC LIMIT 1")
+                current_id = cursor.fetchone()[0]
+                
+                prev = find_previous_sample(conn, seg_info.get("segment_id"), current_id)
+                if prev is not None:
+                    # Build current sample dict for derivation
+                    current = {
+                        "id": current_id,
+                        "ts": sample["ts"],
+                        "bytes_written": sample["bytes_written"],
+                        "bytes_read": sample["bytes_read"],
+                        "power_on_hours": sample["power_on_hours"],
+                        "temperature_c": sample["temperature_c"],
+                        "data_units_written": sample["data_units_written"],
+                        "data_units_read": sample["data_units_read"],
+                    }
+                    derive_hours_from_interval(conn, prev, current)
+            except Exception:
+                # Derivation failure must not prevent sample persistence (issue #73 AC6)
+                pass
+            
+            return {
+                "ok": True,
+                "sample_count": 1,
+                "store_path": str(store_path),
+            }
+        finally:
+            conn.close()
+    
+    except (AcquisitionError, InvariantViolationError) as e:
+        return {
+            "ok": False,
+            "error": str(e),
+            "error_type": type(e).__name__,
+        }

src/fenris/day_aggregate.py

@@ -0,0 +1,165 @@
+"""Day aggregate derivation per spec §5.4, §3.3.
+
+One row per UTC day, derived monotonically from hour rows — the grain at
+which usage-habit evidence is judged.  No absent hour is ever interpolated,
+estimated, or fabricated (§5.3, FL-3).
+
+Coverage: the share of wall-clock seconds inside monitoring periods whose
+usage-habit classification is known rather than unknown (§5.3).
+"""
+import sqlite3
+from dataclasses import dataclass
+from datetime import datetime, timedelta, timezone
+
+
+@dataclass(frozen=True)
+class DayAggregate:
+    """One UTC day's aggregated stats."""
+    day: str  # ISO 8601 UTC date, e.g. "2026-09-01"
+    seconds_active: int
+    seconds_idle: int
+    seconds_powered_off: int
+    seconds_unknown: int
+    bytes_written_delta: int
+    bytes_read_delta: int
+    sample_count: int
+    coverage: float
+
+
+def _period_wall_clock_for_day(conn: sqlite3.Connection, day: str) -> int:
+    """Total wall-clock seconds inside monitoring periods for a UTC day.
+
+    Clamps each period to the day boundary [dayT00:00, dayT24:00).
+    """
+    day_start = datetime.fromisoformat(f"{day}T00:00:00+00:00")
+    day_end = day_start + timedelta(days=1)
+    day_start_str = day_start.isoformat()
+    day_end_str = day_end.isoformat()
+
+    cursor = conn.execute(
+        "SELECT started_at, ended_at FROM monitoring_periods "
+        "WHERE (ended_at IS NULL OR ended_at > ?) AND started_at < ? "
+        "ORDER BY started_at",
+        (day_start_str, day_end_str),
+    )
+
+    total = 0
+    for row in cursor.fetchall():
+        period_start = row[0]
+        period_end = row[1]
+
+        effective_start = max(period_start, day_start_str)
+        if period_end is not None:
+            effective_end = min(period_end, day_end_str)
+        else:
+            effective_end = day_end_str
+
+        if effective_start < effective_end:
+            s = datetime.fromisoformat(effective_start)
+            e = datetime.fromisoformat(effective_end)
+            total += int((e - s).total_seconds())
+
+    return total
+
+
+def _hour_overlaps_period(conn: sqlite3.Connection, hour_iso: str) -> bool:
+    """Check if an hour's wall-clock span overlaps any monitoring period."""
+    hour_start = datetime.fromisoformat(hour_iso)
+    hour_end = hour_start + timedelta(hours=1)
+    hs = hour_start.isoformat()
+    he = hour_end.isoformat()
+
+    cursor = conn.execute(
+        "SELECT 1 FROM monitoring_periods "
+        "WHERE started_at < ? AND (ended_at IS NULL OR ended_at > ?) "
+        "LIMIT 1",
+        (he, hs),
+    )
+    return cursor.fetchone() is not None
+
+
+def derive_day(conn: sqlite3.Connection, day: str) -> DayAggregate | None:
+    """Derive a single day aggregate from its hour rows + monitoring periods.
+
+    Only hours overlapping a monitoring period contribute to the aggregate.
+    Gap hours inside periods contribute unknown seconds.  Hours outside all
+    monitoring periods are excluded entirely (§5.2).
+
+    Returns None if no hours exist for the day.
+    """
+    cursor = conn.execute(
+        "SELECT hour, active_seconds, idle_seconds, powered_off_seconds, unknown_seconds, "
+        "       bytes_written_delta, bytes_read_delta, sample_count "
+        "FROM hour_observations "
+        "WHERE hour LIKE ? "
+        "ORDER BY hour",
+        (day + "T%",),
+    )
+    rows = cursor.fetchall()
+    if not rows:
+        return None
+
+    total_active = 0
+    total_idle = 0
+    total_powered_off = 0
+    total_unknown_from_hours = 0
+    total_bw = 0
+    total_br = 0
+    total_samples = 0
+    total_hour_wall_clock = 0
+
+    for row in rows:
+        # Only count hours overlapping a monitoring period
+        if not _hour_overlaps_period(conn, row[0]):
+            continue
+
+        total_active += row[1]
+        total_idle += row[2]
+        total_powered_off += row[3]
+        total_unknown_from_hours += row[4]
+        total_bw += row[5]
+        total_br += row[6]
+        total_samples += row[7]
+        total_hour_wall_clock += row[1] + row[2] + row[3] + row[4]
+
+    # Wall-clock seconds inside monitoring periods for this day
+    period_wc = _period_wall_clock_for_day(conn, day)
+
+    # Gap seconds = period wall-clock - sum of existing hour wall-clock
+    gap_seconds = max(0, period_wc - total_hour_wall_clock)
+
+    total_unknown = total_unknown_from_hours + gap_seconds
+
+    # Coverage: known seconds / period wall-clock (§5.2, §5.3)
+    known_seconds = total_active + total_idle + total_powered_off
+    coverage = known_seconds / period_wc if period_wc > 0 else 0.0
+
+    return DayAggregate(
+        day=day,
+        seconds_active=total_active,
+        seconds_idle=total_idle,
+        seconds_powered_off=total_powered_off,
+        seconds_unknown=total_unknown,
+        bytes_written_delta=total_bw,
+        bytes_read_delta=total_br,
+        sample_count=total_samples,
+        coverage=coverage,
+    )
+
+
+def derive_all_days(conn: sqlite3.Connection) -> list[DayAggregate]:
+    """Derive day aggregates for all days that have hour rows.
+
+    Returns days sorted by date.
+    """
+    cursor = conn.execute(
+        "SELECT DISTINCT substr(hour, 1, 10) as day FROM hour_observations ORDER BY day"
+    )
+    days = [row[0] for row in cursor.fetchall()]
+
+    results = []
+    for day in days:
+        agg = derive_day(conn, day)
+        if agg is not None:
+            results.append(agg)
+    return results

src/fenris/derive.py

@@ -0,0 +1,237 @@
+"""Interval derivation: samples → hour observations → day aggregates.
+
+After each collection run, the collector calls into this module to:
+1. Find the previous sample in the same segment
+2. Compute deltas (bytes, POH, temperature)
+3. Classify the hour(s) the interval spans
+4. Write/update hour_observations for each affected hour
+5. Update day_aggregates with unattributed cross-hour bytes
+
+Cross-hour deltas are retained once with unknown shares explicit (issue #73 AC4).
+No proportional allocation, endpoint assignment, or double counting.
+"""
+import sqlite3
+from datetime import datetime, timedelta, timezone
+from typing import Any, Dict, List, Optional, Tuple
+
+from .hour_classify import classify_hour, HourSplit
+
+
+def find_previous_sample(
+    conn: sqlite3.Connection,
+    segment_id: Optional[int],
+    current_sample_id: int,
+) -> Optional[Dict[str, Any]]:
+    """Find the most recent sample before current_sample_id in the same segment.
+
+    Returns None if no previous sample exists (first sample in segment).
+    """
+    if segment_id is not None:
+        cursor = conn.execute(
+            "SELECT id, ts, bytes_written, bytes_read, power_on_hours, "
+            "       temperature_c, data_units_written, data_units_read "
+            "FROM samples WHERE id < ? AND segment_id = ? "
+            "ORDER BY id DESC LIMIT 1",
+            (current_sample_id, segment_id),
+        )
+    else:
+        cursor = conn.execute(
+            "SELECT id, ts, bytes_written, bytes_read, power_on_hours, "
+            "       temperature_c, data_units_written, data_units_read "
+            "FROM samples WHERE id < ? "
+            "ORDER BY id DESC LIMIT 1",
+            (current_sample_id,),
+        )
+    row = cursor.fetchone()
+    if row is None:
+        return None
+    return {
+        "id": row[0], "ts": row[1], "bytes_written": row[2],
+        "bytes_read": row[3], "power_on_hours": row[4],
+        "temperature_c": row[5], "data_units_written": row[6],
+        "data_units_read": row[7],
+    }
+
+
+def _parse_ts(ts: str) -> datetime:
+    """Parse ISO timestamp to datetime with UTC."""
+    dt = datetime.fromisoformat(ts)
+    if dt.tzinfo is None:
+        dt = dt.replace(tzinfo=timezone.utc)
+    return dt
+
+
+def _hour_floor(dt: datetime) -> datetime:
+    """Floor a datetime to its UTC hour boundary."""
+    return dt.replace(minute=0, second=0, microsecond=0)
+
+
+def _hours_spanned(start: datetime, end: datetime) -> List[datetime]:
+    """Return list of UTC hour boundaries spanned by [start, end)."""
+    hours = []
+    h = _hour_floor(start)
+    while h < end:
+        hours.append(h)
+        h += timedelta(hours=1)
+    return hours
+
+
+def _compute_sampled_seconds_in_hour(
+    start: datetime, end: datetime, hour_start: datetime
+) -> int:
+    """How many seconds of the sample interval fall within this hour."""
+    hour_end = hour_start + timedelta(hours=1)
+    effective_start = max(start, hour_start)
+    effective_end = min(end, hour_end)
+    if effective_start >= effective_end:
+        return 0
+    return int((effective_end - effective_start).total_seconds())
+
+
+def derive_hours_from_interval(
+    conn: sqlite3.Connection,
+    prev_sample: Dict[str, Any],
+    next_sample: Dict[str, Any],
+) -> List[Dict[str, Any]]:
+    """Derive hour observations from a sample pair interval.
+
+    Returns list of hour observation dicts that were written/updated.
+    """
+    prev_ts = _parse_ts(prev_sample["ts"])
+    next_ts = _parse_ts(next_sample["ts"])
+
+    # Deltas
+    bw_delta = max(0, next_sample["bytes_written"] - prev_sample["bytes_written"])
+    br_delta = max(0, next_sample["bytes_read"] - prev_sample["bytes_read"])
+    poh_delta_s = max(0, (next_sample["power_on_hours"] - prev_sample["power_on_hours"])) * 3600
+
+    hours = _hours_spanned(prev_ts, next_ts)
+    total_span_s = int((next_ts - prev_ts).total_seconds())
+
+    results = []
+
+    if len(hours) == 1:
+        # Same-hour interval: fully attributed to this hour
+        hour_key = hours[0].strftime("%Y-%m-%dT%H:00:00+00:00")
+        sampled_s = total_span_s
+
+        # Classify hour
+        split = classify_hour(
+            wall_clock_seconds=3600,
+            poh_delta=poh_delta_s,
+            duw_delta=bw_delta,
+            dur_delta=br_delta,
+            sampled_seconds=sampled_s,
+        )
+
+        _upsert_hour_observation(
+            conn, hour_key, split,
+            bw_delta, br_delta,
+            prev_sample.get("temperature_c"), next_sample.get("temperature_c"),
+            2,  # 2 samples contributed (prev + next)
+        )
+        results.append({"hour": hour_key, "bytes_written": bw_delta, "attributed": True})
+
+    elif len(hours) >= 2:
+        # Cross-hour interval: split wall-clock time, bytes unattributed
+        for h in hours:
+            hour_key = h.strftime("%Y-%m-%dT%H:00:00+00:00")
+            sampled_s = _compute_sampled_seconds_in_hour(prev_ts, next_ts, h)
+
+            # For cross-hour, we classify based on time only (no byte attribution)
+            # The hour gets its time split but NOT the byte delta
+            split = classify_hour(
+                wall_clock_seconds=3600,
+                poh_delta=0,  # POH attribution unknown for cross-hour
+                duw_delta=0,  # Bytes unattributed
+                dur_delta=0,
+                sampled_seconds=sampled_s,
+            )
+
+            _upsert_hour_observation(
+                conn, hour_key, split,
+                0, 0,  # No byte attribution for cross-hour
+                None, None,
+                0,  # No sample falls IN this hour
+            )
+            results.append({"hour": hour_key, "bytes_written": 0, "attributed": False})
+
+        # Track unattributed bytes at day level
+        _add_unattributed_bytes(conn, prev_ts, next_ts, bw_delta, br_delta)
+
+    return results
+
+
+def _upsert_hour_observation(
+    conn: sqlite3.Connection,
+    hour_key: str,
+    split: HourSplit,
+    bw_delta: int,
+    br_delta: int,
+    temp_min: Optional[int],
+    temp_max: Optional[int],
+    sample_count: int,
+) -> None:
+    """Insert or update an hour observation."""
+    # Check if hour exists
+    existing = conn.execute(
+        "SELECT id, bytes_written_delta, sample_count FROM hour_observations WHERE hour = ?",
+        (hour_key,),
+    ).fetchone()
+
+    if existing is None:
+        temp_avg = ((temp_min or 0) + (temp_max or 0)) / 2 if temp_min is not None else None
+        coverage = (split.seconds_active + split.seconds_idle + split.seconds_powered_off) / 3600.0
+        conn.execute(
+            """INSERT INTO hour_observations
+               (hour, active_seconds, idle_seconds, powered_off_seconds, unknown_seconds,
+                bytes_written_delta, bytes_read_delta,
+                temperature_min, temperature_avg, temperature_max,
+                sample_count, coverage)
+               VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)""",
+            (hour_key, split.seconds_active, split.seconds_idle,
+             split.seconds_powered_off, split.seconds_unknown,
+             bw_delta, br_delta,
+             temp_min, temp_avg, temp_max,
+             sample_count, coverage),
+        )
+    else:
+        # Merge: accumulate bytes and sample count
+        new_bw = existing[1] + bw_delta
+        new_samples = existing[2] + sample_count
+        conn.execute(
+            "UPDATE hour_observations SET bytes_written_delta = ?, sample_count = ? WHERE id = ?",
+            (new_bw, new_samples, existing[0]),
+        )
+    conn.commit()
+
+
+def _add_unattributed_bytes(
+    conn: sqlite3.Connection,
+    prev_ts: datetime,
+    next_ts: datetime,
+    bw_delta: int,
+    br_delta: int,
+) -> None:
+    """Add unattributed byte deltas to day aggregates for each day touched."""
+    prev_day = prev_ts.strftime("%Y-%m-%d")
+    next_day = next_ts.strftime("%Y-%m-%d")
+
+    days = {prev_day, next_day}
+    for day in days:
+        existing = conn.execute(
+            "SELECT id FROM day_aggregates WHERE day = ?", (day,)
+        ).fetchone()
+        if existing is None:
+            conn.execute(
+                "INSERT INTO day_aggregates (day, unattributed_bytes_written, unattributed_bytes_read) "
+                "VALUES (?, ?, ?)",
+                (day, bw_delta, br_delta),
+            )
+        else:
+            conn.execute(
+                "UPDATE day_aggregates SET unattributed_bytes_written = unattributed_bytes_written + ?, "
+                "unattributed_bytes_read = unattributed_bytes_read + ? WHERE day = ?",
+                (bw_delta, br_delta, day),
+            )
+    conn.commit()

src/fenris/hour_classify.py

@@ -0,0 +1,94 @@
+"""Hour classification per spec §5.1.
+
+Each UTC hour is classified by named constants, in this order of evidence:
+- Powered-off: power-on-hours delta < 90% of wall-clock span
+- Active: DUW delta >= 256 MiB in the hour
+- Idle: powered on, sampled, below active threshold
+- Unknown: everything else (unsampled without POH evidence)
+
+Four splits sum to exactly wall_clock_seconds. Disabled time is never an
+hour state — it is wall-clock outside monitoring periods (§5.2).
+"""
+from dataclasses import dataclass
+
+# Spec §5.1: Active hour threshold — 256 MiB DUW delta
+ACTIVE_THRESHOLD_BYTES = 256 * 1024 * 1024  # 256 MiB
+
+# Spec §5.1: Powered-off threshold — 90% of wall-clock span
+POWERED_OFF_THRESHOLD_PERCENT = 0.90
+
+
+@dataclass(frozen=True)
+class HourSplit:
+    """Usage-habit split for one UTC hour.  Fields sum to wall_clock_seconds."""
+    seconds_active: int
+    seconds_idle: int
+    seconds_powered_off: int
+    seconds_unknown: int
+
+
+def classify_hour(
+    wall_clock_seconds: int,
+    poh_delta: int,
+    duw_delta: int,
+    dur_delta: int,
+    sampled_seconds: int | None = None,
+) -> HourSplit:
+    """Classify a UTC hour into the four usage-habit states.
+
+    Args:
+        wall_clock_seconds: Total seconds in this hour boundary (3600 for a
+            full hour, less for partial-hours at period edges).
+        poh_delta: Power-on-hours delta since previous sample (in seconds).
+        duw_delta: Data-units-written delta since previous sample (in bytes).
+        dur_delta: Data-units-read delta since previous sample (in bytes).
+        sampled_seconds: Seconds within this hour covered by a sample.
+            None or 0 means no sample fell in this hour.
+
+    Returns:
+        HourSplit whose four fields sum to wall_clock_seconds.
+    """
+    if sampled_seconds is None:
+        sampled_seconds = 0
+
+    # Clamp sampled_seconds to wall_clock_seconds
+    sampled_seconds = min(sampled_seconds, wall_clock_seconds)
+
+    # --- Decision order per spec §5.1 ---
+
+    # 1. Powered-off: POH delta < 90% of wall-clock span
+    powered_off_threshold = wall_clock_seconds * POWERED_OFF_THRESHOLD_PERCENT
+    if poh_delta < powered_off_threshold:
+        return HourSplit(
+            seconds_active=0,
+            seconds_idle=0,
+            seconds_powered_off=wall_clock_seconds,
+            seconds_unknown=0,
+        )
+
+    # 2. Active: DUW delta >= 256 MiB
+    if duw_delta >= ACTIVE_THRESHOLD_BYTES:
+        return HourSplit(
+            seconds_active=wall_clock_seconds,
+            seconds_idle=0,
+            seconds_powered_off=0,
+            seconds_unknown=0,
+        )
+
+    # 3. Idle: powered on, sampled, below active threshold
+    #    Unsampled portion within the hour is unknown
+    if sampled_seconds > 0:
+        return HourSplit(
+            seconds_active=0,
+            seconds_idle=sampled_seconds,
+            seconds_powered_off=0,
+            seconds_unknown=wall_clock_seconds - sampled_seconds,
+        )
+
+    # 4. Unknown: unsampled without POH evidence
+    return HourSplit(
+        seconds_active=0,
+        seconds_idle=0,
+        seconds_powered_off=0,
+        seconds_unknown=wall_clock_seconds,
+    )

src/fenris/init_system.py

@@ -0,0 +1,479 @@
+"""Init system abstraction for Fenris monitoring (issue #84).
+
+Detects the active init system (systemd or runit) and provides a unified
+interface for timer/collection control and service-state queries.  This keeps
+the privileged helper and status composition init-system agnostic without
+introducing a generalized plugin framework.
+
+Design: ADR 0008 — keep service-specific operations behind a cohesive
+responsibility shared by the privileged control path and read-only status
+composition.
+
+Runit service layout:
+  /etc/sv/fenris-collect/run        — scheduler (sleep 120; loop { collect; sleep 300 })
+  /etc/sv/fenris-collect/log/run    — logger to /var/log/fenris-collect/
+  /var/service/fenris-collect       — symlink to enable
+  /etc/sv/fenris-collect/down       — marker for dormant install
+
+Runit guarantees:
+  - Completion-relative 5-minute cadence (sleep 300 after each collect)
+  - Initial 2-minute boot delay (sleep 120 before first collect)
+  - Bounded execution (90s timeout via timeout(1))
+  - No catch-up (service sleeps fixed interval, no Persistent= flag)
+  - Serialized scheduled runs (runsv does not restart until exit)
+  - Serialized on-demand (flock serializes fenris-collect execution)
+
+Spec: §8.4, §8.5, §8.6, §8.7, §8.8, ADR 0008
+"""
+import os
+import shutil
+import subprocess
+import sys
+from enum import Enum
+from pathlib import Path
+from typing import Any, Dict, Optional
+
+
+# ---------------------------------------------------------------------------
+# Init system detection
+# ---------------------------------------------------------------------------
+
+class InitSystem(Enum):
+    SYSTEMD = "systemd"
+    RUNIT = "runit"
+
+
+FENRIS_SV_DIR = Path("/etc/sv/fenris-collect")
+FENRIS_SERVICE_LINK = Path("/var/service/fenris-collect")
+FENRIS_LOG_DIR = Path("/var/log/fenris-collect")
+COLLECT_TIMEOUT_S = 90
+
+
+def detect_init_system() -> InitSystem:
+    """Detect the active init system.
+
+    Checks for systemd first (PID 1 is systemd or /run/systemd/system exists),
+    then falls back to runit (PID 1 is runsv or /etc/sv exists).
+    """
+    # systemd detection: /run/systemd/system exists when systemd is PID 1
+    if Path("/run/systemd/system").exists():
+        return InitSystem.SYSTEMD
+
+    # Check PID 1 name
+    try:
+        pid1_comm = Path("/proc/1/comm").read_text().strip()
+        if pid1_comm == "systemd":
+            return InitSystem.SYSTEMD
+        if pid1_comm in ("runsv", "runsvdir"):
+            return InitSystem.RUNIT
+    except OSError:
+        pass
+
+    # Fallback: check for /etc/sv (Void Linux default)
+    if Path("/etc/sv").is_dir():
+        return InitSystem.RUNIT
+
+    # Default to systemd (existing behavior)
+    return InitSystem.SYSTEMD
+
+
+def get_init_system() -> InitSystem:
+    """Get the detected init system (cached)."""
+    if not hasattr(get_init_system, "_cached"):
+        get_init_system._cached = detect_init_system()
+    return get_init_system._cached
+
+
+def reset_init_system_cache() -> None:
+    """Reset the cached init system detection (for testing)."""
+    if hasattr(get_init_system, "_cached"):
+        delattr(get_init_system, "_cached")
+
+
+# ---------------------------------------------------------------------------
+# systemd backend
+# ---------------------------------------------------------------------------
+
+def _systemd_enable(now: bool) -> None:
+    """Enable and optionally start the systemd timer."""
+    cmd = ["systemctl", "enable"]
+    if now:
+        cmd.append("--now")
+    cmd.append("fenris-collect.timer")
+    result = subprocess.run(cmd, capture_output=True, text=True)
+    if result.returncode != 0:
+        print("Error enabling timer:", result.stderr, file=sys.stderr)
+        sys.exit(1)
+    print("Timer enabled" + (" and started" if now else ""))
+
+
+def _systemd_disable(now: bool) -> None:
+    """Disable and optionally stop the systemd timer."""
+    cmd = ["systemctl", "disable"]
+    if now:
+        cmd.append("--now")
+    cmd.append("fenris-collect.timer")
+    result = subprocess.run(cmd, capture_output=True, text=True)
+    if result.returncode != 0:
+        print("Error disabling timer:", result.stderr, file=sys.stderr)
+        sys.exit(1)
+    print("Timer disabled" + (" and stopped" if now else ""))
+
+
+def _systemd_collect() -> None:
+    """Trigger on-demand collection via systemd (blocking)."""
+    result = subprocess.run(
+        ["systemctl", "start", "fenris-collect.service"],
+        capture_output=True,
+        text=True,
+    )
+    if result.returncode == 0:
+        print("Collection completed successfully")
+    else:
+        print("Collection failed:", result.stderr, file=sys.stderr)
+        sys.exit(1)
+
+
+def _systemctl_show(unit: str, *properties: str) -> Dict[str, str]:
+    """Query systemctl show for specific properties."""
+    try:
+        result = subprocess.run(
+            ["systemctl", "show", unit, "--property=" + ",".join(properties)],
+            capture_output=True, text=True, timeout=5,
+        )
+        if result.returncode != 0:
+            return {}
+        out = {}
+        for line in result.stdout.splitlines():
+            if "=" in line:
+                key, _, value = line.partition("=")
+                out[key.strip()] = value.strip()
+        return out
+    except (subprocess.TimeoutExpired, FileNotFoundError, OSError):
+        return {}
+
+
+def _systemd_query_state() -> Dict[str, Any]:
+    """Query systemd for the four separate service facts."""
+    from datetime import datetime, timezone
+
+    timer_props = _systemctl_show(
+        "fenris-collect.timer",
+        "UnitFileState", "ActiveState", "LastTriggerUSec",
+    )
+    service_props = _systemctl_show(
+        "fenris-collect.service",
+        "ActiveState", "ExecMainStatus", "ExecMainExitTimestamp",
+    )
+
+    boot_enabled_str = timer_props.get("UnitFileState", "")
+    boot_enabled = boot_enabled_str == "enabled"
+
+    active_state = timer_props.get("ActiveState", "inactive")
+    timer_active = active_state == "active"
+
+    last_collect_ok = None
+    last_collect_age_s = None
+    last_collect_reason = None
+
+    last_trigger = timer_props.get("LastTriggerUSec", "")
+    if last_trigger and last_trigger != "n/a":
+        try:
+            trigger_dt = datetime.fromisoformat(last_trigger.replace("Z", "+00:00"))
+            now = datetime.now(timezone.utc)
+            last_collect_age_s = int((now - trigger_dt).total_seconds())
+        except (ValueError, TypeError):
+            pass
+
+    exec_status = service_props.get("ExecMainStatus", "")
+    if exec_status:
+        try:
+            exit_code = int(exec_status)
+            last_collect_ok = exit_code == 0
+            if exit_code != 0:
+                last_collect_reason = "exit code %d" % exit_code
+        except (ValueError, TypeError):
+            pass
+
+    return {
+        "boot_enabled": boot_enabled,
+        "timer_active": timer_active,
+        "last_collect_ok": last_collect_ok,
+        "last_collect_age_s": last_collect_age_s,
+        "last_collect_reason": last_collect_reason,
+    }
+
+
+def _systemd_journal_hint(lines: int = 5) -> Optional[str]:
+    """Get the last N journal lines for fenris-collect.service."""
+    try:
+        result = subprocess.run(
+            ["journalctl", "-u", "fenris-collect.service",
+             "--no-pager", "-n", str(lines), "--output=short-iso"],
+            capture_output=True, text=True, timeout=5,
+        )
+        if result.returncode != 0 or not result.stdout.strip():
+            return None
+        return result.stdout.strip()
+    except (subprocess.TimeoutExpired, FileNotFoundError, OSError):
+        return None
+
+
+# ---------------------------------------------------------------------------
+# runit backend
+# ---------------------------------------------------------------------------
+
+def _runit_enable(_now: bool) -> None:
+    """Enable the runit service by creating a symlink.
+
+    runit activates the service immediately when the symlink appears.
+    If the service is already enabled but stopped (e.g., via `sv stop`),
+    restart it when `now=True`.
+    """
+    if FENRIS_SERVICE_LINK.exists():
+        # Already enabled — check if we need to restart
+        if _now and not _runit_is_running():
+            # Service is stopped but enabled — restart via sv
+            try:
+                subprocess.run(
+                    ["sv", "restart", "fenris-collect"],
+                    capture_output=True, text=True, timeout=5,
+                )
+            except (FileNotFoundError, subprocess.TimeoutExpired):
+                pass
+        print("Service already enabled (idempotent)")
+        return
+
+    # Remove the 'down' file if present (dormant install marker)
+    down_file = FENRIS_SV_DIR / "down"
+    if down_file.exists():
+        down_file.unlink()
+
+    FENRIS_SERVICE_LINK.symlink_to(FENRIS_SV_DIR)
+    print("Service enabled")
+
+
+def _runit_disable(_now: bool) -> None:
+    """Disable the runit service by removing the symlink.
+
+    runit stops the service immediately when the symlink is removed.
+    """
+    if not FENRIS_SERVICE_LINK.exists():
+        print("Service already disabled (idempotent)")
+        return
+
+    FENRIS_SERVICE_LINK.unlink()
+    # Place 'down' file to mark as intentionally disabled
+    (FENRIS_SV_DIR / "down").touch()
+    print("Service disabled")
+
+
+def _runit_collect() -> None:
+    """Trigger on-demand collection via direct execution with flock.
+
+    Serializes against the scheduler using the same lock file.
+    The timeout(1) command enforces bounded execution.
+    """
+    lock_path = Path("/var/lib/fenris/fenris-collect.lock")
+    collect_script = Path("/usr/libexec/fenris/fenris-collect")
+    fallback_script = Path(__file__).parent.parent.parent / "src" / "fenris" / "collect.py"
+
+    if collect_script.exists():
+        script = str(collect_script)
+    elif fallback_script.exists():
+        script = str(fallback_script)
+    else:
+        print("Error: fenris-collect script not found", file=sys.stderr)
+        sys.exit(1)
+
+    try:
+        result = subprocess.run(
+            ["flock", "--nonblock", str(lock_path),
+             "timeout", str(COLLECT_TIMEOUT_S), "nice", "ionice", "-c3",
+             sys.executable, script],
+            capture_output=True,
+            text=True,
+        )
+        if result.returncode == 0:
+            print("Collection completed successfully")
+        elif result.returncode == 124:
+            print("Collection timed out after %ds" % COLLECT_TIMEOUT_S, file=sys.stderr)
+            sys.exit(1)
+        else:
+            # exit code 1 from flock means lock is held (scheduled run in progress)
+            if result.returncode == 1 and "Resource temporarily unavailable" in result.stderr:
+                print("Collection already in progress (serialized)", file=sys.stderr)
+                sys.exit(1)
+            print("Collection failed:", result.stderr, file=sys.stderr)
+            sys.exit(1)
+    except FileNotFoundError:
+        print("Error: flock/timeout not found", file=sys.stderr)
+        sys.exit(1)
+
+
+def _runit_is_enabled() -> bool:
+    """Check if the runit service is enabled (symlink exists)."""
+    return FENRIS_SERVICE_LINK.exists()
+
+
+def _runit_is_running() -> bool:
+    """Check if the runit service is currently running.
+
+    Looks for a 'supervise/pid' file in the service directory.
+    """
+    pid_file = FENRIS_SV_DIR / "supervise" / "pid"
+    if not pid_file.exists():
+        return False
+    try:
+        pid = int(pid_file.read_text().strip())
+        # Check if the process is alive
+        os.kill(pid, 0)
+        return True
+    except (ValueError, OSError):
+        return False
+
+
+def _runit_query_state() -> Dict[str, Any]:
+    """Query runit for the four separate service facts.
+
+    Checks: boot_enabled (symlink), timer_active (running), last_collect
+    (store-based), freshness (store-based).
+    """
+    from datetime import datetime, timezone
+    from pathlib import Path
+
+    boot_enabled = _runit_is_enabled()
+    timer_active = _runit_is_running()
+
+    last_collect_ok = None
+    last_collect_age_s = None
+    last_collect_reason = None
+
+    # Try to get last collection info from the store
+    store_path = Path("/var/lib/fenris/observations.db")
+    if store_path.exists():
+        try:
+            import sqlite3
+            conn = sqlite3.connect("file:%s?mode=ro" % store_path, uri=True)
+            conn.row_factory = sqlite3.Row
+
+            # Get newest sample
+            cursor = conn.execute(
+                "SELECT ts FROM samples ORDER BY id DESC LIMIT 1"
+            )
+            row = cursor.fetchone()
+            if row and row[0]:
+                try:
+                    ts = datetime.fromisoformat(row[0])
+                    if ts.tzinfo is None:
+                        ts = ts.replace(tzinfo=timezone.utc)
+                    now = datetime.now(timezone.utc)
+                    last_collect_age_s = int((now - ts).total_seconds())
+                    last_collect_ok = True
+                except (ValueError, TypeError):
+                    pass
+
+            # Check for failed collections via monitoring_periods
+            cursor = conn.execute(
+                "SELECT end_cause FROM monitoring_periods "
+                "WHERE ended_at IS NOT NULL ORDER BY ended_at DESC LIMIT 1"
+            )
+            row = cursor.fetchone()
+            if row and row[0] and row[0] not in ("user_disabled", None):
+                last_collect_reason = row[0]
+
+            conn.close()
+        except Exception:
+            pass
+
+    # Check for timeout/exit failures via supervise exit status
+    if timer_active:
+        exit_file = FENRIS_SV_DIR / "supervise" / "exit"
+        if exit_file.exists():
+            try:
+                exit_code = int(exit_file.read_text().strip())
+                if exit_code != 0:
+                    last_collect_ok = False
+                    last_collect_reason = "exit code %d" % exit_code
+            except (ValueError, OSError):
+                pass
+
+    return {
+        "boot_enabled": boot_enabled,
+        "timer_active": timer_active,
+        "last_collect_ok": last_collect_ok,
+        "last_collect_age_s": last_collect_age_s,
+        "last_collect_reason": last_collect_reason,
+    }
+
+
+def _runit_journal_hint(lines: int = 5) -> Optional[str]:
+    """Get the last N log lines for fenris-collect from runit logging."""
+    log_current = FENRIS_LOG_DIR / "current"
+    if not log_current.exists():
+        return None
+    try:
+        # Use tail to get the last N lines
+        result = subprocess.run(
+            ["tail", "-n", str(lines), str(log_current)],
+            capture_output=True, text=True, timeout=5,
+        )
+        if result.returncode != 0 or not result.stdout.strip():
+            return None
+        return result.stdout.strip()
+    except (subprocess.TimeoutExpired, FileNotFoundError, OSError):
+        return None
+
+
+# ---------------------------------------------------------------------------
+# Public API — unified interface
+# ---------------------------------------------------------------------------
+
+def enable_timer(now: bool) -> None:
+    """Enable the collection timer/service."""
+    init = get_init_system()
+    if init == InitSystem.SYSTEMD:
+        _systemd_enable(now)
+    else:
+        _runit_enable(now)
+
+
+def disable_timer(now: bool) -> None:
+    """Disable the collection timer/service."""
+    init = get_init_system()
+    if init == InitSystem.SYSTEMD:
+        _systemd_disable(now)
+    else:
+        _runit_disable(now)
+
+
+def collect_now() -> None:
+    """Trigger on-demand collection (blocking)."""
+    init = get_init_system()
+    if init == InitSystem.SYSTEMD:
+        _systemd_collect()
+    else:
+        _runit_collect()
+
+
+def query_service_state() -> Dict[str, Any]:
+    """Query the four separate service facts."""
+    init = get_init_system()
+    if init == InitSystem.SYSTEMD:
+        return _systemd_query_state()
+    else:
+        return _runit_query_state()
+
+
+def journal_hint(lines: int = 5, unit: str = "fenris-collect.service") -> Optional[str]:
+    """Get journal/log hints for diagnostics.
+
+    The unit parameter is accepted for backward compatibility with callers
+    that pass 'fenris-collect.service'.  For runit, the unit parameter is
+    ignored since the log directory is always /var/log/fenris-collect/.
+    """
+    init = get_init_system()
+    if init == InitSystem.SYSTEMD:
+        return _systemd_journal_hint(lines)
+    else:
+        return _runit_journal_hint(lines)

src/fenris/legacy.py

@@ -0,0 +1,440 @@
+"""Legacy migration: import history.jsonl into the observation store.
+
+Spec §3.5, ADR 0001 §6. Idempotent and interruption-safe.
+
+Entry points:
+- Installer import detection at ./data/history.jsonl (§10.1)
+- fenris import <path> (§8.8)
+- Collector's first new-version run (ADR 0001 §6)
+
+The import is a single transaction — a scripted kill mid-import leaves the
+store fully pre- or fully post-migration. history.jsonl is the sole authority;
+hourly.jsonl is diffed and logged but never trusted. Malformed lines are
+quarantined with a logged count, never silently dropped. Legacy files are
+renamed *.migrated only after commit and never deleted.
+"""
+import json
+import logging
+import sqlite3
+from datetime import datetime, timezone
+from pathlib import Path
+from typing import Any, Dict, List, Optional, Tuple
+
+from .hour_classify import classify_hour
+from .segment import open_segment, normalize_identity
+from .monitoring_periods import close_period
+
+logger = logging.getLogger(__name__)
+
+# Legacy import marker — stored in a metadata table
+LEGACY_IMPORT_MARKER = "legacy_imported"
+
+
+def _ensure_metadata_table(conn: sqlite3.Connection) -> None:
+    """Create the metadata table if it doesn't exist."""
+    conn.execute("""
+        CREATE TABLE IF NOT EXISTS store_metadata (
+            key TEXT PRIMARY KEY,
+            value TEXT NOT NULL
+        )
+    """)
+
+
+def is_legacy_imported(conn: sqlite3.Connection) -> bool:
+    """Check if legacy history has already been imported.
+    
+    Spec §3.5.1: If the store already carries the legacy-import marker, do nothing.
+    """
+    _ensure_metadata_table(conn)
+    cursor = conn.execute(
+        "SELECT value FROM store_metadata WHERE key = ?",
+        (LEGACY_IMPORT_MARKER,),
+    )
+    row = cursor.fetchone()
+    return row is not None and row[0] == "true"
+
+
+def _parse_history_line(line: str, line_num: int) -> Optional[Dict[str, Any]]:
+    """Parse a single line from history.jsonl.
+    
+    Returns None for malformed lines (quarantined, not silently dropped).
+    """
+    line = line.strip()
+    if not line:
+        return None
+    
+    try:
+        record = json.loads(line)
+    except json.JSONDecodeError as e:
+        logger.warning("Malformed JSON at line %d: %s", line_num, e)
+        return None
+    
+    # Validate required fields
+    required_fields = [
+        "timestamp", "model", "serial", "firmware_version",
+        "data_units_written", "data_units_read", "percentage_used",
+        "power_on_hours", "temperature",
+    ]
+    
+    for field in required_fields:
+        if field not in record:
+            logger.warning("Missing field '%s' at line %d", field, line_num)
+            return None
+    
+    return record
+
+
+def _record_to_sample(record: Dict[str, Any]) -> Dict[str, Any]:
+    """Convert a legacy history.jsonl record to a sample dict."""
+    # Legacy records use different field names
+    duw = record["data_units_written"]
+    dur = record["data_units_read"]
+    
+    return {
+        "ts": record["timestamp"],
+        "device": record.get("device", "/dev/nvme0"),
+        "subnqn": record.get("subsystem_nqn", ""),
+        "sn": record["serial"],
+        "mn": record["model"],
+        "fr": record["firmware_version"],
+        "capacity_bytes": record.get("capacity_bytes", 0),
+        "percentage_used": record["percentage_used"],
+        "available_spare": record.get("available_spare"),
+        "media_errors": record.get("media_errors", 0),
+        "power_on_hours": record["power_on_hours"],
+        "power_cycles": record.get("power_cycles"),
+        "unsafe_shutdowns": record.get("unsafe_shutdowns"),
+        "temperature_c": record["temperature"],
+        "data_units_written": duw,
+        "data_units_read": dur,
+        "bytes_written": duw * 512000,
+        "bytes_read": dur * 512000,
+        "critical_warning": record.get("critical_warning", 0),
+    }
+
+
+def _derive_hour_observation(
+    samples: List[Dict[str, Any]],
+    hour_start: datetime,
+) -> Dict[str, Any]:
+    """Derive a single hour observation from samples in that hour.
+    
+    Pre-migration hours carry an unknown activity split except directly
+    evidenced facts — a sample present means powered on; a DUW delta means
+    writes occurred (§3.5.4).
+    """
+    hour_end = hour_start.replace(hour=hour_start.hour + 1) if hour_start.hour < 23 else                hour_start.replace(hour=0, day=hour_start.day + 1)
+    
+    # Filter samples in this hour
+    hour_samples = []
+    for s in samples:
+        ts = datetime.fromisoformat(s["ts"])
+        if hour_start <= ts < hour_end:
+            hour_samples.append(s)
+    
+    if not hour_samples:
+        return None
+    
+    # Sort by timestamp
+    hour_samples.sort(key=lambda x: x["ts"])
+    
+    # Compute deltas from first to last sample in the hour
+    first = hour_samples[0]
+    last = hour_samples[-1]
+    
+    duw_delta = last["bytes_written"] - first["bytes_written"]
+    dur_delta = last["bytes_read"] - first["bytes_read"]
+    poh_delta = (last["power_on_hours"] - first["power_on_hours"]) * 3600
+    
+    # Temperature stats
+    temps = [s["temperature_c"] for s in hour_samples]
+    
+    # Classify the hour
+    split = classify_hour(
+        wall_clock_seconds=3600,
+        poh_delta=poh_delta,
+        duw_delta=duw_delta,
+        dur_delta=dur_delta,
+        sampled_seconds=3600,  # Legacy samples cover the full hour
+    )
+    
+    return {
+        "hour": hour_start.strftime("%Y-%m-%dT%H:00:00Z"),
+        "active_seconds": split.seconds_active,
+        "idle_seconds": split.seconds_idle,
+        "powered_off_seconds": split.seconds_powered_off,
+        "unknown_seconds": split.seconds_unknown,
+        "bytes_written_delta": duw_delta,
+        "bytes_read_delta": dur_delta,
+        "temperature_min": min(temps),
+        "temperature_avg": sum(temps) / len(temps),
+        "temperature_max": max(temps),
+        "sample_count": len(hour_samples),
+        "coverage": 1.0 if split.seconds_unknown == 0 else (3600 - split.seconds_unknown) / 3600,
+    }
+
+
+def _diff_hourly_jsonl(
+    hourly_path: Path,
+    derived_hours: Dict[str, Dict[str, Any]],
+) -> None:
+    """Diff hourly.jsonl against derived data and log mismatches.
+    
+    Spec §3.5.3: hourly.jsonl is never trusted; mismatches are diffed and logged.
+    """
+    if not hourly_path.exists():
+        logger.info("No hourly.jsonl found for diffing")
+        return
+    
+    try:
+        with open(hourly_path, "r") as f:
+            for line_num, line in enumerate(f, 1):
+                line = line.strip()
+                if not line:
+                    continue
+                
+                try:
+                    record = json.loads(line)
+                except json.JSONDecodeError:
+                    logger.warning("Malformed hourly.jsonl at line %d", line_num)
+                    continue
+                
+                hour_key = record.get("hour")
+                if hour_key not in derived_hours:
+                    logger.info("Hourly.jsonl has hour %s not in derived data", hour_key)
+                    continue
+                
+                derived = derived_hours[hour_key]
+                mismatches = []
+                
+                for field in ["bytes_written_delta", "bytes_read_delta", "sample_count"]:
+                    if field in record and record[field] != derived.get(field):
+                        mismatches.append(
+                            f"{field}: hourly={record[field]} derived={derived.get(field)}"
+                        )
+                
+                if mismatches:
+                    logger.info(
+                        "Hourly.jsonl mismatch for %s: %s",
+                        hour_key,
+                        "; ".join(mismatches),
+                    )
+    except Exception as e:
+        logger.warning("Failed to diff hourly.jsonl: %s", e)
+
+
+def import_legacy_history(
+    conn: sqlite3.Connection,
+    history_path: Path,
+    hourly_path: Optional[Path] = None,
+    clock=None,
+) -> Dict[str, Any]:
+    """Import legacy history.jsonl into the observation store.
+    
+    This is the main entry point for legacy migration. It is:
+    - Idempotent: second run no-ops on the legacy-import marker
+    - Interruption-safe: single transaction
+    - Never creates synthetic baselines
+    
+    Args:
+        conn: Connection to the observation store
+        history_path: Path to history.jsonl
+        hourly_path: Optional path to hourly.jsonl for diffing
+        clock: Injected clock (for testing)
+    
+    Returns:
+        Dict with migration outcome
+    """
+    # Check idempotency
+    if is_legacy_imported(conn):
+        return {"ok": True, "skipped": True, "reason": "already_imported"}
+    
+    # Read and parse history.jsonl
+    samples = []
+    malformed_count = 0
+    
+    if not history_path.exists():
+        return {"ok": False, "error": f"History file not found: {history_path}"}
+    
+    with open(history_path, "r") as f:
+        for line_num, line in enumerate(f, 1):
+            record = _parse_history_line(line, line_num)
+            if record is None:
+                malformed_count += 1
+                continue
+            samples.append(_record_to_sample(record))
+    
+    if malformed_count > 0:
+        logger.warning("Quarantined %d malformed lines from history.jsonl", malformed_count)
+    
+    if not samples:
+        return {"ok": False, "error": "No valid samples found in history.jsonl"}
+    
+    # Sort samples by timestamp
+    samples.sort(key=lambda x: x["ts"])
+    
+    # Derive hour observations
+    hour_observations = {}
+    for sample in samples:
+        ts = datetime.fromisoformat(sample["ts"])
+        hour_start = ts.replace(minute=0, second=0, microsecond=0)
+        hour_key = hour_start.strftime("%Y-%m-%dT%H:00:00Z")
+        
+        if hour_key not in hour_observations:
+            hour_observations[hour_key] = {
+                "hour": hour_start,
+                "samples": [],
+            }
+        hour_observations[hour_key]["samples"].append(sample)
+    
+    derived_hours = {}
+    for hour_key, hour_data in hour_observations.items():
+        obs = _derive_hour_observation(hour_data["samples"], hour_data["hour"])
+        if obs is not None:
+            derived_hours[hour_key] = obs
+    
+    # Diff against hourly.jsonl if provided
+    if hourly_path:
+        _diff_hourly_jsonl(hourly_path, derived_hours)
+    
+    # Single transaction for the entire import
+    try:
+        # Begin transaction
+        conn.execute("BEGIN IMMEDIATE")
+        
+        # 1. Insert raw samples
+        for sample in samples:
+            conn.execute(
+                """
+                INSERT INTO samples (
+                    ts, device, subnqn, sn, mn, fr, capacity_bytes,
+                    percentage_used, available_spare, media_errors, power_on_hours,
+                    power_cycles, unsafe_shutdowns, temperature_c,
+                    data_units_written, data_units_read, bytes_written, bytes_read,
+                    critical_warning
+                ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+                """,
+                (
+                    sample["ts"],
+                    sample["device"],
+                    sample["subnqn"],
+                    sample["sn"],
+                    sample["mn"],
+                    sample["fr"],
+                    sample["capacity_bytes"],
+                    sample["percentage_used"],
+                    sample["available_spare"],
+                    sample["media_errors"],
+                    sample["power_on_hours"],
+                    sample["power_cycles"],
+                    sample["unsafe_shutdowns"],
+                    sample["temperature_c"],
+                    sample["data_units_written"],
+                    sample["data_units_read"],
+                    sample["bytes_written"],
+                    sample["bytes_read"],
+                    sample["critical_warning"],
+                ),
+            )
+        
+        # 2. Insert derived hour observations
+        for hour_key, obs in sorted(derived_hours.items()):
+            conn.execute(
+                """
+                INSERT OR REPLACE INTO hour_observations (
+                    hour, active_seconds, idle_seconds, powered_off_seconds,
+                    unknown_seconds, bytes_written_delta, bytes_read_delta,
+                    temperature_min, temperature_avg, temperature_max,
+                    sample_count, coverage
+                ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+                """,
+                (
+                    obs["hour"],
+                    obs["active_seconds"],
+                    obs["idle_seconds"],
+                    obs["powered_off_seconds"],
+                    obs["unknown_seconds"],
+                    obs["bytes_written_delta"],
+                    obs["bytes_read_delta"],
+                    obs["temperature_min"],
+                    obs["temperature_avg"],
+                    obs["temperature_max"],
+                    obs["sample_count"],
+                    obs["coverage"],
+                ),
+            )
+        
+        # 3. Open implicit monitoring period at first legacy sample
+        first_sample_ts = datetime.fromisoformat(samples[0]["ts"])
+        conn.execute(
+            "INSERT INTO monitoring_periods (started_at) VALUES (?)",
+            (first_sample_ts.isoformat(),),
+        )
+        
+        # 4. Close period with end_cause = migrated at migration moment
+        if clock:
+            migration_time = clock.utcnow()
+        else:
+            migration_time = datetime.now(timezone.utc)
+        
+        conn.execute(
+            "UPDATE monitoring_periods SET ended_at = ?, end_cause = ? WHERE ended_at IS NULL",
+            (migration_time.isoformat(), "migrated"),
+        )
+        
+        # 5. Open legacy controller segment (mn-only)
+        # Legacy identity is model-scoped only (§4.4)
+        first_sample = samples[0]
+        legacy_identity = {
+            "mn": first_sample["mn"],
+            "sn": "",  # Legacy segments are mn-only
+            "subnqn": "",
+            "fr": "",
+        }
+        legacy_identity_key = f"legacy|{first_sample['mn']}"
+        open_segment(
+            conn,
+            migration_time,
+            legacy_identity,
+            legacy_identity_key,
+            identity_degraded=False,
+        )
+        
+        # 6. Set legacy import marker
+        _ensure_metadata_table(conn)
+        conn.execute(
+            "INSERT OR REPLACE INTO store_metadata (key, value) VALUES (?, ?)",
+            (LEGACY_IMPORT_MARKER, "true"),
+        )
+        
+        # Commit
+        conn.commit()
+        
+    except Exception as e:
+        conn.rollback()
+        raise RuntimeError(f"Migration failed: {e}") from e
+    
+    # 7. Rename legacy files to *.migrated (only after commit)
+    try:
+        migrated_path = history_path.with_suffix(history_path.suffix + ".migrated")
+        history_path.rename(migrated_path)
+        logger.info("Renamed %s to %s", history_path, migrated_path)
+        
+        if hourly_path and hourly_path.exists():
+            hourly_migrated = hourly_path.with_suffix(hourly_path.suffix + ".migrated")
+            hourly_path.rename(hourly_migrated)
+            logger.info("Renamed %s to %s", hourly_path, hourly_migrated)
+    except Exception as e:
+        # Non-fatal: files weren't renamed but migration succeeded
+        logger.warning("Failed to rename legacy files: %s", e)
+    
+    return {
+        "ok": True,
+        "skipped": False,
+        "samples_imported": len(samples),
+        "hours_imported": len(derived_hours),
+        "malformed_lines": malformed_count,
+        "first_sample": samples[0]["ts"],
+        "last_sample": samples[-1]["ts"],
+        "legacy_identity_key": legacy_identity_key,
+    }

src/fenris/monitor.py

@@ -0,0 +1,242 @@
+#!/usr/bin/env python3
+"""fenris-monitor: privileged helper for toggle, collect, and baseline operations.
+
+This binary is the ONLY sanctioned control path for:
+- enable/disable (toggle) with monitoring-period bookkeeping
+- on-demand collection trigger
+- baseline set/clear persistence
+
+Polkit authorizes this binary under com.bongbetic.fenris.monitor (auth_admin).
+
+Spec: §8.4, §8.5, §8.6, §8.7
+
+When run as a script, uses the fenris package from the installed wheel.
+"""
+import argparse
+import json
+import os
+import sys
+from datetime import datetime, timezone
+from pathlib import Path
+
+# Package dependencies are vendored independently of the host Python minor
+# version.  Keep the venv fallback for the legacy development install.
+VENV_DIR = Path("/opt/fenris")
+if VENV_DIR.exists():
+    vendor_dir = VENV_DIR / "vendor"
+    if vendor_dir.is_dir():
+        sys.path.insert(0, str(vendor_dir))
+    else:
+        site_packages = next((VENV_DIR / "lib").glob("python*/site-packages"), None)
+        if site_packages:
+            sys.path.insert(0, str(site_packages))
+
+from fenris.store import init_store, get_store_path
+from fenris.monitoring_periods import (
+    ensure_period_open,
+    close_period,
+    get_open_period,
+)
+from fenris.init_system import (
+    enable_timer,
+    disable_timer,
+    collect_now,
+)
+
+
+DEFAULT_STORE_PATH = Path("/var/lib/fenris/observations.db")
+
+
+def is_root() -> bool:
+    """Check if running as root."""
+    return os.geteuid() == 0
+
+
+def cmd_enable(args: argparse.Namespace) -> None:
+    """Enable monitoring: enable timer + open monitoring period.
+
+    Idempotent matrix (§8.6):
+    - First-ever enable: opens a period at the enable moment
+    - Resume with open period: no-op (gap stays inside as unknown)
+    - Resume with no open period: opens a new row
+    """
+    store_path = getattr(args, 'store_path', DEFAULT_STORE_PATH)
+    conn = init_store(store_path)
+    now = datetime.now(timezone.utc)
+
+    try:
+        # Open monitoring period if none exists (§8.6)
+        open_period = get_open_period(conn)
+        if open_period is None:
+            ensure_period_open(conn, now)
+            print("Monitoring period opened at", now.isoformat())
+        else:
+            print("Monitoring period already open (id=%d)" % open_period["id"])
+
+        # Enable the timer (init-system aware)
+        enable_timer(args.now)
+    finally:
+        conn.close()
+
+
+def cmd_disable(args: argparse.Namespace) -> None:
+    """Disable monitoring: disable timer + close monitoring period.
+
+    Idempotent matrix (§8.6):
+    - Pause with open period: closes it user_disabled
+    - Pause otherwise: no-op
+    """
+    store_path = getattr(args, 'store_path', DEFAULT_STORE_PATH)
+    if not store_path.exists():
+        print("Error: Observation store not found at", store_path, file=sys.stderr)
+        sys.exit(1)
+
+    conn = init_store(store_path)
+    now = datetime.now(timezone.utc)
+
+    try:
+        # Close monitoring period if open (§8.6)
+        open_period = get_open_period(conn)
+        if open_period is not None:
+            close_period(conn, now, "user_disabled")
+            print("Monitoring period closed (id=%d)" % open_period["id"])
+        else:
+            print("No open monitoring period (no-op)")
+
+        # Disable the timer (init-system aware)
+        disable_timer(args.now)
+    finally:
+        conn.close()
+
+
+def cmd_collect(args: argparse.Namespace) -> None:
+    """Trigger on-demand collection.
+
+    Starts fenris-collect, blocks until exit, reports outcome.
+
+    Spec §8.7: fenris sample routes through fenris-monitor → collect,
+    which blocks until the collection exits; outcome reported synchronously.
+    """
+    collect_now()
+
+
+def cmd_baseline_set(args: argparse.Namespace) -> None:
+    """Persist a baseline row after CLI-side validation.
+
+    Spec §8.4: fenris-monitor persists CLI-validated baseline rows.
+    Spec PR-14: baseline set persists through polkit-guarded helper.
+    """
+    store_path = getattr(args, 'store_path', DEFAULT_STORE_PATH)
+    if not store_path.exists():
+        print("Error: Observation store not found at", store_path, file=sys.stderr)
+        sys.exit(1)
+
+    conn = init_store(store_path)
+    now = datetime.now(timezone.utc)
+
+    try:
+        # Parse and validate baseline data
+        data = json.loads(args.baseline_json)
+
+        required_fields = [
+            "tbw_terabytes",
+            "source_url",
+            "document_revision",
+            "entry_date",
+            "model_string",
+            "nominal_capacity_bytes",
+        ]
+        for field in required_fields:
+            if field not in data:
+                print(f"Error: Missing required field: {field}", file=sys.stderr)
+                sys.exit(1)
+
+        # One active row replaced on edit (§6.2)
+        conn.execute("DELETE FROM endurance_baseline")
+        conn.execute(
+            """
+            INSERT INTO endurance_baseline (
+                tbw_terabytes, source_url, document_revision,
+                entry_date, model_string, nominal_capacity_bytes,
+                validated_by, verified, created_at, updated_at
+            ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+            """,
+            (
+                data["tbw_terabytes"],
+                data["source_url"],
+                data["document_revision"],
+                data["entry_date"],
+                data["model_string"],
+                data["nominal_capacity_bytes"],
+                data.get("validated_by", "user"),
+                data.get("verified", False),
+                now.isoformat(),
+                now.isoformat(),
+            ),
+        )
+        conn.commit()
+        print("Baseline persisted")
+    finally:
+        conn.close()
+
+
+def cmd_baseline_clear(args: argparse.Namespace) -> None:
+    """Clear the endurance baseline.
+
+    Spec PR-14: baseline clear persists through polkit-guarded helper.
+    """
+    store_path = getattr(args, 'store_path', DEFAULT_STORE_PATH)
+    if not store_path.exists():
+        print("Error: Observation store not found at", store_path, file=sys.stderr)
+        sys.exit(1)
+
+    conn = init_store(store_path)
+    try:
+        conn.execute("DELETE FROM endurance_baseline")
+        conn.commit()
+        print("Baseline cleared")
+    finally:
+        conn.close()
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser(
+        prog="fenris-monitor",
+        description="Fenris privileged helper for toggle, collect, and baseline operations.",
+    )
+    subparsers = parser.add_subparsers(dest="command", required=True)
+
+    # enable/disable
+    enable_parser = subparsers.add_parser("enable", help="Enable monitoring")
+    enable_parser.add_argument(
+        "--now", action="store_true", help="Also start the timer immediately"
+    )
+    enable_parser.set_defaults(func=cmd_enable)
+
+    disable_parser = subparsers.add_parser("disable", help="Disable monitoring")
+    disable_parser.add_argument(
+        "--now", action="store_true", help="Also stop the timer immediately"
+    )
+    disable_parser.set_defaults(func=cmd_disable)
+
+    # collect
+    collect_parser = subparsers.add_parser("collect", help="Trigger on-demand collection")
+    collect_parser.set_defaults(func=cmd_collect)
+
+    # baseline
+    baseline_parser = subparsers.add_parser("baseline", help="Baseline operations")
+    baseline_sub = baseline_parser.add_subparsers(dest="baseline_action", required=True)
+
+    baseline_set = baseline_sub.add_parser("set", help="Persist baseline")
+    baseline_set.add_argument("baseline_json", help="Baseline JSON data")
+    baseline_set.set_defaults(func=cmd_baseline_set)
+
+    baseline_clear = baseline_sub.add_parser("clear", help="Clear baseline")
+    baseline_clear.set_defaults(func=cmd_baseline_clear)
+
+    args = parser.parse_args()
+    args.func(args)
+
+
+if __name__ == "__main__":
+    main()

src/fenris/monitoring_periods.py

@@ -0,0 +1,124 @@
+"""Monitoring period bookkeeping per spec §5.2, §8.6, §9.8.
+
+A monitoring period is a span during which Fenris monitoring is enabled.
+Powered-off time stays inside a period; deliberately disabled time does not.
+
+Key contracts:
+- Run finding no open period opens one at the run moment, never backdated (§9.8)
+- Wall-clock outside periods excluded from numerator and denominator (§5.2)
+- End causes: user_disabled, migrated, unknown_gap
+"""
+import sqlite3
+from datetime import datetime
+
+
+def ensure_period_open(conn: sqlite3.Connection, run_time: datetime) -> None:
+    """Ensure a monitoring period is open.  If none exists, open one at run_time.
+
+    Spec §9.8: A collection run finding no open monitoring period opens one
+    at the run moment, never backdated.
+    """
+    if get_open_period(conn) is not None:
+        return  # Already open — no-op
+
+    ts = run_time.isoformat()
+    conn.execute(
+        "INSERT INTO monitoring_periods (started_at) VALUES (?)",
+        (ts,),
+    )
+    conn.commit()
+
+
+def close_period(
+    conn: sqlite3.Connection,
+    closed_at: datetime,
+    end_cause: str,
+) -> None:
+    """Close the current open monitoring period.
+
+    Spec §8.6: Pause with an open period closes it user_disabled.
+    If no period is open, this is a no-op (pause otherwise).
+    """
+    open_period = get_open_period(conn)
+    if open_period is None:
+        return  # No-op
+
+    ts = closed_at.isoformat()
+    conn.execute(
+        "UPDATE monitoring_periods SET ended_at = ?, end_cause = ? WHERE id = ?",
+        (ts, end_cause, open_period["id"]),
+    )
+    conn.commit()
+
+
+def get_open_period(conn: sqlite3.Connection) -> dict | None:
+    """Return the currently open monitoring period, or None."""
+    cursor = conn.execute(
+        "SELECT id, started_at, ended_at, end_cause "
+        "FROM monitoring_periods WHERE ended_at IS NULL LIMIT 1"
+    )
+    row = cursor.fetchone()
+    if row is None:
+        return None
+    return {
+        "id": row[0],
+        "started_at": row[1],
+        "ended_at": row[2],
+        "end_cause": row[3],
+    }
+
+
+def is_inside_period(conn: sqlite3.Connection, ts: datetime) -> bool:
+    """Check if a timestamp falls inside any monitoring period.
+
+    Spec §5.2: Wall-clock outside periods is excluded from numerator/denominator.
+    """
+    ts_str = ts.isoformat()
+    cursor = conn.execute(
+        "SELECT 1 FROM monitoring_periods "
+        "WHERE started_at <= ? AND (ended_at IS NULL OR ended_at > ?) "
+        "LIMIT 1",
+        (ts_str, ts_str),
+    )
+    return cursor.fetchone() is not None
+
+
+def wall_clock_in_periods(
+    conn: sqlite3.Connection,
+    start: datetime,
+    end: datetime,
+) -> int:
+    """Compute total wall-clock seconds between start and end that fall inside
+    any monitoring period.
+
+    Used for denominator computation (§5.2).
+    """
+    start_str = start.isoformat()
+    end_str = end.isoformat()
+
+    cursor = conn.execute(
+        "SELECT started_at, ended_at FROM monitoring_periods "
+        "WHERE ended_at IS NULL OR ended_at > ? "
+        "ORDER BY started_at",
+        (start_str,),
+    )
+
+    total = 0
+    for row in cursor.fetchall():
+        period_start = row[0]
+        period_end = row[1]  # None if open
+
+        # Clip period to [start, end]
+        effective_start = max(period_start, start_str)
+        if period_end is not None:
+            effective_end = min(period_end, end_str)
+        else:
+            effective_end = end_str
+
+        if effective_start < effective_end:
+            # Parse for arithmetic
+            s = datetime.fromisoformat(effective_start)
+            e = datetime.fromisoformat(effective_end)
+            total += int((e - s).total_seconds())
+
+    return total

src/fenris/preferences.py

@@ -0,0 +1,98 @@
+"""User-scoped TUI preferences (issue #80).
+
+Persists theme preset and reduced-motion choice per unprivileged user.
+Preferences live at XDG_CONFIG_HOME/fenris/preferences.json and must not
+affect collection, projection, history evidence, helper state, package
+config, or CLI status.
+
+Safe failures: invalid/unreadable/unwritable data never crashes the
+dashboard, corrupts previous preferences, or affects monitoring.
+Failures are understandable rather than silently implying persistence
+succeeded.
+
+Criteria: TPH-10, AC80-2, AC80-3.
+"""
+import json
+import os
+from pathlib import Path
+from typing import Any, Dict
+
+
+PREFERENCE_FILE_NAME = "preferences.json"
+VALID_THEMES = {"amber", "nord", "high_contrast"}
+DEFAULT_THEME = "amber"
+DEFAULT_REDUCED_MOTION = False
+
+
+def get_preference_path() -> Path:
+    """Return the user-scoped preference file path.
+
+    Uses XDG_CONFIG_HOME/fenris/preferences.json.
+    Falls back to ~/.config/fenris/preferences.json if unset.
+    """
+    xdg = os.environ.get("XDG_CONFIG_HOME")
+    if xdg:
+        base = Path(xdg)
+    else:
+        base = Path.home() / ".config"
+    return base / "fenris" / PREFERENCE_FILE_NAME
+
+
+def load_preferences() -> Dict[str, Any]:
+    """Load user preferences with safe defaults.
+
+    Returns a dict with keys:
+      theme: str (one of VALID_THEMES)
+      reduced_motion: bool
+
+    If the file is missing, corrupt, unreadable, or contains invalid
+    values, returns safe defaults (Amber theme, normal motion).
+    """
+    path = get_preference_path()
+
+    try:
+        text = path.read_text()
+    except (OSError, FileNotFoundError):
+        return _defaults()
+
+    try:
+        data = json.loads(text)
+    except (json.JSONDecodeError, ValueError):
+        return _defaults()
+
+    if not isinstance(data, dict):
+        return _defaults()
+
+    theme = data.get("theme", DEFAULT_THEME)
+    if theme not in VALID_THEMES:
+        theme = DEFAULT_THEME
+
+    reduced_motion = data.get("reduced_motion", DEFAULT_REDUCED_MOTION)
+    if not isinstance(reduced_motion, bool):
+        reduced_motion = DEFAULT_REDUCED_MOTION
+
+    return {"theme": theme, "reduced_motion": reduced_motion}
+
+
+def save_preferences(theme: str = DEFAULT_THEME,
+                     reduced_motion: bool = DEFAULT_REDUCED_MOTION) -> None:
+    """Save user preferences.
+
+    Creates the config directory if needed.  If the write fails
+    (read-only filesystem, permissions), the failure is swallowed —
+    the TUI continues with whatever was loaded, and the user sees
+    no crash or error.
+    """
+    path = get_preference_path()
+
+    try:
+        path.parent.mkdir(parents=True, exist_ok=True)
+        payload = json.dumps({"theme": theme, "reduced_motion": reduced_motion}, indent=2)
+        path.write_text(payload + "\n")
+    except (OSError, PermissionError):
+        # Best-effort persistence — failure must not crash the TUI
+        pass
+
+
+def _defaults() -> Dict[str, Any]:
+    return {"theme": DEFAULT_THEME, "reduced_motion": DEFAULT_REDUCED_MOTION}

src/fenris/projection.py

@@ -0,0 +1,620 @@
+"""Projection core: the pure-function read path (spec §6).
+
+Recomputes the complete projection contract on every read, never stores
+anything derived.  Takes a read-only observation store connection and an
+injected clock; returns a ProjectionResult with confidence state,
+contributing facts, headline remaining time (when one exists), scenario
+range, Percentage-Used context line, and disclosure text.
+
+Baseline precedence (§6.1):
+  verified override → unverified override → implied → unavailable
+
+Confidence rule table (§6.7):
+  Supported — all conjuncts satisfied
+  Limited   — baseline + positive rate, failing facts shown
+  Unavailable — no applicable baseline / zero rate / identity change
+
+Arithmetic (§6.3):
+  rate      = regime DUW bytes / in-period wall-clock seconds
+  projected = max(E_baseline − W_t, 0) / rate    (rate > 0)
+  E_rated   = entered_TBW × 10¹² bytes
+  E_implied = 100 · W_t / p                       (1 ≤ p ≤ 254)
+
+Criteria: PR-1–PR-17, CI-4.
+"""
+import sqlite3
+from dataclasses import dataclass, field
+from datetime import datetime, timedelta, timezone
+from enum import Enum
+from typing import Any, Dict, List, Optional, Tuple
+
+
+# ---------------------------------------------------------------------------
+# Constants (spec §6)
+# ---------------------------------------------------------------------------
+
+HORIZON_DAYS = (7, 28, 90)
+TBW_TO_BYTES = 10 ** 12
+IMPLIED_P_MIN = 1
+IMPLIED_P_MAX = 254
+IMPLIED_MIN_PU_INCREMENTS = 2
+WARMING_MIN_DAYS = 14
+WARMING_MAX_LOW_COVERAGE = 2
+WARMING_COVERAGE_FLOOR = 0.50
+SUPPORTED_COVERAGE_FLOOR = 0.80
+HORIZON_AGREEMENT_FACTOR = 2
+BURST_GUARD_FRACTION = 0.50
+BURST_GUARD_LOOKBACK = 28
+YOUNG_REGIME_DAYS = 7
+HABIT_CHANGE_SHORT_WINDOW = 7
+HABIT_CHANGE_LONG_WINDOW = 28
+HABIT_CHANGE_UPPER_FACTOR = 2
+HABIT_CHANGE_LOWER_FACTOR = 0.5
+HABIT_CHANGE_CONSECUTIVE_DAYS = 3
+STALENESS_HOURS = 48
+WEAR_DISAGREEMENT_FACTOR = 2
+
+
+class ConfidenceState(Enum):
+    UNSUPPORTED = "Unavailable"
+    LIMITED = "Limited"
+    SUPPORTED = "Supported"
+
+
+class BaselineTier(Enum):
+    VERIFIED = "verified_override"
+    UNVERIFIED = "unverified_override"
+    IMPLIED = "implied"
+    NONE = "none"
+
+
+@dataclass(frozen=True)
+class ScenarioRange:
+    rates: Dict[int, float]
+    min_days: int
+    max_days: int
+    horizon_reasons: Dict[int, str] = field(default_factory=dict)
+
+
+@dataclass(frozen=True)
+class ProjectionResult:
+    confidence_state: ConfidenceState
+    contributing_facts: List[str]
+    headline_remaining_seconds: Optional[float]
+    scenario_range: Optional[ScenarioRange]
+    pu_context_line: str
+    disclosure_text: List[str]
+    baseline_tier: BaselineTier
+    baseline_label: str
+    regime_days: Optional[int]
+    habit_change_fact: Optional[str]
+    warming_fact: Optional[str]
+    staleness_fact: Optional[str]
+    degraded_identity_fact: Optional[str]
+    zero_rate_fact: Optional[str]
+    qualifying_days_progress: Optional[str] = None  # Issue #77: honest qualifying-day progress
+
+
+# ---------------------------------------------------------------------------
+# Store queries
+# ---------------------------------------------------------------------------
+
+def _get_baseline(conn: sqlite3.Connection) -> Optional[Dict[str, Any]]:
+    cursor = conn.execute(
+        "SELECT id, tbw_terabytes, source_url, document_revision, entry_date, "
+        "       model_string, nominal_capacity_bytes, validated_by, verified "
+        "FROM endurance_baseline LIMIT 1"
+    )
+    row = cursor.fetchone()
+    if row is None:
+        return None
+    return {
+        "id": row[0], "tbw_terabytes": row[1], "source_url": row[2],
+        "document_revision": row[3], "entry_date": row[4],
+        "model_string": row[5], "nominal_capacity_bytes": row[6],
+        "validated_by": row[7], "verified": bool(row[8]),
+    }
+
+
+def _get_current_segment(conn: sqlite3.Connection) -> Optional[Dict[str, Any]]:
+    cursor = conn.execute(
+        "SELECT id, opened_at, identity_key, identity_degraded, mn "
+        "FROM controller_segments ORDER BY id DESC LIMIT 1"
+    )
+    row = cursor.fetchone()
+    if row is None:
+        return None
+    return {
+        "id": row[0], "opened_at": row[1], "identity_key": row[2],
+        "identity_degraded": bool(row[3]), "mn": row[4],
+    }
+
+
+def _get_days_in_segment(conn, segment_opened_at):
+    cursor = conn.execute(
+        "SELECT day, bytes_written_delta, coverage, sample_count "
+        "FROM day_aggregates WHERE day >= ? ORDER BY day",
+        (segment_opened_at[:10],),
+    )
+    return [{"day": r[0], "bytes_written": r[1], "coverage": r[2], "sample_count": r[3]}
+            for r in cursor.fetchall()]
+
+
+def _get_all_days(conn):
+    cursor = conn.execute(
+        "SELECT day, bytes_written_delta, coverage, sample_count "
+        "FROM day_aggregates ORDER BY day"
+    )
+    return [{"day": r[0], "bytes_written": r[1], "coverage": r[2], "sample_count": r[3]}
+            for r in cursor.fetchall()]
+
+
+def _get_latest_pu(conn):
+    cursor = conn.execute("SELECT percentage_used FROM samples ORDER BY id DESC LIMIT 1")
+    row = cursor.fetchone()
+    return row[0] if row else None
+
+
+def _get_pu_increments_in_segment(conn, segment_opened_at):
+    cursor = conn.execute(
+        "SELECT COUNT(DISTINCT percentage_used) FROM samples WHERE ts >= ?",
+        (segment_opened_at,),
+    )
+    row = cursor.fetchone()
+    return max(0, (row[0] if row else 0) - 1)
+
+
+def _wall_clock_in_range(conn, start, end):
+    start_str = start.isoformat()
+    end_str = end.isoformat()
+    cursor = conn.execute(
+        "SELECT started_at, ended_at FROM monitoring_periods "
+        "WHERE (ended_at IS NULL OR ended_at > ?) AND started_at < ? "
+        "ORDER BY started_at", (start_str, end_str),
+    )
+    total = 0
+    for row in cursor.fetchall():
+        eff_start = max(row[0], start_str)
+        eff_end = min(row[1], end_str) if row[1] is not None else end_str
+        if eff_start < eff_end:
+            total += int((datetime.fromisoformat(eff_end) - datetime.fromisoformat(eff_start)).total_seconds())
+    return total
+
+
+# ---------------------------------------------------------------------------
+# Baseline resolution (§6.1, §6.2)
+# ---------------------------------------------------------------------------
+
+def _resolve_baseline(conn, current_segment):
+    baseline = _get_baseline(conn)
+    facts = []
+    if baseline is None:
+        return BaselineTier.NONE, None, "no baseline", facts
+
+    mandatory = [baseline["source_url"], baseline["document_revision"],
+                 baseline["entry_date"], baseline["model_string"],
+                 baseline["nominal_capacity_bytes"]]
+    provenance_complete = all(f is not None and f != "" for f in mandatory)
+
+    model_matches = True
+    if current_segment is not None and baseline["model_string"] is not None:
+        seg_mn = (current_segment.get("mn") or "").lower()
+        bl_model = (baseline["model_string"] or "").lower()
+        model_matches = bl_model in seg_mn or seg_mn in bl_model
+
+    if provenance_complete and model_matches and baseline["verified"]:
+        label = "verified manufacturer TBW (%.1f TB)" % baseline["tbw_terabytes"]
+        return BaselineTier.VERIFIED, baseline, label, facts
+
+    if not model_matches:
+        facts.append(
+            "baseline model '%s' does not match current drive '%s'"
+            " — baseline retained but not applicable"
+            % (baseline.get("model_string", ""),
+               current_segment.get("mn", "") if current_segment else "")
+        )
+        return BaselineTier.NONE, baseline, "baseline model mismatch", facts
+
+    if not provenance_complete:
+        label = "unverified TBW (%.1f TB) — user-supplied" % baseline["tbw_terabytes"]
+        return BaselineTier.UNVERIFIED, baseline, label, facts
+
+    label = "verified manufacturer TBW (%.1f TB)" % baseline["tbw_terabytes"]
+    return BaselineTier.VERIFIED, baseline, label, facts
+
+
+# ---------------------------------------------------------------------------
+# Rate computation
+# ---------------------------------------------------------------------------
+
+def _compute_regime_rate(days, conn, regime_start_day, clock_now):
+    regime_bytes = sum(d["bytes_written"] for d in days if d["day"] >= regime_start_day)
+    regime_start_dt = datetime.fromisoformat(regime_start_day + "T00:00:00+00:00")
+    regime_wc = _wall_clock_in_range(conn, regime_start_dt, clock_now)
+    if regime_wc <= 0:
+        return None, regime_bytes, 0
+    return regime_bytes / regime_wc, regime_bytes, regime_wc
+
+
+def _compute_horizon_rate(days, conn, horizon_days, evidence_endpoint):
+    """Compute horizon rate anchored at the latest evidence endpoint T.
+
+    Uses exact trailing horizon_days × 86400 seconds from T, not clock_now.
+    Reader refresh alone never moves T or dilutes rates.
+
+    Returns (rate, reason) where reason is None on success or a string
+    describing why the rate is unavailable.
+    """
+    if not days:
+        return None, "no observation history"
+
+    # T is the latest evidence endpoint — the end of the last day aggregate
+    T = datetime.fromisoformat(days[-1]["day"] + "T23:59:59+00:00")
+
+    # Exact trailing start: T minus horizon_days × 86400 seconds
+    h_start = T - timedelta(days=horizon_days)
+    cutoff = h_start.strftime("%Y-%m-%d")
+
+    # History must span the full horizon — no placeholders
+    if days[0]["day"] > cutoff:
+        return None, "%d-day window starts before earliest data" % horizon_days
+
+    h_bytes = sum(d["bytes_written"] for d in days if d["day"] >= cutoff)
+    covered = sum(1 for d in days if d["day"] >= cutoff)
+    if covered == 0:
+        return None, "%d-day window has no data" % horizon_days
+
+    h_wc = _wall_clock_in_range(conn, h_start, T)
+    if h_wc <= 0:
+        return None, "%d-day window has no monitored wall-clock time" % horizon_days
+
+    return h_bytes / h_wc, None
+
+
+# ---------------------------------------------------------------------------
+# Habit change detection (§6.4)
+# ---------------------------------------------------------------------------
+
+def _detect_habit_change(days):
+    """Detect habit change per spec §6.4.
+
+    Trailing 7-day mean >= 2x (or <= 0.5x) the preceding 28-day mean
+    for 3 consecutive days. Returns (change_day, days_since) or None.
+    The first divergence day is the earliest day in the consecutive run.
+    """
+    need = HABIT_CHANGE_SHORT_WINDOW + HABIT_CHANGE_LONG_WINDOW
+    if len(days) < need:
+        return None
+
+    def _ratio_at(end_idx):
+        """Compute 7-day / preceding-28-day mean ratio ending at end_idx."""
+        if end_idx < HABIT_CHANGE_SHORT_WINDOW - 1:
+            return None
+        se = end_idx + 1
+        ss = se - HABIT_CHANGE_SHORT_WINDOW
+        s_bytes = sum(d["bytes_written"] for d in days[ss:se])
+        s_mean = s_bytes / HABIT_CHANGE_SHORT_WINDOW
+        le = ss
+        ls = le - HABIT_CHANGE_LONG_WINDOW
+        if ls < 0:
+            return None
+        l_bytes = sum(d["bytes_written"] for d in days[ls:le])
+        l_mean = l_bytes / HABIT_CHANGE_LONG_WINDOW
+        if l_mean == 0:
+            return None
+        return s_mean / l_mean
+
+    # Scan backwards from the most recent day
+    for i in range(len(days) - 1, HABIT_CHANGE_LONG_WINDOW + HABIT_CHANGE_SHORT_WINDOW - 2, -1):
+        ratio = _ratio_at(i)
+        if ratio is None:
+            continue
+
+        is_upper = ratio >= HABIT_CHANGE_UPPER_FACTOR
+        is_lower = ratio <= HABIT_CHANGE_LOWER_FACTOR
+        if not (is_upper or is_lower):
+            continue
+
+        # Count consecutive days going backwards from i
+        consecutive = 1
+        for j in range(i - 1, HABIT_CHANGE_LONG_WINDOW + HABIT_CHANGE_SHORT_WINDOW - 3, -1):
+            r = _ratio_at(j)
+            if r is None:
+                break
+            if (is_upper and r >= HABIT_CHANGE_UPPER_FACTOR) or \
+               (is_lower and r <= HABIT_CHANGE_LOWER_FACTOR):
+                consecutive += 1
+            else:
+                break
+
+        if consecutive >= HABIT_CHANGE_CONSECUTIVE_DAYS:
+            change_idx = i - consecutive + 1
+            change_day = days[change_idx]["day"]
+            days_since = (datetime.fromisoformat(days[-1]["day"]) - datetime.fromisoformat(change_day)).days
+            return change_day, days_since
+
+    return None
+
+
+# ---------------------------------------------------------------------------
+# Confidence rule table (§6.7)
+# ---------------------------------------------------------------------------
+
+def _evaluate_confidence(tier, rate, regime_days, days, current_segment,
+                         clock_now, warming_days, warming_low_coverage,
+                         habit_change, staleness_hours, scenario_range):
+    facts = []
+
+    if tier == BaselineTier.NONE:
+        facts.append("no applicable endurance baseline")
+        return ConfidenceState.UNSUPPORTED, facts
+
+    if rate is None or rate <= 0:
+        facts.append("no finite projection from this history")
+        return ConfidenceState.UNSUPPORTED, facts
+
+    supported_facts = []
+    failing = False
+
+    # 1. Verified baseline
+    if tier != BaselineTier.VERIFIED:
+        failing = True
+    else:
+        supported_facts.append("verified manufacturer TBW")
+
+    # 2. >= 14 qualifying days
+    qualifying = sum(1 for d in days if d["coverage"] >= WARMING_COVERAGE_FLOOR and d["sample_count"] > 0)
+    if qualifying < WARMING_MIN_DAYS:
+        failing = True
+    else:
+        supported_facts.append("%d calendar days" % qualifying)
+
+    # 3. Coverage >= 80%
+    total_wc = len(days) * 86400
+    total_known = sum(int(d["coverage"] * 86400) for d in days)
+    avg_cov = total_known / total_wc if total_wc > 0 else 0.0
+    if avg_cov < SUPPORTED_COVERAGE_FLOOR:
+        failing = True
+    else:
+        supported_facts.append("%d%% interval coverage" % int(avg_cov * 100))
+
+    # 4. Fresh (< 48h)
+    if staleness_hours is not None and staleness_hours > STALENESS_HOURS:
+        failing = True
+    elif staleness_hours is not None:
+        supported_facts.append("recent data")
+
+    # 5. Horizon agreement
+    if scenario_range is not None and len(scenario_range.rates) >= 2:
+        rl = list(scenario_range.rates.values())
+        if min(rl) > 0 and max(rl) / min(rl) > HORIZON_AGREEMENT_FACTOR:
+            failing = True
+        else:
+            supported_facts.append("%d weekly cycles" % len(scenario_range.rates))
+    else:
+        failing = True
+
+    # 6. Burst guard
+    if not failing and len(days) >= BURST_GUARD_LOOKBACK:
+        t28 = sum(d["bytes_written"] for d in days[-BURST_GUARD_LOOKBACK:])
+        for d in days[-BURST_GUARD_LOOKBACK:]:
+            if t28 > 0 and d["bytes_written"] >= BURST_GUARD_FRACTION * t28:
+                failing = True
+                break
+    if not failing:
+        supported_facts.append("no burst days")
+
+    # 7. Regime >= 7 days
+    if regime_days < YOUNG_REGIME_DAYS:
+        failing = True
+
+    # 8. Degraded identity
+    if current_segment and current_segment.get("identity_degraded"):
+        failing = True
+        facts.append("controller identity unavailable — replacement detection relies on write-counter continuity only")
+
+    if not failing:
+        return ConfidenceState.SUPPORTED, supported_facts
+
+    # Limited
+    limited_facts = list(supported_facts)
+    if staleness_hours is not None and staleness_hours > STALENESS_HOURS:
+        limited_facts.append("newest data %dh old (≥48h)" % staleness_hours)
+    if habit_change is not None:
+        limited_facts.append("usage habit changed %d days ago" % habit_change[1])
+    if regime_days < YOUNG_REGIME_DAYS:
+        limited_facts.append("regime only %d days old (≥7 required)" % regime_days)
+    if current_segment and current_segment.get("identity_degraded"):
+        degraded_fact = "controller identity unavailable — replacement detection relies on write-counter continuity only"
+        if degraded_fact not in limited_facts:
+            limited_facts.append(degraded_fact)
+
+    return ConfidenceState.LIMITED, limited_facts
+
+
+# ---------------------------------------------------------------------------
+# Disclosure text (§6.11)
+# ---------------------------------------------------------------------------
+
+DISCLOSURES = [
+    "This is an endurance projection, not a predicted hardware-failure date.",
+    ("Percentage Used is vendor-specific; 100 means estimated endurance consumed "
+     "but may not mean failure, it can exceed 100, and 255 is saturated."),
+    ("Rated TBW can be a warranty/endurance threshold with separate time and "
+     "eligibility terms, not a failure threshold."),
+    ("DUW is upward-rounded host writes excluding metadata and selected commands, "
+     "not exact physical NAND writes."),
+    ("Projection quality depends on baseline provenance, history duration and "
+     "completeness, recentness, stability, and representative usage cycles; "
+     "future workload and firmware behavior remain outside the observed evidence."),
+    ("Gaps can preserve an aggregate counter delta without preserving hourly "
+     "timing; unexplained and deliberately disabled periods must be distinguished."),
+]
+
+
+# ---------------------------------------------------------------------------
+# PU context line (§6.1)
+# ---------------------------------------------------------------------------
+
+def _build_pu_context_line(conn, rate, days, clock_now):
+    pu = _get_latest_pu(conn)
+    if pu is None:
+        return "Percentage Used: unknown"
+    if rate is None or rate <= 0 or not days:
+        return "Percentage Used: %d%%" % pu
+
+    total_bytes = sum(d["bytes_written"] for d in days)
+    if total_bytes <= 0:
+        return "Percentage Used: %d%%" % pu
+
+    total_days_count = len(days)
+    if total_days_count == 0:
+        return "Percentage Used: %d%%" % pu
+
+    pu_daily = total_bytes / total_days_count
+    obs_daily = rate * 86400
+
+    if pu_daily > 0:
+        ratio = obs_daily / pu_daily
+        if ratio > WEAR_DISAGREEMENT_FACTOR or ratio < 1.0 / WEAR_DISAGREEMENT_FACTOR:
+            return ("Percentage Used: %d%% — vendor wear estimate disagrees "
+                    "with observed write rate (>2× difference)") % pu
+
+    return "Percentage Used: %d%%" % pu
+
+
+# ---------------------------------------------------------------------------
+# Main projection function
+# ---------------------------------------------------------------------------
+
+def compute_projection(conn, clock_now):
+    facts = []
+    habit_change_fact = None
+    warming_fact = None
+    staleness_fact = None
+    degraded_identity_fact = None
+    zero_rate_fact = None
+
+    current_segment = _get_current_segment(conn)
+    tier, baseline, baseline_label, baseline_facts = _resolve_baseline(conn, current_segment)
+    facts.extend(baseline_facts)
+
+    segment_days = _get_days_in_segment(conn, current_segment["opened_at"]) if current_segment else _get_all_days(conn)
+    all_days = _get_all_days(conn)
+
+    regime_start_day = None
+    habit_change = None
+
+    if segment_days:
+        earliest = segment_days[0]["day"]
+        cutoff_90 = (clock_now - timedelta(days=90)).strftime("%Y-%m-%d")
+        regime_start_day = max(earliest, cutoff_90)
+        habit_change = _detect_habit_change(segment_days)
+        if habit_change is not None:
+            regime_start_day = habit_change[0]
+            habit_change_fact = "usage habit changed %d days ago" % habit_change[1]
+            facts.append(habit_change_fact)
+
+    rate = None
+    regime_bytes = 0
+    regime_days_count = 0
+
+    if segment_days and regime_start_day is not None:
+        rate, regime_bytes, _ = _compute_regime_rate(segment_days, conn, regime_start_day, clock_now)
+        regime_days_count = sum(1 for d in segment_days if d["day"] >= regime_start_day)
+
+    if rate is not None and rate <= 0:
+        zero_rate_fact = "no finite projection from this history"
+        facts.append(zero_rate_fact)
+
+    scenario = None
+    horizon_rates = {}
+    horizon_reasons = {}
+    for h in HORIZON_DAYS:
+        hr, reason = _compute_horizon_rate(all_days, conn, h, clock_now)
+        if hr is not None:
+            horizon_rates[h] = hr
+        else:
+            horizon_reasons[h] = reason
+    if horizon_rates:
+        scenario = ScenarioRange(
+            rates=horizon_rates,
+            min_days=min(horizon_rates),
+            max_days=max(horizon_rates),
+            horizon_reasons=horizon_reasons,
+        )
+
+    total_days_count = len(segment_days)
+    days_below_coverage = sum(1 for d in segment_days
+                             if d["coverage"] < WARMING_COVERAGE_FLOOR or d["sample_count"] == 0)
+    qualifying = total_days_count - days_below_coverage
+    
+    # Issue #77: Show honest qualifying-day progress
+    if total_days_count >= WARMING_MIN_DAYS:
+        # After warm-up, show qualifying day details for transparency
+        qualifying_days_progress = "%d of %d qualifying days" % (qualifying, total_days_count)
+        if days_below_coverage > 0:
+            qualifying_days_progress += " (%d below coverage)" % days_below_coverage
+    else:
+        qualifying_days_progress = None
+    
+    if total_days_count < WARMING_MIN_DAYS or days_below_coverage > WARMING_MAX_LOW_COVERAGE:
+        warming_fact = "warming up: %d of %d qualifying days" % (qualifying, WARMING_MIN_DAYS)
+        facts.append(warming_fact)
+
+    staleness_hours = None
+    if segment_days:
+        newest_dt = datetime.fromisoformat(segment_days[-1]["day"] + "T12:00:00+00:00")
+        staleness_hours = int((clock_now - newest_dt).total_seconds() / 3600)
+        if staleness_hours > STALENESS_HOURS:
+            staleness_fact = "newest data %dh old (≥48h)" % staleness_hours
+            facts.append(staleness_fact)
+
+    if current_segment and current_segment.get("identity_degraded"):
+        degraded_identity_fact = "controller identity unavailable — replacement detection relies on write-counter continuity only"
+        facts.append(degraded_identity_fact)
+
+    state, conf_facts = _evaluate_confidence(
+        tier, rate, regime_days_count, segment_days, current_segment, clock_now,
+        qualifying, 0, habit_change, staleness_hours, scenario,
+    )
+
+    all_facts = list(facts)
+    for cf in conf_facts:
+        if cf not in all_facts:
+            all_facts.append(cf)
+
+    headline_seconds = None
+    if state != ConfidenceState.UNSUPPORTED and rate is not None and rate > 0 and baseline is not None:
+        if tier in (BaselineTier.VERIFIED, BaselineTier.UNVERIFIED):
+            E_baseline = baseline["tbw_terabytes"] * TBW_TO_BYTES
+        elif tier == BaselineTier.IMPLIED:
+            p = _get_latest_pu(conn)
+            if p is not None and IMPLIED_P_MIN <= p <= IMPLIED_P_MAX:
+                E_baseline = 100 * regime_bytes / p
+            else:
+                E_baseline = None
+        else:
+            E_baseline = None
+        if E_baseline is not None:
+            headline_seconds = max(E_baseline - regime_bytes, 0) / rate
+
+    pu_line = _build_pu_context_line(conn, rate, segment_days, clock_now)
+
+    return ProjectionResult(
+        confidence_state=state,
+        contributing_facts=all_facts,
+        headline_remaining_seconds=headline_seconds,
+        scenario_range=scenario,
+        pu_context_line=pu_line,
+        disclosure_text=list(DISCLOSURES),
+        baseline_tier=tier,
+        baseline_label=baseline_label,
+        regime_days=regime_days_count,
+        habit_change_fact=habit_change_fact,
+        warming_fact=warming_fact,
+        staleness_fact=staleness_fact,
+        degraded_identity_fact=degraded_identity_fact,
+        zero_rate_fact=zero_rate_fact,
+        qualifying_days_progress=qualifying_days_progress,
+    )

src/fenris/pruning.py

@@ -0,0 +1,162 @@
+"""Raw sample pruning per spec §3.4, ST-5.
+
+Raw samples are pruned opportunistically to 14 days.
+Hour observations and day aggregates are retained indefinitely.
+Boundary anchors required for successor evidence are retained.
+"""
+import sqlite3
+from datetime import datetime, timedelta, timezone
+
+# Spec §3.4: Raw-sample retention
+RAW_SAMPLE_RETENTION_DAYS = 14
+
+
+def needs_boundary_anchor(
+    conn: sqlite3.Connection,
+    sample_ts: str,
+    now: datetime,
+) -> bool:
+    """Check if a sample is needed as a boundary anchor for derivation.
+
+    A sample is a boundary anchor if:
+    1. It's older than retention_days (strictly before cutoff)
+    2. It has a next sample that forms an interval spanning the retention boundary
+    3. The interval hasn't been derived yet
+
+    The interval spans the boundary if:
+    - The sample is before the cutoff, AND
+    - The next sample is strictly after the cutoff (or within retention)
+    """
+    from .derive import _parse_ts
+    
+    sample_dt = _parse_ts(sample_ts)
+    retention_cutoff = now - timedelta(days=RAW_SAMPLE_RETENTION_DAYS)
+    
+    # If sample is within retention (strictly after cutoff), not an anchor
+    if sample_dt > retention_cutoff:
+        return False
+    
+    # Check if this sample has a next sample
+    cursor = conn.execute(
+        """SELECT ts, segment_id FROM samples WHERE ts > ? ORDER BY ts LIMIT 1""",
+        (sample_ts,),
+    )
+    next_row = cursor.fetchone()
+    
+    if next_row is None:
+        # No next sample - this is the last sample
+        # It's not needed for derivation (no interval to derive)
+        return False
+    
+    next_ts_str = next_row[0]
+    next_segment_id = next_row[1]
+    next_dt = _parse_ts(next_ts_str)
+    
+    # Check if the next sample is strictly after the cutoff (i.e., interval spans boundary)
+    if next_dt > retention_cutoff:
+        # The interval spans the retention boundary
+        # Check if the interval needs derivation
+        # Get current sample's segment_id
+        cursor = conn.execute(
+            "SELECT segment_id FROM samples WHERE ts = ?",
+            (sample_ts,),
+        )
+        current_segment_row = cursor.fetchone()
+        current_segment_id = current_segment_row[0] if current_segment_row else None
+        
+        # If different segments, no interval to derive
+        if current_segment_id != next_segment_id:
+            return False
+        
+        # Check if the interval [sample_ts, next_ts] needs derivation
+        # It needs derivation if any hour in the span lacks an observation
+        current_hour = sample_dt.replace(minute=0, second=0, microsecond=0)
+        end_hour = next_dt.replace(minute=0, second=0, microsecond=0)
+        
+        while current_hour <= end_hour:
+            cursor = conn.execute(
+                "SELECT id FROM hour_observations WHERE hour = ?",
+                (current_hour.isoformat(),),
+            )
+            if cursor.fetchone() is None:
+                # This hour lacks an observation - interval needs derivation
+                return True
+            current_hour += timedelta(hours=1)
+        
+        # All hours in the span have observations - interval is derived
+        return False
+    else:
+        # The interval doesn't span the boundary (both samples are old)
+        # Check if the interval needs derivation
+        # Get current sample's segment_id
+        cursor = conn.execute(
+            "SELECT segment_id FROM samples WHERE ts = ?",
+            (sample_ts,),
+        )
+        current_segment_row = cursor.fetchone()
+        current_segment_id = current_segment_row[0] if current_segment_row else None
+        
+        # If different segments, no interval to derive
+        if current_segment_id != next_segment_id:
+            return False
+        
+        # Check if the interval [sample_ts, next_ts] needs derivation
+        current_hour = sample_dt.replace(minute=0, second=0, microsecond=0)
+        end_hour = next_dt.replace(minute=0, second=0, microsecond=0)
+        
+        while current_hour <= end_hour:
+            cursor = conn.execute(
+                "SELECT id FROM hour_observations WHERE hour = ?",
+                (current_hour.isoformat(),),
+            )
+            if cursor.fetchone() is None:
+                # This hour lacks an observation - interval needs derivation
+                # But only keep if the interval is significant (spans multiple hours)
+                # or if the next sample is the last sample before a gap
+                gap = (next_dt - sample_dt).total_seconds()
+                if gap > 24 * 3600:  # Significant gap (> 24 hours)
+                    return True
+            current_hour += timedelta(hours=1)
+        
+        # All hours in the span have observations or gap is not significant
+        return False
+
+
+def prune_old_samples(
+    conn: sqlite3.Connection,
+    now: datetime,
+    retention_days: int = RAW_SAMPLE_RETENTION_DAYS,
+) -> int:
+    """Remove raw samples older than retention_days.
+
+    Retains boundary anchors required for successor evidence.
+
+    Args:
+        conn: Connection to the observation store.
+        now: Current UTC time.
+        retention_days: Number of days to retain (default 14).
+
+    Returns:
+        Number of samples removed.
+    """
+    cutoff = (now - timedelta(days=retention_days)).isoformat()
+    
+    # Get all samples older than cutoff
+    cursor = conn.execute(
+        "SELECT id, ts FROM samples WHERE ts < ? ORDER BY ts",
+        (cutoff,),
+    )
+    old_samples = cursor.fetchall()
+    
+    removed = 0
+    for sample_id, sample_ts in old_samples:
+        # Check if this sample is a boundary anchor
+        if needs_boundary_anchor(conn, sample_ts, now):
+            continue  # Skip - it's a boundary anchor
+        
+        # Remove the sample
+        conn.execute("DELETE FROM samples WHERE id = ?", (sample_id,))
+        removed += 1
+    
+    conn.commit()
+    return removed

src/fenris/repair.py

@@ -0,0 +1,448 @@
+"""Historical repair and retention (issue #74).
+
+Re-derives hour observations and day aggregates from surviving raw samples,
+with idempotent and interruption-safe guarantees. Preserves import markers,
+boundary anchors, and valid historical summaries.
+
+Contracts:
+- Idempotent: running repair multiple times produces no duplicates
+- Interruption-safe: partial repair preserves prior valid history
+- Preserves existing valid data: never overwrites valid derived data
+- Surfaces failures explicitly for retry
+"""
+import logging
+import sqlite3
+from dataclasses import dataclass, field
+from datetime import datetime, timedelta, timezone
+from typing import Optional, List, Tuple
+
+from .derive import find_previous_sample, derive_hours_from_interval, _parse_ts
+
+logger = logging.getLogger(__name__)
+
+
+@dataclass
+class RepairResult:
+    """Result of a repair operation."""
+    ok: bool
+    hours_created: int = 0
+    hours_updated: int = 0
+    days_created: int = 0
+    days_updated: int = 0
+    intervals_derived: int = 0
+    boundary_anchors_retained: int = 0
+    legacy_summaries_preserved: int = 0
+    error: Optional[str] = None
+
+
+@dataclass
+class RepairStatus:
+    """Current repair status for read-only views."""
+    last_repair: Optional[str] = None  # ISO timestamp of last successful repair
+    repair_in_progress: bool = False
+    hours_derived: int = 0
+    days_derived: int = 0
+
+
+def _ensure_repair_metadata(conn: sqlite3.Connection) -> None:
+    """Ensure metadata table exists for tracking repair state."""
+    conn.execute("""
+        CREATE TABLE IF NOT EXISTS store_metadata (
+            key TEXT PRIMARY KEY,
+            value TEXT NOT NULL
+        )
+    """)
+
+
+def is_repair_in_progress(conn: sqlite3.Connection) -> bool:
+    """Check if a repair operation is currently in progress."""
+    _ensure_repair_metadata(conn)
+    cursor = conn.execute(
+        "SELECT value FROM store_metadata WHERE key = 'repair_in_progress'"
+    )
+    row = cursor.fetchone()
+    return row is not None and row[0] == "true"
+
+
+def _set_repair_in_progress(conn: sqlite3.Connection, in_progress: bool) -> None:
+    """Mark repair as in progress or complete."""
+    _ensure_repair_metadata(conn)
+    conn.execute(
+        "INSERT OR REPLACE INTO store_metadata (key, value) VALUES (?, ?)",
+        ("repair_in_progress", "true" if in_progress else "false"),
+    )
+    conn.commit()
+
+
+def _update_repair_status(conn: sqlite3.Connection, result: RepairResult) -> None:
+    """Update repair status after successful completion."""
+    _ensure_repair_metadata(conn)
+    now = datetime.now(timezone.utc).isoformat()
+    
+    # Update last repair timestamp
+    conn.execute(
+        "INSERT OR REPLACE INTO store_metadata (key, value) VALUES (?, ?)",
+        ("last_repair", now),
+    )
+    
+    # Update derived counts
+    cursor = conn.execute("SELECT COUNT(*) FROM hour_observations")
+    hours = cursor.fetchone()[0]
+    
+    cursor = conn.execute("SELECT COUNT(*) FROM day_aggregates")
+    days = cursor.fetchone()[0]
+    
+    conn.execute(
+        "INSERT OR REPLACE INTO store_metadata (key, value) VALUES (?, ?)",
+        ("hours_derived", str(hours)),
+    )
+    conn.execute(
+        "INSERT OR REPLACE INTO store_metadata (key, value) VALUES (?, ?)",
+        ("days_derived", str(days)),
+    )
+    
+    conn.commit()
+
+
+def get_repair_status(conn: sqlite3.Connection) -> RepairStatus:
+    """Get current repair status for read-only views."""
+    _ensure_repair_metadata(conn)
+    
+    last_repair = None
+    cursor = conn.execute(
+        "SELECT value FROM store_metadata WHERE key = 'last_repair'"
+    )
+    row = cursor.fetchone()
+    if row:
+        last_repair = row[0]
+    
+    in_progress = is_repair_in_progress(conn)
+    
+    hours_derived = 0
+    cursor = conn.execute(
+        "SELECT value FROM store_metadata WHERE key = 'hours_derived'"
+    )
+    row = cursor.fetchone()
+    if row:
+        hours_derived = int(row[0])
+    
+    days_derived = 0
+    cursor = conn.execute(
+        "SELECT value FROM store_metadata WHERE key = 'days_derived'"
+    )
+    row = cursor.fetchone()
+    if row:
+        days_derived = int(row[0])
+    
+    return RepairStatus(
+        last_repair=last_repair,
+        repair_in_progress=in_progress,
+        hours_derived=hours_derived,
+        days_derived=days_derived,
+    )
+
+
+def needs_boundary_anchor(
+    conn: sqlite3.Connection,
+    sample_ts: str,
+    now: datetime,
+) -> bool:
+    """Check if a sample is needed as a boundary anchor for derivation.
+
+    A sample is a boundary anchor if:
+    1. It's older than retention_days
+    2. It has no derived hour observation for its hour
+    3. It's the last sample before a gap that needs derivation (gap > 24 hours)
+    """
+    from .pruning import RAW_SAMPLE_RETENTION_DAYS
+    
+    sample_dt = _parse_ts(sample_ts)
+    retention_cutoff = now - timedelta(days=RAW_SAMPLE_RETENTION_DAYS)
+    
+    # If sample is within retention, not an anchor (will be kept anyway)
+    if sample_dt >= retention_cutoff:
+        return False
+    
+    # Check if this sample's hour already has a derived observation
+    hour_start = sample_dt.replace(minute=0, second=0, microsecond=0).isoformat()
+    hour_end = (sample_dt + timedelta(hours=1)).replace(minute=0, second=0, microsecond=0).isoformat()
+    
+    cursor = conn.execute(
+        """SELECT COUNT(*) FROM hour_observations 
+           WHERE hour >= ? AND hour < ?""",
+        (hour_start, hour_end),
+    )
+    
+    # If there's an hour observation in this sample's hour, it's been derived
+    if cursor.fetchone()[0] > 0:
+        return False
+    
+    # Check if this sample is the last sample before a gap
+    # (i.e., the next sample is significantly later)
+    cursor = conn.execute(
+        """SELECT ts FROM samples WHERE ts > ? ORDER BY ts LIMIT 1""",
+        (sample_ts,),
+    )
+    next_row = cursor.fetchone()
+    
+    if next_row is None:
+        # No next sample - this is the last sample, might be needed
+        # But if it's old and fully derived, it's not needed
+        return False
+    
+    next_ts = _parse_ts(next_row[0])
+    gap = (next_ts - sample_dt).total_seconds()
+    
+    # If gap > 24 hours, this sample is a boundary anchor
+    # (needed to derive the interval spanning the gap)
+    return gap > 24 * 3600
+
+
+def _get_unlinked_intervals(conn: sqlite3.Connection) -> List[Tuple[dict, dict]]:
+    """Find sample pairs that form intervals but have no hour observations."""
+    cursor = conn.execute(
+        """SELECT id, ts, bytes_written, bytes_read, power_on_hours,
+                  temperature_c, data_units_written, data_units_read, segment_id
+           FROM samples ORDER BY ts"""
+    )
+    
+    all_samples = []
+    for row in cursor.fetchall():
+        all_samples.append({
+            "id": row[0], "ts": row[1], "bytes_written": row[2],
+            "bytes_read": row[3], "power_on_hours": row[4],
+            "temperature_c": row[5], "data_units_written": row[6],
+            "data_units_read": row[7], "segment_id": row[8],
+        })
+    
+    intervals = []
+    for i in range(len(all_samples) - 1):
+        prev = all_samples[i]
+        next_s = all_samples[i + 1]
+        
+        # Skip if different segments
+        if prev["segment_id"] != next_s["segment_id"]:
+            continue
+        
+        # Check if the interval spans hours that need derivation
+        prev_dt = _parse_ts(prev["ts"])
+        next_dt = _parse_ts(next_s["ts"])
+        
+        # Check if any hour in the span lacks an observation
+        current = prev_dt.replace(minute=0, second=0, microsecond=0)
+        end = next_dt.replace(minute=0, second=0, microsecond=0)
+        
+        needs_derivation = False
+        while current <= end:
+            cursor2 = conn.execute(
+                "SELECT id FROM hour_observations WHERE hour = ?",
+                (current.isoformat(),),
+            )
+            if cursor2.fetchone() is None:
+                needs_derivation = True
+                break
+            current += timedelta(hours=1)
+        
+        if needs_derivation:
+            intervals.append((prev, next_s))
+    
+    return intervals
+
+
+def _derive_day_aggregate_from_hours(
+    conn: sqlite3.Connection,
+    day: str,
+) -> Optional[dict]:
+    """Derive a day aggregate from its hour observations."""
+    cursor = conn.execute(
+        """SELECT SUM(active_seconds), SUM(idle_seconds), 
+                  SUM(powered_off_seconds), SUM(unknown_seconds),
+                  SUM(bytes_written_delta), SUM(bytes_read_delta),
+                  SUM(sample_count)
+           FROM hour_observations WHERE hour LIKE ?""",
+        (day + "T%",),
+    )
+    
+    row = cursor.fetchone()
+    if row is None or row[0] is None:
+        return None
+    
+    return {
+        "day": day,
+        "active_seconds": row[0] or 0,
+        "idle_seconds": row[1] or 0,
+        "powered_off_seconds": row[2] or 0,
+        "unknown_seconds": row[3] or 0,
+        "bytes_written_delta": row[4] or 0,
+        "bytes_read_delta": row[5] or 0,
+        "sample_count": row[6] or 0,
+    }
+
+
+def _upsert_day_aggregate(conn: sqlite3.Connection, day_data: dict) -> bool:
+    """Insert or update a day aggregate. Returns True if created."""
+    existing = conn.execute(
+        "SELECT id FROM day_aggregates WHERE day = ?",
+        (day_data["day"],),
+    ).fetchone()
+    
+    if existing is None:
+        # Calculate coverage
+        total_seconds = (day_data["active_seconds"] + day_data["idle_seconds"] + 
+                        day_data["powered_off_seconds"] + day_data["unknown_seconds"])
+        coverage = (day_data["active_seconds"] + day_data["idle_seconds"] + 
+                   day_data["powered_off_seconds"]) / total_seconds if total_seconds > 0 else 0.0
+        
+        conn.execute(
+            """INSERT INTO day_aggregates 
+               (day, active_seconds, idle_seconds, powered_off_seconds, unknown_seconds,
+                bytes_written_delta, bytes_read_delta, sample_count, coverage)
+               VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)""",
+            (day_data["day"], day_data["active_seconds"], day_data["idle_seconds"],
+             day_data["powered_off_seconds"], day_data["unknown_seconds"],
+             day_data["bytes_written_delta"], day_data["bytes_read_delta"],
+             day_data["sample_count"], coverage),
+        )
+        return True
+    else:
+        # Update existing (but only if new data is more complete)
+        # This implements the "don't overwrite valid older history" rule
+        cursor = conn.execute(
+            """SELECT bytes_written_delta, sample_count 
+               FROM day_aggregates WHERE day = ?""",
+            (day_data["day"],),
+        )
+        existing_data = cursor.fetchone()
+        
+        # Only update if new data has more samples or more bytes
+        if (day_data["sample_count"] > existing_data[1] or
+            day_data["bytes_written_delta"] > existing_data[0]):
+            
+            total_seconds = (day_data["active_seconds"] + day_data["idle_seconds"] + 
+                            day_data["powered_off_seconds"] + day_data["unknown_seconds"])
+            coverage = (day_data["active_seconds"] + day_data["idle_seconds"] + 
+                       day_data["powered_off_seconds"]) / total_seconds if total_seconds > 0 else 0.0
+            
+            conn.execute(
+                """UPDATE day_aggregates SET 
+                   active_seconds = ?, idle_seconds = ?, powered_off_seconds = ?,
+                   unknown_seconds = ?, bytes_written_delta = ?, bytes_read_delta = ?,
+                   sample_count = ?, coverage = ?
+                   WHERE day = ?""",
+                (day_data["active_seconds"], day_data["idle_seconds"],
+                 day_data["powered_off_seconds"], day_data["unknown_seconds"],
+                 day_data["bytes_written_delta"], day_data["bytes_read_delta"],
+                 day_data["sample_count"], coverage, day_data["day"]),
+            )
+            return False  # Updated, not created
+        else:
+            return False  # No update needed
+
+
+def repair_derivation(
+    conn: sqlite3.Connection,
+    clock=None,
+) -> RepairResult:
+    """Repair hour observations and day aggregates from surviving samples.
+
+    This is the main entry point for historical repair. It:
+    1. Finds sample pairs that need interval derivation
+    2. Derives hour observations from those intervals
+    3. Updates day aggregates from the hour observations
+    4. Preserves existing valid data
+    5. Is idempotent and interruption-safe
+
+    Args:
+        conn: Connection to the observation store
+        clock: Injected clock (for testing)
+
+    Returns:
+        RepairResult with operation details
+    """
+    if clock is None:
+        clock = datetime.now(timezone.utc)
+    elif hasattr(clock, 'utcnow'):
+        clock = clock.utcnow()
+    
+    # Check if repair is already in progress
+    if is_repair_in_progress(conn):
+        return RepairResult(
+            ok=False,
+            error="Repair already in progress",
+        )
+    
+    # Mark repair as in progress
+    _set_repair_in_progress(conn, True)
+    
+    result = RepairResult(ok=True)
+    
+    try:
+        # Begin transaction
+        conn.execute("BEGIN IMMEDIATE")
+        
+        # 1. Find and derive intervals from sample pairs
+        intervals = _get_unlinked_intervals(conn)
+        
+        for prev, next_s in intervals:
+            try:
+                derived_hours = derive_hours_from_interval(conn, prev, next_s)
+                result.intervals_derived += 1
+                result.hours_created += len([h for h in derived_hours if h.get("attributed", True)])
+            except Exception as e:
+                logger.warning("Failed to derive interval %s -> %s: %s",
+                             prev["ts"], next_s["ts"], e)
+                # Continue with other intervals (resilient)
+        
+        # 2. Update day aggregates from hour observations
+        cursor = conn.execute(
+            "SELECT DISTINCT substr(hour, 1, 10) as day FROM hour_observations ORDER BY day"
+        )
+        days = [row[0] for row in cursor.fetchall()]
+        
+        for day in days:
+            day_data = _derive_day_aggregate_from_hours(conn, day)
+            if day_data is not None:
+                created = _upsert_day_aggregate(conn, day_data)
+                if created:
+                    result.days_created += 1
+                else:
+                    result.days_updated += 1
+        
+        # 3. Count boundary anchors retained
+        now = clock if isinstance(clock, datetime) else datetime.now(timezone.utc)
+        cursor = conn.execute("SELECT ts FROM samples ORDER BY ts")
+        anchor_count = 0
+        for row in cursor.fetchall():
+            if needs_boundary_anchor(conn, row[0], now):
+                anchor_count += 1
+        result.boundary_anchors_retained = anchor_count
+        
+        # 4. Count preserved legacy summaries
+        # Legacy summaries are day aggregates without corresponding hour observations
+        cursor = conn.execute(
+            """SELECT COUNT(*) FROM day_aggregates d 
+               WHERE NOT EXISTS (
+                   SELECT 1 FROM hour_observations h 
+                   WHERE h.hour LIKE d.day || 'T%'
+               )"""
+        )
+        result.legacy_summaries_preserved = cursor.fetchone()[0]
+        
+        # Commit transaction
+        conn.commit()
+        
+        # Update repair status
+        _update_repair_status(conn, result)
+        
+    except Exception as e:
+        conn.rollback()
+        logger.error("Repair failed: %s", e)
+        return RepairResult(
+            ok=False,
+            error=str(e),
+        )
+    finally:
+        # Mark repair as complete
+        _set_repair_in_progress(conn, False)
+    
+    return result

src/fenris/segment.py

@@ -0,0 +1,147 @@
+"""Controller segment management.
+
+Handles identity-based segmentation of observation history:
+- Find current (most recent) segment
+- Determine if a new segment should open
+- Open new segments with frozen metadata snapshot
+
+Segmentation axes (independent):
+- Identity key change → quarantines prior history
+- DUW decrease with unchanged identity → new segment, prior history stays as habit evidence
+
+Blank-key semantics (PR-16):
+- To/from blank is an identity change → quarantines
+- Equal blanks continue the segment, segmented by DUW monotonicity alone
+"""
+import sqlite3
+from datetime import datetime
+from typing import Any, Dict, Optional, Tuple
+
+from .collector import normalize_identity
+
+
+def find_current_segment(conn: sqlite3.Connection) -> Optional[Dict[str, Any]]:
+    """Find the most recent (open) controller segment.
+    
+    Returns the segment dict or None if no segments exist.
+    """
+    cursor = conn.execute(
+        "SELECT id, opened_at, identity_key, identity_degraded, "
+        "subnqn, sn, mn, fr, vid, ssvid, transport "
+        "FROM controller_segments ORDER BY id DESC LIMIT 1"
+    )
+    row = cursor.fetchone()
+    if row is None:
+        return None
+    
+    return {
+        "id": row[0],
+        "opened_at": row[1],
+        "identity_key": row[2],
+        "identity_degraded": bool(row[3]),
+        "subnqn": row[4],
+        "sn": row[5],
+        "mn": row[6],
+        "fr": row[7],
+        "vid": row[8],
+        "ssvid": row[9],
+        "transport": row[10],
+    }
+
+
+def get_last_duw(conn: sqlite3.Connection, segment_id: int) -> Optional[int]:
+    """Get the bytes_written from the most recent sample in a segment.
+    
+    Returns None if no samples exist in the segment.
+    """
+    # Samples don't have a segment_id FK yet, so we need to find the
+    # latest sample before the segment's opened_at, or the latest sample
+    # if this is the first segment.
+    #
+    # For now, we'll use a simpler approach: get the latest sample's bytes_written.
+    # TODO: Add segment_id FK to samples table in next schema migration
+    cursor = conn.execute(
+        "SELECT bytes_written FROM samples ORDER BY id DESC LIMIT 1"
+    )
+    row = cursor.fetchone()
+    return row[0] if row else None
+
+
+def should_open_new_segment(
+    current_segment: Optional[Dict[str, Any]],
+    new_identity_key: str,
+    new_bytes_written: int,
+    conn: sqlite3.Connection,
+) -> Tuple[bool, Optional[str]]:
+    """Determine if a new segment should open.
+    
+    Returns (should_open, reason).
+    reason is None if no new segment, or a string describing why.
+    """
+    # No current segment → must open first segment
+    if current_segment is None:
+        return True, "first_segment"
+    
+    old_key = current_segment["identity_key"] or ""
+    
+    # Identity key change (including to/from blank)
+    if old_key != new_identity_key:
+        return True, "identity_change"
+    
+    # DUW decrease (counter reset or controller replacement with same identity)
+    last_duw = get_last_duw(conn, current_segment["id"])
+    if last_duw is not None and new_bytes_written < last_duw:
+        return True, "duw_decrease"
+    
+    # Same identity, DUW non-decreasing → continue segment
+    return False, None
+
+
+
+def open_segment(
+    conn: sqlite3.Connection,
+    now: datetime,
+    identity: Dict[str, Any],
+    identity_key: str,
+    identity_degraded: bool,
+) -> Dict[str, Any]:
+    """Open a new controller segment with frozen metadata snapshot.
+    
+    The metadata is immutable once frozen.
+    """
+    cursor = conn.execute(
+        """
+        INSERT INTO controller_segments (
+            opened_at, identity_key, identity_degraded,
+            subnqn, sn, mn, fr, vid, ssvid, transport
+        ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+        """,
+        (
+            now.isoformat(),
+            identity_key if identity_key else None,
+            identity_degraded,
+            identity.get("subnqn") or None,
+            identity.get("sn") or None,
+            identity.get("mn") or None,
+            identity.get("fr") or None,
+            identity.get("vid") or None,
+            identity.get("ssvid") or None,
+            identity.get("transport") or None,
+        ),
+    )
+    
+    segment_id = cursor.lastrowid
+    
+    return {
+        "id": segment_id,
+        "opened_at": now.isoformat(),
+        "identity_key": identity_key if identity_key else None,
+        "identity_degraded": identity_degraded,
+        "subnqn": identity.get("subnqn") or None,
+        "sn": identity.get("sn") or None,
+        "mn": identity.get("mn") or None,
+        "fr": identity.get("fr") or None,
+        "vid": identity.get("vid") or None,
+        "ssvid": identity.get("ssvid") or None,
+        "transport": identity.get("transport") or None,
+    }

src/fenris/status.py

@@ -0,0 +1,683 @@
+"""Read-only CLI status command: the CLI twin of the TUI (spec §8.8, LC-9, CI-2).
+
+Composes from the observation store (read-only) and allow-listed service
+properties: projection facts, four separate service facts (boot enablement,
+runtime activity, last collect outcome, freshness), and a journal/log hint on
+failure or staleness.  Never auto-samples, never prompts.
+
+Freshness constants are defined once here and shared with the TUI (§8.9):
+  fresh   — newest sample within 2 × cadence + AccuracySec + 60 s
+  missed  — between fresh and 48 h
+  stale   — ≥ 48 h
+  empty   — no observations yet
+
+Criteria: LC-9, CI-2, CI-4, FL-4, FL-5, FL-7.
+"""
+import sqlite3
+import sys
+from datetime import datetime, timedelta, timezone
+from pathlib import Path
+from typing import Any, Dict, List, Optional, Tuple
+
+from .projection import compute_projection, ConfidenceState, DISCLOSURES
+from .store import SCHEMA_VERSION
+from .init_system import (
+    query_service_state as _init_query_service_state,
+    journal_hint as _init_journal_hint,
+)
+
+
+# ---------------------------------------------------------------------------
+# Freshness constants (§8.9, §8.2)
+# ---------------------------------------------------------------------------
+
+CADENCE_DEFAULT_S = 300           # 5 min
+ACCURACY_SEC = 30
+FRESH_THRESHOLD_S = 2 * CADENCE_DEFAULT_S + ACCURACY_SEC + 60  # 690 s
+STALENESS_THRESHOLD_S = 48 * 3600  # 48 h
+
+
+# ---------------------------------------------------------------------------
+# Configuration reading (§8.3)
+# ---------------------------------------------------------------------------
+
+CONFIG_PATH = Path("/etc/fenris/fenris.conf")
+
+
+def read_config() -> Dict[str, Any]:
+    """Read the world-readable configuration file.
+
+    Returns a dict with at least 'device'.
+    Raises ConfigError with a reason string on any failure.
+    """
+    if not CONFIG_PATH.exists():
+        raise ConfigError("configuration file not found at %s" % CONFIG_PATH)
+
+    try:
+        text = CONFIG_PATH.read_text()
+    except OSError as e:
+        raise ConfigError("cannot read %s: %s" % (CONFIG_PATH, e))
+
+    device = None
+    for line in text.splitlines():
+        line = line.strip()
+        if not line or line.startswith("#"):
+            continue
+        if "=" in line:
+            key, _, value = line.partition("=")
+            key = key.strip()
+            value = value.strip().strip('"').strip("'")
+            if key == "device":
+                device = value
+                break
+
+    if not device:
+        raise ConfigError("no device selector in %s" % CONFIG_PATH)
+
+    return {"device": device}
+
+
+class ConfigError(Exception):
+    """Configuration is invalid — surfaced in status as a fact (§8.3)."""
+    pass
+
+
+# ---------------------------------------------------------------------------
+# Store opening (read-only, §3, §9.4, §9.5)
+# ---------------------------------------------------------------------------
+
+def open_store_readonly(store_path: Path) -> sqlite3.Connection:
+    """Open the observation store read-only.
+
+    Raises StoreFault if unreadable, NewerSchema if user_version > SCHEMA_VERSION.
+    """
+    try:
+        exists = store_path.exists()
+    except OSError as e:
+        # A non-group user stat()ing a 2750 store directory gets
+        # PermissionError before any StoreFault can be raised (issue #54).
+        raise StoreFault("observation store not readable: %s" % e)
+    if not exists:
+        raise StoreFault("observation store not found at %s" % store_path)
+
+    try:
+        conn = sqlite3.connect("file:%s?mode=ro" % store_path, uri=True)
+        conn.row_factory = sqlite3.Row
+    except sqlite3.Error as e:
+        raise StoreFault("observation store unreadable: %s" % e)
+
+    try:
+        cursor = conn.execute("PRAGMA user_version")
+        version = cursor.fetchone()[0]
+    except sqlite3.Error as e:
+        conn.close()
+        raise StoreFault("observation store unreadable: %s" % e)
+
+    if version > SCHEMA_VERSION:
+        conn.close()
+        raise NewerSchema(version)
+
+    return conn
+
+
+class StoreFault(Exception):
+    """Store is present but unreadable or corrupt (§9.4)."""
+    pass
+
+
+class NewerSchema(Exception):
+    """Store has a newer user_version (§9.5)."""
+    def __init__(self, version: int):
+        self.version = version
+        super().__init__("schema version %d" % version)
+
+
+# ---------------------------------------------------------------------------
+# Service state queries (§8.8 — init-system agnostic)
+# ---------------------------------------------------------------------------
+
+# Re-export for backward compatibility with tests that import directly
+query_service_state = _init_query_service_state
+_journalctl_hint = _init_journal_hint
+
+
+# ---------------------------------------------------------------------------
+# Freshness grading (§8.9)
+# ---------------------------------------------------------------------------
+
+def grade_freshness(newest_sample_ts: Optional[str], clock_now: datetime) -> str:
+    """Grade freshness from the newest sample timestamp (never a stored flag).
+
+    Returns 'fresh', 'missed', 'stale', or 'empty'.
+    """
+    if newest_sample_ts is None:
+        return "empty"
+
+    try:
+        ts = datetime.fromisoformat(newest_sample_ts)
+        if ts.tzinfo is None:
+            ts = ts.replace(tzinfo=timezone.utc)
+        else:
+            ts = ts.astimezone(timezone.utc)
+    except (ValueError, TypeError):
+        return "empty"
+
+    age_s = (clock_now - ts).total_seconds()
+
+    if age_s <= FRESH_THRESHOLD_S:
+        return "fresh"
+    elif age_s < STALENESS_THRESHOLD_S:
+        return "missed"
+    else:
+        return "stale"
+
+
+def freshness_age_human(age_s: Optional[int]) -> str:
+    """Human-readable age string for freshness fact."""
+    if age_s is None:
+        return "unknown age"
+    if age_s < 60:
+        return "%ds ago" % age_s
+    if age_s < 3600:
+        return "%dm ago" % (age_s // 60)
+    if age_s < 86400:
+        return "%dh %dm ago" % (age_s // 3600, (age_s % 3600) // 60)
+    return "%dd ago" % (age_s // 86400)
+
+
+# ---------------------------------------------------------------------------
+# Drive anomalies (§9.7 — FL-7)
+# ---------------------------------------------------------------------------
+
+def _query_drive_facts(conn: sqlite3.Connection) -> List[str]:
+    """Query drive-reported anomalies from the latest sample (§9.7, FL-7).
+
+    critical_warning, media errors, and unsafe shutdowns render as ordinary
+    facts and never affect the projection.
+    """
+    cursor = conn.execute(
+        "SELECT critical_warning, media_errors, unsafe_shutdowns, "
+        "temperature_c, available_spare "
+        "FROM samples ORDER BY id DESC LIMIT 1"
+    )
+    row = cursor.fetchone()
+    if row is None:
+        return []
+
+    facts = []
+    cw = row[0]
+    if cw and cw != 0:
+        facts.append("critical warning: %s" % hex(cw) if isinstance(cw, int) else str(cw))
+    me = row[1]
+    if me and me > 0:
+        facts.append("media errors: %d" % me)
+    us = row[2]
+    if us and us > 0:
+        facts.append("unsafe shutdowns: %d" % us)
+    return facts
+
+
+# ---------------------------------------------------------------------------
+# Retired command rejection (§8.8)
+# ---------------------------------------------------------------------------
+
+RETIRED_COMMANDS = {
+    "start": "use 'fenris monitor resume' to enable monitoring",
+    "stop": "use 'fenris monitor pause' to disable monitoring",
+    "run": "use 'fenris monitor resume' to enable monitoring; the timer runs in the background",
+}
+
+MIGRATION_POINTERS = {
+    "--device": "device is configured in /etc/fenris/fenris.conf",
+}
+
+
+def check_retired_command(cmd: str) -> Optional[str]:
+    """Check if a command is retired and return the migration pointer, or None."""
+    return RETIRED_COMMANDS.get(cmd)
+
+
+def check_retired_flag(flag: str) -> Optional[str]:
+    """Check if a flag is retired and return the migration pointer, or None."""
+    return MIGRATION_POINTERS.get(flag)
+
+
+# ---------------------------------------------------------------------------
+# Formatting
+# ---------------------------------------------------------------------------
+
+def _format_projection(proj, freshness: str, service: Dict[str, Any],
+                       drive_facts: List[str], config_error: Optional[str],
+                       store_fault: Optional[str], newer_schema: Optional[str],
+                       journal_hint: Optional[str],
+                       sample_count: int = 0, day_count: int = 0) -> str:
+    """Format the complete status output."""
+    lines = []
+
+    # --- Store/system fault overrides (§9.4, §9.5) ---
+    if store_fault:
+        lines.append("observation store unreadable")
+        if journal_hint:
+            lines.append("")
+            lines.append("Recent journal entries:")
+            lines.append(journal_hint)
+        return "\n".join(lines)
+
+    if newer_schema:
+        lines.append("observation store written by a newer Fenris — upgrade Fenris")
+        return "\n".join(lines)
+
+    # --- Configuration error (§8.3) ---
+    if config_error:
+        lines.append("configuration error: %s" % config_error)
+        lines.append("")
+
+    # --- Empty store (§8.9) ---
+    if freshness == "empty":
+        lines.append("no observations yet")
+        lines.append("")
+        lines.append("Enable monitoring: fenris monitor resume")
+        _append_service_facts(lines, service)
+        return "\n".join(lines)
+
+    # --- Single sample: awaiting another sample (issue #73 AC3) ---
+    # Only show awaiting state when there are no day aggregates (e.g., legacy import
+    # or hand-crafted stores can have 1 sample but sufficient day data for projection)
+    if sample_count <= 1 and day_count == 0:
+        lines.append("awaiting another sample")
+        lines.append("")
+        lines.append("Collecting usage data — the first projection requires at least two samples.")
+        _append_service_facts(lines, service)
+        return "\n".join(lines)
+
+    # --- Projection headline ---
+    headline = _format_headline(proj)
+    lines.append(headline)
+    lines.append("")
+
+    # --- Confidence state + contributing facts (§6.7, §6.11) ---
+    state_label = proj.confidence_state.value
+    facts_list = list(proj.contributing_facts) if proj.contributing_facts else []
+    
+    # Issue #77: Show qualifying day progress for honesty
+    if proj.qualifying_days_progress:
+        facts_list.insert(0, proj.qualifying_days_progress)
+    
+    if facts_list:
+        facts_str = " · ".join(facts_list)
+        lines.append("%s evidence · %s" % (state_label, facts_str))
+    else:
+        lines.append("%s evidence" % state_label)
+    lines.append("")
+
+    # --- Scenario range (§6.5) with horizon reasons ---
+    if proj.scenario_range:
+        parts = []
+        for horizon in sorted(proj.scenario_range.rates.keys()):
+            rate_gb_day = proj.scenario_range.rates[horizon] * 86400 / 1e9
+            parts.append("%dd: %.2f GB/day" % (horizon, rate_gb_day))
+        for horizon, reason in sorted(proj.scenario_range.horizon_reasons.items()):
+            parts.append("%dd: %s" % (horizon, reason))
+        if parts:
+            lines.append("scenario range: %s" % " · ".join(parts))
+            lines.append("")
+
+    # --- PU context line (§6.1) ---
+    lines.append(proj.pu_context_line)
+    lines.append("")
+
+    # --- Drive anomalies (§9.7, FL-7) ---
+    if drive_facts:
+        for fact in drive_facts:
+            lines.append(fact)
+        lines.append("")
+
+    # --- Four separate service facts (§7.3, LC-9) ---
+    _append_service_facts(lines, service)
+
+    # --- Journal hint on failure or staleness (§8.8) ---
+    if journal_hint:
+        if freshness in ("missed", "stale"):
+            lines.append("")
+            lines.append("Recent journal entries:")
+            lines.append(journal_hint)
+
+    return "\n".join(lines)
+
+
+def _format_headline(proj) -> str:
+    """Format the lifespan headline or its no-projection wording (§6.11)."""
+    if proj.headline_remaining_seconds is None:
+        if proj.zero_rate_fact:
+            return "no finite projection from this history"
+        if proj.warming_fact:
+            return proj.warming_fact
+        return "no projection available"
+
+    secs = proj.headline_remaining_seconds
+    if secs <= 0:
+        return "endurance exhausted"
+
+    # Human-readable time
+    years = int(secs // 31557600)
+    rem = secs % 31557600
+    days = int(rem // 86400)
+    rem %= 86400
+    hours = int(rem // 3600)
+
+    parts = []
+    if years:
+        parts.append("%d yr" % years)
+    if days or years:
+        parts.append("%d d" % days)
+    parts.append("%d h" % hours)
+
+    remaining_human = " ".join(parts)
+
+    # Regime line
+    regime_parts = []
+    if proj.regime_days:
+        regime_parts.append("sustained regime: %d days" % proj.regime_days)
+
+    headline = "%s remaining" % remaining_human
+    if regime_parts:
+        headline += " · %s" % " · ".join(regime_parts)
+
+    return headline
+
+
+def _append_service_facts(lines: List[str], service: Dict[str, Any]) -> None:
+    """Append service facts and dashboard-clarity monitoring state."""
+    boot = "enabled" if service.get("boot_enabled") else "disabled"
+    activity = "active" if service.get("timer_active") else "inactive"
+
+    if service.get("last_collect_ok") is True:
+        collect = "ok"
+    elif service.get("last_collect_ok") is False:
+        collect = "FAILED"
+        if service.get("last_collect_reason"):
+            collect += " (%s)" % service["last_collect_reason"]
+    else:
+        collect = "unknown"
+
+    collect_age = ""
+    if service.get("last_collect_age_s") is not None:
+        collect_age = " %s" % freshness_age_human(service["last_collect_age_s"])
+
+    freshness_str = service.get("freshness", "unknown")
+    freshness_age = ""
+    if service.get("freshness_age_s") is not None:
+        freshness_age = " (%s)" % freshness_age_human(service["freshness_age_s"])
+
+    lines.append("boot: %s · timer: %s · last collect: %s%s · freshness: %s%s"
+                 % (boot, activity, collect, collect_age, freshness_str, freshness_age))
+    lines.append("CONTINUITY: %s" % monitoring_continuity(service))
+    if service.get("deliberately_paused"):
+        lines.extend(deliberate_pause_lines())
+
+
+# ---------------------------------------------------------------------------
+# Dashboard clarity parity wording (DC-2, DC-3)
+# ---------------------------------------------------------------------------
+
+_CONTINUITY_ACTIVE = "monitoring: active in background · persists across reboots"
+_CONTINUITY_DISABLED = "monitoring: does not start on next boot"
+_PAUSED_TITLE = "monitoring: paused — deliberate disable"
+_PAUSED_CONSEQUENCE = (
+    "paused time is excluded from your usage habit · resume: fenris monitor resume"
+)
+
+
+def monitoring_continuity(service: Dict[str, Any]) -> str:
+    """Return the boot-persistence wording, independent of timer runtime."""
+    return _CONTINUITY_ACTIVE if service.get("boot_enabled") else _CONTINUITY_DISABLED
+
+
+def deliberate_pause_lines() -> List[str]:
+    """Return the exact CLI/TUI presentation for a sanctioned pause."""
+    return [_PAUSED_TITLE, _PAUSED_CONSEQUENCE]
+
+
+def is_deliberately_paused(conn: sqlite3.Connection, service: Dict[str, Any]) -> bool:
+    """Whether the latest closed period was ended by Fenris's own pause path.
+
+    Raw systemd operations have no `user_disabled` row, so they must never be
+    presented as a Deliberate disable. A live enabled timer also wins over a
+    stale period marker, keeping the presentation consistent with service facts.
+    """
+    if service.get("boot_enabled") or service.get("timer_active"):
+        return False
+
+    open_period = conn.execute(
+        "SELECT 1 FROM monitoring_periods WHERE ended_at IS NULL LIMIT 1"
+    ).fetchone()
+    if open_period is not None:
+        return False
+
+    row = conn.execute(
+        "SELECT end_cause FROM monitoring_periods "
+        "WHERE ended_at IS NOT NULL "
+        "ORDER BY ended_at DESC, id DESC LIMIT 1"
+    ).fetchone()
+    return row is not None and row[0] == "user_disabled"
+
+
+def format_disclosures() -> str:
+    """Format the six disclosures (§6.11, CI-4)."""
+    lines = []
+    lines.append("Disclosures")
+    lines.append("")
+    for i, disc in enumerate(DISCLOSURES, 1):
+        lines.append("%d. %s" % (i, disc))
+    return "\n".join(lines)
+
+
+# ---------------------------------------------------------------------------
+# Main status entry point
+# ---------------------------------------------------------------------------
+
+def get_status(store_path: Optional[Path] = None, clock_now: Optional[datetime] = None,
+               query_services: bool = True, query_journal: bool = True) -> str:
+    """Render the complete read-only status (§8.8, LC-9).
+
+    This is the single entry point for 'fenris status'.  It never auto-samples,
+    never prompts, and never writes to the store.
+    """
+    if clock_now is None:
+        clock_now = datetime.now(timezone.utc)
+
+    # --- Configuration (§8.3) ---
+    config_error = None
+    device = None
+    try:
+        config = read_config()
+        device = config["device"]
+    except ConfigError as e:
+        config_error = str(e)
+
+    # --- Service state ---
+    service = {}
+    if query_services:
+        service = query_service_state()
+
+    # --- Store open ---
+    store_fault = None
+    newer_schema = None
+    conn = None
+
+    if store_path is None:
+        store_path = Path("/var/lib/fenris/observations.db")
+
+    try:
+        conn = open_store_readonly(store_path)
+    except StoreFault as e:
+        store_fault = str(e)
+    except NewerSchema as e:
+        newer_schema = str(e)
+
+    # --- Store fault / newer schema short-circuit ---
+    if store_fault or newer_schema:
+        journal_hint = None
+        if query_journal:
+            journal_hint = _journalctl_hint()
+        service["freshness"] = "unknown"
+        service["freshness_age_s"] = None
+        return _format_projection(
+            None, "unknown", service, [], config_error, store_fault, newer_schema, journal_hint
+        )
+
+    # --- Freshness grading (§8.9) ---
+    try:
+        cursor = conn.execute("SELECT ts FROM samples ORDER BY id DESC LIMIT 1")
+        row = cursor.fetchone()
+        newest_ts = row[0] if row else None
+    except sqlite3.Error:
+        newest_ts = None
+
+    freshness = grade_freshness(newest_ts, clock_now)
+
+    # --- Sample count for single-sample state (issue #73 AC3) ---
+    sample_count = 0
+    day_count = 0
+    try:
+        cursor = conn.execute("SELECT COUNT(*) FROM samples")
+        sample_count = cursor.fetchone()[0]
+        cursor = conn.execute("SELECT COUNT(*) FROM day_aggregates")
+        day_count = cursor.fetchone()[0]
+    except sqlite3.Error:
+        pass
+
+    # Freshness age for the service fact
+    freshness_age_s = None
+    if newest_ts:
+        try:
+            ts = datetime.fromisoformat(newest_ts)
+            if ts.tzinfo is None:
+                ts = ts.replace(tzinfo=timezone.utc)
+            freshness_age_s = int((clock_now - ts).total_seconds())
+        except (ValueError, TypeError):
+            pass
+
+    service["freshness"] = freshness
+    service["freshness_age_s"] = freshness_age_s
+    try:
+        service["deliberately_paused"] = is_deliberately_paused(conn, service)
+    except sqlite3.Error:
+        service["deliberately_paused"] = False
+
+    # --- Drive anomalies (§9.7, FL-7) ---
+    drive_facts = []
+    try:
+        drive_facts = _query_drive_facts(conn)
+    except sqlite3.Error:
+        pass
+
+    # --- Projection (§6 — recomputed on read, never stored) ---
+    try:
+        proj = compute_projection(conn, clock_now)
+    except Exception:
+        proj = None
+
+    # --- Journal hint on failure or staleness (§8.8) ---
+    journal_hint = None
+    if query_journal and freshness in ("missed", "stale"):
+        journal_hint = _journalctl_hint()
+
+    # --- Compose output ---
+    result = _format_projection(
+        proj, freshness, service, drive_facts, config_error,
+        None, None, journal_hint, sample_count, day_count,
+    )
+
+    conn.close()
+    return result
+
+
+def render_status(store_path: Optional[Path] = None, clock_now: Optional[datetime] = None,
+                  query_services: bool = True, query_journal: bool = True,
+                  show_disclosures: bool = False) -> str:
+    """High-level status renderer: status + optional disclosures.
+
+    Used by the CLI entry point.
+    """
+    parts = [get_status(store_path, clock_now, query_services, query_journal)]
+    if show_disclosures:
+        parts.append("")
+        parts.append(format_disclosures())
+    return "\n\n".join(parts)
+
+
+
+# ---------------------------------------------------------------------------
+# Shared status composition integration (issue #78)
+# ---------------------------------------------------------------------------
+
+def get_status_composition(
+    store_path: Optional[Path] = None,
+    clock_now: Optional[datetime] = None,
+    query_services: bool = True,
+    collecting: bool = False,
+    reduced_motion: bool = False,
+) -> 'StatusComposition':
+    """Get the shared status composition consumed by both TUI and CLI.
+
+    This is the new entry point that centralizes the status lattice.
+    """
+    # Lazy import to avoid circular dependency
+    from .status_composition import (
+        StatusComposition,
+        compose_status,
+    )
+
+    if clock_now is None:
+        clock_now = datetime.now(timezone.utc)
+
+    # --- Configuration (§8.3) ---
+    # Config errors are surfaced through the store fault mechanism
+
+    # --- Service state ---
+    service = {}
+    if query_services:
+        try:
+            service = query_service_state()
+        except Exception:
+            service = None
+
+    # --- Store open ---
+    store_fault = None
+    newer_schema = None
+    conn = None
+
+    if store_path is None:
+        store_path = Path("/var/lib/fenris/observations.db")
+
+    try:
+        conn = open_store_readonly(store_path)
+    except StoreFault as e:
+        store_fault = str(e)
+    except NewerSchema as e:
+        newer_schema = str(e)
+
+    # --- Use shared composition ---
+    if conn is not None:
+        try:
+            comp = compose_status(
+                conn, service, clock_now,
+                store_fault=store_fault,
+                newer_schema=newer_schema,
+                collecting=collecting,
+                reduced_motion=reduced_motion,
+            )
+        finally:
+            conn.close()
+    else:
+        # Store fault or newer schema - compose without store data
+        comp = compose_status(
+            None, service, clock_now,
+            store_fault=store_fault,
+            newer_schema=newer_schema,
+            collecting=collecting,
+            reduced_motion=reduced_motion,
+        )
+
+    return comp

src/fenris/status_composition.py

@@ -0,0 +1,526 @@
+"""Shared status composition for TUI and CLI (issue #78, TPH-2/3).
+
+Centralizes the monitoring status lattice consumed by both surfaces.
+States: Monitoring, Collecting, Paused, Waiting, Interrupted, Error, Stale, Unknown.
+
+Precedence: Error > Interrupted > Paused > Stale > Waiting > Monitoring > Unknown.
+Collecting overlays every base except store fault.
+
+Freshness grading uses shared constants from status.py.
+"""
+import enum
+import sqlite3
+from dataclasses import dataclass, field
+from datetime import datetime, timedelta, timezone
+from typing import Any, Dict, List, Optional
+
+# Status poll interval (AC78-6): lightweight 5s systemctl show poll
+STATUS_POLL_INTERVAL_S = 5
+
+from .status import (
+    FRESH_THRESHOLD_S,
+    STALENESS_THRESHOLD_S,
+    grade_freshness,
+    freshness_age_human,
+    is_deliberately_paused,
+    monitoring_continuity,
+    deliberate_pause_lines,
+    open_store_readonly,
+    StoreFault,
+    NewerSchema,
+)
+
+
+# ---------------------------------------------------------------------------
+# Status state enum with glyph and label
+# ---------------------------------------------------------------------------
+
+class StatusState(enum.Enum):
+    """The eight monitoring status states (TPH-2)."""
+
+    MONITORING = "monitoring"
+    COLLECTING = "collecting"
+    PAUSED = "paused"
+    WAITING = "waiting"
+    INTERRUPTED = "interrupted"
+    ERROR = "error"
+    STALE = "stale"
+    UNKNOWN = "unknown"
+
+    @property
+    def glyph(self) -> str:
+        _glyphs = {
+            "monitoring": "●",
+            "collecting": "◐",
+            "paused": "‖",
+            "waiting": "○",
+            "interrupted": "⊘",
+            "error": "✖",
+            "stale": "◌",
+            "unknown": "?",
+        }
+        return _glyphs[self.value]
+
+    @property
+    def label(self) -> str:
+        return self.value.capitalize()
+
+
+# Precedence order: higher index = higher precedence
+_PRECEDENCE = [
+    StatusState.UNKNOWN,
+    StatusState.MONITORING,
+    StatusState.WAITING,
+    StatusState.STALE,
+    StatusState.PAUSED,
+    StatusState.INTERRUPTED,
+    StatusState.ERROR,
+]
+
+_PRECEDENCE_RANK = {s: i for i, s in enumerate(_PRECEDENCE)}
+
+
+# ---------------------------------------------------------------------------
+# Status composition result
+# ---------------------------------------------------------------------------
+
+@dataclass
+class StatusComposition:
+    """The composed status result shared between TUI and CLI."""
+
+    state: StatusState
+    glyph: str
+    label: str
+    explanation: str
+
+    # Separate facts (never folded into the status word)
+    freshness: str = "unknown"
+    freshness_age_s: Optional[int] = None
+    last_collect_ok: Optional[bool] = None
+    last_collect_age_s: Optional[int] = None
+    last_collect_reason: Optional[str] = None
+    boot_enabled: Optional[bool] = None
+    timer_active: Optional[bool] = None
+    deliberately_paused: bool = False
+    pause_age_s: Optional[int] = None
+    external_stop_reason: Optional[str] = None
+
+    # Store fault / newer schema (suppress store-dependent views)
+    store_fault: Optional[str] = None
+    newer_schema: Optional[str] = None
+
+    # Collecting overlay
+    overlay_base: Optional[StatusState] = None
+
+    # Sample counts for waiting explanations
+    sample_count: int = 0
+    day_count: int = 0
+
+    # Whether the status dot should blink (only Monitoring)
+    should_blink: bool = False
+
+    # Continuity line
+    continuity: str = ""
+
+    # Paused lines (for TUI banner)
+    paused_lines: List[str] = field(default_factory=list)
+
+
+# ---------------------------------------------------------------------------
+# Status composition logic
+# ---------------------------------------------------------------------------
+
+def _determine_base_state(
+    freshness: str,
+    sample_count: int,
+    day_count: int,
+    boot_enabled: Optional[bool],
+    timer_active: Optional[bool],
+    last_collect_ok: Optional[bool],
+    deliberately_paused: bool,
+    external_stop_reason: Optional[str],
+    service_available: bool,
+) -> StatusState:
+    """Determine the base status state from facts.
+
+    Precedence: Error > Interrupted > Paused > Stale > Waiting > Monitoring > Unknown.
+    """
+    # Unknown: service query failed and no store-derived fact places us higher
+    if not service_available:
+        return StatusState.UNKNOWN
+
+    # Error: last collect failed
+    if last_collect_ok is False:
+        return StatusState.ERROR
+
+    # Interrupted: external stop (not user_disabled)
+    if external_stop_reason is not None:
+        return StatusState.INTERRUPTED
+
+    # Paused: deliberate disable
+    if deliberately_paused:
+        return StatusState.PAUSED
+
+    # Stale: timer active, no failure, but data ≥ 48h old
+    if freshness == "stale" and timer_active and last_collect_ok is not False:
+        return StatusState.STALE
+
+    # Waiting: empty store, single sample, or fresh data but not yet enough evidence
+    if sample_count == 0:
+        return StatusState.WAITING
+    if sample_count <= 1 and day_count == 0:
+        return StatusState.WAITING
+
+    # Monitoring: everything is fine
+    return StatusState.MONITORING
+
+
+def _determine_explanation(
+    state: StatusState,
+    freshness: str,
+    freshness_age_s: Optional[int],
+    last_collect_ok: Optional[bool],
+    last_collect_reason: Optional[str],
+    sample_count: int,
+    deliberately_paused: bool,
+    store_fault: Optional[str],
+    newer_schema: Optional[str],
+) -> str:
+    """Determine the explanation line for the status state."""
+    if store_fault:
+        return "observation store unreadable — see journal"
+
+    if newer_schema:
+        return "observation store written by a newer Fenris — upgrade Fenris"
+
+    if state == StatusState.ERROR:
+        parts = []
+        if last_collect_ok is False:
+            parts.append("last run failed")
+            if last_collect_reason:
+                parts.append("(%s)" % last_collect_reason)
+        if freshness_age_s is not None and freshness != "empty":
+            parts.append("· last good sample %s ago" % freshness_age_human(freshness_age_s))
+        return " ".join(parts) if parts else "last run failed"
+
+    if state == StatusState.INTERRUPTED:
+        return "collection stopped outside Fenris — monitoring period still open"
+
+    if state == StatusState.PAUSED:
+        return "monitoring paused — paused time excluded from your usage habit"
+
+    if state == StatusState.STALE:
+        if freshness_age_s is not None:
+            return "last sample %s ago" % freshness_age_human(freshness_age_s)
+        return "data is stale"
+
+    if state == StatusState.WAITING:
+        if sample_count == 0:
+            return "awaiting first sample"
+        if sample_count <= 1:
+            return "awaiting another sample"
+        return "waiting for data"
+
+    if state == StatusState.MONITORING:
+        if freshness_age_s is not None:
+            return "last sample %s ago" % freshness_age_human(freshness_age_s)
+        return "monitoring active"
+
+    if state == StatusState.UNKNOWN:
+        return "service state unavailable"
+
+    return ""
+
+
+def _determine_collecting_overlay(
+    base_state: StatusState,
+    last_collect_ok: Optional[bool],
+    deliberately_paused: bool,
+    store_fault: Optional[str],
+    newer_schema: Optional[str],
+) -> str:
+    """Determine the explanation line when Collecting overlays a base state."""
+    if store_fault or newer_schema:
+        return "run in flight — store fault"
+
+    if base_state == StatusState.PAUSED:
+        return "run in flight — paused"
+    if base_state == StatusState.INTERRUPTED:
+        return "run in flight — interrupted"
+    if base_state == StatusState.ERROR:
+        return "run in flight — retry"
+    if base_state == StatusState.STALE:
+        return "run in flight — stale data"
+    if base_state == StatusState.WAITING:
+        return "run in flight"
+    return "run in flight"
+
+
+def compose_status(
+    conn: sqlite3.Connection,
+    service: Optional[Dict[str, Any]],
+    clock_now: datetime,
+    store_fault: Optional[str] = None,
+    newer_schema: Optional[str] = None,
+    collecting: bool = False,
+    reduced_motion: bool = False,
+) -> StatusComposition:
+    """Compose the shared status from service state and store data.
+
+    This is the single entry point consumed by both TUI and CLI.
+    """
+    service_available = service is not None and len(service) > 0
+
+    # --- Separate facts from service ---
+    boot_enabled = service.get("boot_enabled") if service_available else None
+    timer_active = service.get("timer_active") if service_available else None
+    last_collect_ok = service.get("last_collect_ok") if service_available else None
+    last_collect_age_s = service.get("last_collect_age_s") if service_available else None
+    last_collect_reason = service.get("last_collect_reason") if service_available else None
+
+    # --- Freshness from store ---
+    freshness = "unknown"
+    freshness_age_s = None
+    sample_count = 0
+    day_count = 0
+    deliberately_paused = False
+
+    if store_fault is None and newer_schema is None:
+        try:
+            cursor = conn.execute("SELECT ts FROM samples ORDER BY id DESC LIMIT 1")
+            row = cursor.fetchone()
+            newest_ts = row[0] if row else None
+            freshness = grade_freshness(newest_ts, clock_now)
+            if newest_ts:
+                try:
+                    ts = datetime.fromisoformat(newest_ts)
+                    if ts.tzinfo is None:
+                        ts = ts.replace(tzinfo=timezone.utc)
+                    else:
+                        ts = ts.astimezone(timezone.utc)
+                    freshness_age_s = int((clock_now - ts).total_seconds())
+                except (ValueError, TypeError):
+                    pass
+        except sqlite3.Error:
+            freshness = "unknown"
+
+        try:
+            cursor = conn.execute("SELECT COUNT(*) FROM samples")
+            sample_count = cursor.fetchone()[0]
+            cursor = conn.execute("SELECT COUNT(*) FROM day_aggregates")
+            day_count = cursor.fetchone()[0]
+        except sqlite3.Error:
+            pass
+
+        try:
+            svc_for_pause = service if service_available else {}
+            deliberately_paused = is_deliberately_paused(conn, svc_for_pause)
+        except sqlite3.Error:
+            deliberately_paused = False
+
+    # --- External stop detection ---
+    # External stop = timer inactive + boot disabled + NOT deliberately paused
+    # + period still open (the timer was stopped but Fenris didn't close the period)
+    external_stop_reason = None
+    if not deliberately_paused and timer_active is False and boot_enabled is False:
+        # Check if there's an open monitoring period (external stop left it open)
+        try:
+            open_period = conn.execute(
+                "SELECT 1 FROM monitoring_periods WHERE ended_at IS NULL LIMIT 1"
+            ).fetchone()
+            if open_period is not None:
+                external_stop_reason = "external_stop"
+        except sqlite3.Error:
+            pass
+
+    # --- Determine base state ---
+    # Store fault and newer schema always override to ERROR
+    if store_fault is not None or newer_schema is not None:
+        base_state = StatusState.ERROR
+    else:
+        base_state = _determine_base_state(
+            freshness=freshness,
+            sample_count=sample_count,
+            day_count=day_count,
+            boot_enabled=boot_enabled,
+            timer_active=timer_active,
+            last_collect_ok=last_collect_ok,
+            deliberately_paused=deliberately_paused,
+            external_stop_reason=external_stop_reason,
+            service_available=service_available,
+        )
+
+    # --- Apply Collecting overlay ---
+    state = base_state
+    overlay_base = None
+    explanation = ""
+
+    if collecting and store_fault is None and newer_schema is None:
+        # Collecting overlays every base except store fault
+        overlay_base = base_state
+        state = StatusState.COLLECTING
+        explanation = _determine_collecting_overlay(
+            base_state, last_collect_ok, deliberately_paused,
+            store_fault, newer_schema,
+        )
+    else:
+        explanation = _determine_explanation(
+            base_state, freshness, freshness_age_s,
+            last_collect_ok, last_collect_reason,
+            sample_count, deliberately_paused,
+            store_fault, newer_schema,
+        )
+
+    # --- Continuity line ---
+    continuity = ""
+    if service_available:
+        continuity = monitoring_continuity(service)
+
+    # --- Paused lines ---
+    paused_lines = []
+    if deliberately_paused:
+        paused_lines = deliberate_pause_lines()
+
+    # Determine blink flag: only Monitoring dot blinks, never text or other states
+    should_blink = (state == StatusState.MONITORING and not reduced_motion)
+
+    return StatusComposition(
+        state=state,
+        glyph=state.glyph,
+        label=state.label,
+        explanation=explanation,
+        should_blink=should_blink,
+        freshness=freshness,
+        freshness_age_s=freshness_age_s,
+        last_collect_ok=last_collect_ok,
+        last_collect_age_s=last_collect_age_s,
+        last_collect_reason=last_collect_reason,
+        boot_enabled=boot_enabled,
+        timer_active=timer_active,
+        deliberately_paused=deliberately_paused,
+        external_stop_reason=external_stop_reason,
+        store_fault=store_fault,
+        newer_schema=newer_schema,
+        overlay_base=overlay_base,
+        sample_count=sample_count,
+        day_count=day_count,
+        continuity=continuity,
+        paused_lines=paused_lines,
+    )
+
+
+# ---------------------------------------------------------------------------
+# CLI rendering (static, no styling)
+# ---------------------------------------------------------------------------
+
+def render_status_cli(comp: StatusComposition) -> str:
+    """Render the status composition as static CLI text."""
+    lines = []
+
+    # Status line
+    lines.append("%s %s" % (comp.glyph, comp.label))
+
+    # Explanation
+    if comp.explanation:
+        lines.append(comp.explanation)
+
+    lines.append("")
+
+    # Separate facts
+    facts = []
+    if comp.freshness != "unknown":
+        facts.append("freshness: %s" % comp.freshness)
+    if comp.freshness_age_s is not None:
+        facts[-1] += " (%s)" % freshness_age_human(comp.freshness_age_s) if facts else "freshness: %s" % freshness_age_human(comp.freshness_age_s)
+    if comp.last_collect_ok is True:
+        facts.append("last collect: ok")
+    elif comp.last_collect_ok is False:
+        collect_str = "last collect: FAILED"
+        if comp.last_collect_reason:
+            collect_str += " (%s)" % comp.last_collect_reason
+        facts.append(collect_str)
+    else:
+        facts.append("last collect: unknown")
+    if comp.boot_enabled is not None:
+        facts.append("boot: %s" % ("enabled" if comp.boot_enabled else "disabled"))
+    if comp.timer_active is not None:
+        facts.append("timer: %s" % ("active" if comp.timer_active else "inactive"))
+
+    if facts:
+        lines.append(" · ".join(facts))
+
+    # Continuity
+    if comp.continuity:
+        lines.append("")
+        lines.append("CONTINUITY: %s" % comp.continuity)
+
+    # Deliberate pause
+    if comp.paused_lines:
+        for pl in comp.paused_lines:
+            lines.append(pl)
+
+    return "\n".join(lines)
+
+
+# ---------------------------------------------------------------------------
+# TUI rendering (with styling tokens)
+# ---------------------------------------------------------------------------
+
+def render_status_tui(comp: StatusComposition) -> str:
+    """Render the status composition as TUI text with Textual markup."""
+    lines = []
+
+    # Status line with color
+    color = {
+        StatusState.MONITORING: "green",
+        StatusState.COLLECTING: "green",
+        StatusState.PAUSED: "yellow",
+        StatusState.WAITING: "yellow",
+        StatusState.INTERRUPTED: "red",
+        StatusState.ERROR: "red",
+        StatusState.STALE: "red",
+        StatusState.UNKNOWN: "dim",
+    }[comp.state]
+
+    lines.append("[%s]%s %s[/%s]" % (color, comp.glyph, comp.label, color))
+
+    # Explanation
+    if comp.explanation:
+        lines.append(comp.explanation)
+
+    lines.append("")
+
+    # Separate facts
+    facts = []
+    if comp.freshness != "unknown":
+        facts.append("freshness: %s" % comp.freshness)
+    if comp.freshness_age_s is not None and facts:
+        facts[-1] += " (%s)" % freshness_age_human(comp.freshness_age_s)
+    if comp.last_collect_ok is True:
+        facts.append("last collect: ok")
+    elif comp.last_collect_ok is False:
+        collect_str = "last collect: FAILED"
+        if comp.last_collect_reason:
+            collect_str += " (%s)" % comp.last_collect_reason
+        facts.append(collect_str)
+    else:
+        facts.append("last collect: unknown")
+    if comp.boot_enabled is not None:
+        facts.append("boot: %s" % ("enabled" if comp.boot_enabled else "disabled"))
+    if comp.timer_active is not None:
+        facts.append("timer: %s" % ("active" if comp.timer_active else "inactive"))
+
+    if facts:
+        lines.append(" · ".join(facts))
+
+    # Continuity
+    if comp.continuity:
+        lines.append("")
+        lines.append("[bold]CONTINUITY[/bold]  %s" % comp.continuity)
+
+    # Deliberate pause
+    if comp.paused_lines:
+        for pl in comp.paused_lines:
+            lines.append(pl)
+
+    return "\n".join(lines)

src/fenris/store.py

@@ -0,0 +1,286 @@
+"""Observation store: SQLite database for persisting observation history.
+
+This module handles:
+- Store initialization with WAL mode
+- Schema versioning with PRAGMA user_version
+- The six entities: samples, hour_observations, day_aggregates,
+  monitoring_periods, controller_segments, endurance_baseline
+"""
+import sqlite3
+from pathlib import Path
+from typing import Optional
+
+
+# Schema version - increment on each migration
+SCHEMA_VERSION = 2
+
+
+# Packaged default placement (spec §8.3). The config may override it, but a
+# fresh install that sets only the device selector must collect cleanly.
+DEFAULT_STORE_PATH = Path("/var/lib/fenris/observations.db")
+
+
+def get_store_path(config: dict) -> Path:
+    """Get the store path from config.
+
+    Falls back to the packaged default when the config does not pin one,
+    so a fresh install whose config holds only the device selector works
+    instead of crashing with KeyError 'store_path' (issue #53).
+    """
+    return Path(config.get("store_path", DEFAULT_STORE_PATH))
+
+
+def init_store(store_path: Path) -> sqlite3.Connection:
+    """Initialize the observation store if not present.
+    
+    Creates the database with WAL mode and all six entities.
+    Returns a connection to the store.
+    """
+    conn = sqlite3.connect(str(store_path))
+
+    # Enable WAL mode for concurrent reads during writes
+    conn.execute("PRAGMA journal_mode=WAL")
+
+    # Group members (fenris group) read the live store read-only, but SQLite
+    # in WAL mode needs write access to the db and its -wal/-shm sidecars even
+    # for readers. Best effort: root-created stores stay group-accessible
+    # without relying on the creating process's umask (issue #54).
+    import os as _os
+    for sidecar in (store_path,
+                    store_path.with_name(store_path.name + "-wal"),
+                    store_path.with_name(store_path.name + "-shm")):
+        try:
+            mode = _os.stat(sidecar).st_mode & 0o777
+            _os.chmod(sidecar, mode | 0o060)
+        except OSError:
+            pass
+
+    # Check if this is a new database
+    cursor = conn.execute("PRAGMA user_version")
+    current_version = cursor.fetchone()[0]
+    
+    if current_version == 0:
+        # New database - create schema
+        _create_schema(conn)
+        conn.execute(f"PRAGMA user_version={SCHEMA_VERSION}")
+        conn.commit()
+    elif current_version > SCHEMA_VERSION:
+        # Unknown newer version - refuse
+        conn.close()
+        raise ValueError(
+            f"Observation store written by a newer Fenris (version {current_version}) "
+            f"— upgrade Fenris"
+        )
+    elif current_version < SCHEMA_VERSION:
+        # Older version - apply migrations
+        _apply_migrations(conn, current_version)
+        conn.execute(f"PRAGMA user_version={SCHEMA_VERSION}")
+        conn.commit()
+    
+    return conn
+
+
+def _create_schema(conn: sqlite3.Connection):
+    """Create the initial schema with all six entities."""
+    
+    # Samples: raw collection runs (14-day retention)
+    conn.execute("""
+        CREATE TABLE IF NOT EXISTS samples (
+            id INTEGER PRIMARY KEY AUTOINCREMENT,
+            ts TEXT NOT NULL,  -- ISO 8601 UTC timestamp
+            device TEXT NOT NULL,
+            -- Normalized controller-identity fields captured at acquisition
+            subnqn TEXT,
+            sn TEXT,
+            mn TEXT,
+            fr TEXT,
+            capacity_bytes INTEGER,
+            percentage_used INTEGER,
+            available_spare INTEGER,
+            media_errors INTEGER,
+            power_on_hours INTEGER,
+            power_cycles INTEGER,
+            unsafe_shutdowns INTEGER,
+            temperature_c INTEGER,
+            data_units_written INTEGER,
+            data_units_read INTEGER,
+            bytes_written INTEGER,
+            bytes_read INTEGER,
+            critical_warning INTEGER,
+            segment_id INTEGER
+        )
+    """)
+    
+    # Hour observations: UTC-hour usage-habit split
+    conn.execute("""
+        CREATE TABLE IF NOT EXISTS hour_observations (
+            id INTEGER PRIMARY KEY AUTOINCREMENT,
+            hour TEXT NOT NULL UNIQUE,  -- ISO 8601 UTC hour (e.g., "2026-09-01T12:00:00Z")
+            active_seconds INTEGER DEFAULT 0,
+            idle_seconds INTEGER DEFAULT 0,
+            powered_off_seconds INTEGER DEFAULT 0,
+            unknown_seconds INTEGER DEFAULT 0,
+            bytes_written_delta INTEGER DEFAULT 0,
+            bytes_read_delta INTEGER DEFAULT 0,
+            temperature_min INTEGER,
+            temperature_avg REAL,
+            temperature_max INTEGER,
+            sample_count INTEGER DEFAULT 0,
+            coverage REAL DEFAULT 0.0
+        )
+    """)
+    
+    # Day aggregates: derived from hour observations
+    conn.execute("""
+        CREATE TABLE IF NOT EXISTS day_aggregates (
+            id INTEGER PRIMARY KEY AUTOINCREMENT,
+            day TEXT NOT NULL UNIQUE,  -- ISO 8601 UTC day (e.g., "2026-09-01")
+            active_seconds INTEGER DEFAULT 0,
+            idle_seconds INTEGER DEFAULT 0,
+            powered_off_seconds INTEGER DEFAULT 0,
+            unknown_seconds INTEGER DEFAULT 0,
+            bytes_written_delta INTEGER DEFAULT 0,
+            bytes_read_delta INTEGER DEFAULT 0,
+            sample_count INTEGER DEFAULT 0,
+            coverage REAL DEFAULT 0.0,
+            unattributed_bytes_written INTEGER DEFAULT 0,
+            unattributed_bytes_read INTEGER DEFAULT 0
+        )
+    """)
+    
+    # Monitoring periods: tracking when monitoring was enabled/disabled
+    conn.execute("""
+        CREATE TABLE IF NOT EXISTS monitoring_periods (
+            id INTEGER PRIMARY KEY AUTOINCREMENT,
+            started_at TEXT NOT NULL,  -- ISO 8601 UTC timestamp
+            ended_at TEXT,  -- NULL if currently active
+            end_cause TEXT CHECK(end_cause IN ('user_disabled', 'migrated', 'unknown_gap'))
+        )
+    """)
+    
+    # Controller segments: identity key plus metadata snapshot
+    conn.execute("""
+        CREATE TABLE IF NOT EXISTS controller_segments (
+            id INTEGER PRIMARY KEY AUTOINCREMENT,
+            opened_at TEXT NOT NULL,  -- ISO 8601 UTC timestamp
+            identity_key TEXT,  -- Normalized identity key (NULL if degraded)
+            identity_degraded BOOLEAN DEFAULT 0,
+            subnqn TEXT,
+            sn TEXT,
+            mn TEXT,
+            fr TEXT,
+            vid TEXT,
+            ssvid TEXT,
+            transport TEXT
+        )
+    """)
+    
+    # Endurance baseline: one active row, replaced on edit
+    conn.execute("""
+        CREATE TABLE IF NOT EXISTS endurance_baseline (
+            id INTEGER PRIMARY KEY AUTOINCREMENT,
+            tbw_terabytes REAL NOT NULL,
+            source_url TEXT,
+            document_revision TEXT,
+            entry_date TEXT,
+            model_string TEXT,
+            nominal_capacity_bytes INTEGER,
+            validated_by TEXT,  -- 'user' or 'machine_match'
+            verified BOOLEAN DEFAULT 0,
+            created_at TEXT NOT NULL,
+            updated_at TEXT NOT NULL
+        )
+    """)
+
+
+    # Metadata table for store state (e.g., legacy import marker)
+    conn.execute("""
+        CREATE TABLE IF NOT EXISTS store_metadata (
+            key TEXT PRIMARY KEY,
+            value TEXT NOT NULL
+        )
+    """)
+
+
+def _apply_migrations(conn: sqlite3.Connection, current_version: int):
+    """Apply forward-only migrations from current_version to SCHEMA_VERSION.
+    
+    Each migration step is a transactional block. Add new steps as sequential
+    elif branches when SCHEMA_VERSION increases.
+    
+    Spec: §3.6, §10.2
+    """
+    # Migration 1→2: add segment_id provenance to samples,
+    # unattributed byte tracking to day_aggregates (issue #73)
+    if current_version < 2:
+        # Defensive: only ALTER if table exists (handles minimal v1 stores)
+        tables = {row[0] for row in conn.execute(
+            "SELECT name FROM sqlite_master WHERE type='table'"
+        ).fetchall()}
+        if "samples" in tables:
+            # Check if column already exists (idempotent)
+            cols = {row[1] for row in conn.execute("PRAGMA table_info(samples)").fetchall()}
+            if "segment_id" not in cols:
+                conn.execute("ALTER TABLE samples ADD COLUMN segment_id INTEGER")
+        if "day_aggregates" in tables:
+            cols = {row[1] for row in conn.execute("PRAGMA table_info(day_aggregates)").fetchall()}
+            if "unattributed_bytes_written" not in cols:
+                conn.execute("ALTER TABLE day_aggregates ADD COLUMN unattributed_bytes_written INTEGER DEFAULT 0")
+            if "unattributed_bytes_read" not in cols:
+                conn.execute("ALTER TABLE day_aggregates ADD COLUMN unattributed_bytes_read INTEGER DEFAULT 0")
+        current_version = 2
+
+
+def migrate_to_latest(store_path: Path) -> int:
+    """Apply forward-only migrations to bring the store to SCHEMA_VERSION.
+    
+    Called by the upgrade target (§10.2). Returns the number of migration
+    steps applied. Raises ValueError on newer-schema store (§3.6, §9.5).
+    
+    Spec: §3.6, §10.2, §10.3
+    """
+    conn = sqlite3.connect(str(store_path))
+    conn.execute("PRAGMA journal_mode=WAL")
+    
+    cursor = conn.execute("PRAGMA user_version")
+    current_version = cursor.fetchone()[0]
+    
+    if current_version > SCHEMA_VERSION:
+        conn.close()
+        raise ValueError(
+            f"Observation store written by a newer Fenris (version {current_version}) "
+            f"— upgrade Fenris"
+        )
+    
+    if current_version == SCHEMA_VERSION:
+        conn.close()
+        return 0  # Already up to date
+    
+    # Version 0 means no schema — create fresh (issue #73)
+    if current_version == 0:
+        _create_schema(conn)
+        conn.execute(f"PRAGMA user_version={SCHEMA_VERSION}")
+        conn.commit()
+        conn.close()
+        return SCHEMA_VERSION
+    
+    steps = SCHEMA_VERSION - current_version
+    _apply_migrations(conn, current_version)
+    conn.execute(f"PRAGMA user_version={SCHEMA_VERSION}")
+    conn.commit()
+    conn.close()
+    return steps
+
+
+def is_store_faulty(store_path: Path) -> bool:
+    """Check if the store is present but cannot be read or trusted."""
+    if not store_path.exists():
+        return False
+    
+    try:
+        conn = sqlite3.connect(f"file:{store_path}?mode=ro", uri=True)
+        conn.execute("PRAGMA user_version")
+        conn.close()
+        return False
+    except sqlite3.Error:
+        return True

src/fenris/themes.py

@@ -0,0 +1,161 @@
+"""Fenris theme presets (issue #80).
+
+Three accessible colour presets: Amber (default), Nord, and High Contrast.
+Themes style chrome, borders, accents, muted text, and graph roles;
+status semantic colours/glyphs/text always win.
+
+Theme roles for graph rendering expose distinct colours per preset so
+the bar graph can reflect the user's visual preference without depending
+on graph-ticket completion.
+
+Criteria: TPH-10, AC80-1, AC80-5.
+"""
+from typing import Dict
+
+from textual.theme import Theme
+
+
+# ---------------------------------------------------------------------------
+# Status semantic colours — always win, never themed (AC80-1)
+# ---------------------------------------------------------------------------
+
+STATUS_COLORS = {
+    "monitoring": "green",
+    "collecting": "green",
+    "paused": "yellow",
+    "waiting": "yellow",
+    "interrupted": "red",
+    "error": "red",
+    "stale": "red",
+    "unknown": "dim",
+}
+
+
+# ---------------------------------------------------------------------------
+# Amber theme — warm golden tones (default, amber graph role)
+# ---------------------------------------------------------------------------
+
+_AMBER = Theme(
+    name="fenris-amber",
+    primary="#d4a017",       # warm amber
+    secondary="#c49b0a",     # darker amber
+    accent="#ffd54f",        # light amber highlight
+    warning="#e6a817",       # amber warning
+    error="#e74c3c",         # red error
+    success="#27ae60",       # green success
+    foreground="#e8e0d0",    # warm light
+    background="#1a1510",    # warm dark
+    surface="#241f16",       # warm surface
+    panel="#2a2318",         # warm panel
+    boost="#332a1c",         # warm boost
+    dark=True,
+    variables={
+        "graph-allocated": "#d4a017",
+        "graph-unallocated": "#8b6914",
+        "graph-gap": "#554422",
+        "graph-zero": "#665533",
+        "graph-partial": "#aa8822",
+        "graph-selection": "#ffd54f",
+        "border-default": "#554422",
+        "muted-text": "#887755",
+    },
+)
+
+# ---------------------------------------------------------------------------
+# Nord theme — cool blue-gray polar night palette
+# ---------------------------------------------------------------------------
+
+_NORD = Theme(
+    name="fenris-nord",
+    primary="#88c0d0",       # nord8 frost
+    secondary="#81a1c1",     # nord9
+    accent="#8fbcbb",        # nord7
+    warning="#ebcb8b",       # nord13
+    error="#bf616a",         # nord11
+    success="#a3be8c",       # nord14
+    foreground="#eceff4",    # nord6
+    background="#2e3440",    # nord0
+    surface="#3b4252",       # nord1
+    panel="#434c5e",         # nord2
+    boost="#4c566a",         # nord3
+    dark=True,
+    variables={
+        "graph-allocated": "#88c0d0",
+        "graph-unallocated": "#5e81ac",
+        "graph-gap": "#4c566a",
+        "graph-zero": "#616e88",
+        "graph-partial": "#81a1c1",
+        "graph-selection": "#8fbcbb",
+        "border-default": "#4c566a",
+        "muted-text": "#7b88a1",
+    },
+)
+
+# ---------------------------------------------------------------------------
+# High Contrast — maximum readability, pure black and white
+# ---------------------------------------------------------------------------
+
+_HIGH_CONTRAST = Theme(
+    name="fenris-high-contrast",
+    primary="#ffffff",       # pure white
+    secondary="#dddddd",     # light gray
+    accent="#ffff00",        # bright yellow
+    warning="#ff8800",       # bright orange
+    error="#ff0000",         # pure red
+    success="#00ff00",       # pure green
+    foreground="#ffffff",    # pure white
+    background="#000000",    # pure black
+    surface="#111111",       # near-black surface
+    panel="#1a1a1a",         # near-black panel
+    boost="#222222",         # near-black boost
+    dark=True,
+    variables={
+        "graph-allocated": "#ffffff",
+        "graph-unallocated": "#aaaaaa",
+        "graph-gap": "#555555",
+        "graph-zero": "#666666",
+        "graph-partial": "#cccccc",
+        "graph-selection": "#ffff00",
+        "border-default": "#ffffff",
+        "muted-text": "#aaaaaa",
+    },
+)
+
+
+# ---------------------------------------------------------------------------
+# Theme registry
+# ---------------------------------------------------------------------------
+
+THEMES = {
+    "amber": _AMBER,
+    "nord": _NORD,
+    "high_contrast": _HIGH_CONTRAST,
+}
+
+THEME_NAMES = set(THEMES.keys())
+
+
+def get_theme(name: str) -> Theme:
+    """Return a registered theme by preset name.
+
+    Unknown names fall back to Amber.
+    """
+    return THEMES.get(name, _AMBER)
+
+
+def get_graph_colors(theme_name: str) -> Dict[str, str]:
+    """Return the graph colour roles for a theme preset.
+
+    Returns a dict with keys: allocated, unallocated, gap, zero, partial,
+    selection.  Falls back to Amber for unknown names.
+    """
+    theme = get_theme(theme_name)
+    variables = theme.variables or {}
+    return {
+        "allocated": variables.get("graph-allocated", "#d4a017"),
+        "unallocated": variables.get("graph-unallocated", "#8b6914"),
+        "gap": variables.get("graph-gap", "#554422"),
+        "zero": variables.get("graph-zero", "#665533"),
+        "partial": variables.get("graph-partial", "#aa8822"),
+        "selection": variables.get("graph-selection", "#ffd54f"),
+    }

tests/conftest.py

@@ -0,0 +1,20 @@
+"""Shared test helpers for Fenris test suite."""
+from pathlib import Path
+
+import pytest
+
+REPO_ROOT = Path(__file__).resolve().parent.parent
+VERSION_FILE = REPO_ROOT / "pyproject.toml"
+
+
+def get_version() -> str:
+    """Extract version from pyproject.toml."""
+    for line in VERSION_FILE.read_text().splitlines():
+        if line.startswith("version"):
+            return line.split("=")[1].strip().strip('"')
+    raise RuntimeError("Could not determine version from pyproject.toml")
+
+
+def read(path: str | Path) -> str:
+    """Read a file relative to the repository root."""
+    return (REPO_ROOT / path).read_text()

tests/test_acceptance_sweep.py

@@ -0,0 +1,749 @@
+"""Cross-cutting acceptance sweep (issue #32).
+
+Systematic verification of every acceptance criterion that spans multiple
+subsystems.  Grouped by criterion ID; each test cites its clause.
+
+CI-1  Exhaustive state matrix: confidence × freshness × baseline tier
+CI-2  TUI/CLI parity: identical outcomes and wording
+CI-3  Prohibition set: automated structural checks
+CI-4  Required wording and six disclosures in both views
+"""
+import re
+import sqlite3
+from datetime import datetime, timedelta, timezone
+from pathlib import Path
+from unittest.mock import patch
+
+import pytest
+import sys
+
+sys.path.insert(0, str(Path(__file__).parent.parent / "src"))
+
+from fenris.store import init_store, SCHEMA_VERSION
+from fenris.monitoring_periods import ensure_period_open
+from fenris.projection import (
+    compute_projection,
+    ConfidenceState,
+    BaselineTier,
+    DISCLOSURES,
+    STALENESS_HOURS,
+    WARMING_MIN_DAYS,
+    YOUNG_REGIME_DAYS,
+)
+from fenris.status import (
+    grade_freshness,
+    get_status,
+    render_status,
+    format_disclosures,
+    FRESH_THRESHOLD_S,
+    STALENESS_THRESHOLD_S,
+    CADENCE_DEFAULT_S,
+    ACCURACY_SEC,
+)
+from fenris.tui import (
+    FenrisTuiApp,
+    _format_remaining,
+)
+
+
+SRC_DIR = Path(__file__).parent.parent / "src"
+FENRIS_PKG = SRC_DIR / "fenris"
+
+
+def _clock(year=2026, month=9, day=30, hour=12):
+    return datetime(year, month, day, hour, 0, 0, tzinfo=timezone.utc)
+
+
+def _insert_baseline(conn, tbw_tb=1.0, verified=True,
+                      model="Samsung SSD 970 EVO Plus 1TB",
+                      source_url="https://example.com/spec",
+                      doc_rev="v1.0", entry_date="2026-01-01",
+                      nominal_cap=1024000000000):
+    conn.execute(
+        "INSERT INTO endurance_baseline "
+        "(tbw_terabytes, source_url, document_revision, entry_date, model_string, "
+        " nominal_capacity_bytes, validated_by, verified, created_at, updated_at) "
+        "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)",
+        (tbw_tb, source_url, doc_rev, entry_date, model, nominal_cap,
+         "machine_match" if verified else None, verified,
+         "2026-01-01T00:00:00+00:00", "2026-01-01T00:00:00+00:00"),
+    )
+    conn.commit()
+
+
+def _insert_segment(conn, opened_at="2026-09-01T00:00:00+00:00",
+                     identity_key="nqn.test", degraded=False,
+                     mn="Samsung SSD 970 EVO Plus 1TB"):
+    conn.execute(
+        "INSERT INTO controller_segments "
+        "(opened_at, identity_key, identity_degraded, subnqn, sn, mn, fr, vid, ssvid, transport) "
+        "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)",
+        (opened_at, identity_key, degraded, "nqn.test", "SN123", mn, "FW1",
+         "0x144d", "0x144d", "pcie"),
+    )
+    conn.commit()
+
+
+def _insert_day(conn, day, bw=1024*1024*100, coverage=0.95, samples=24):
+    conn.execute(
+        "INSERT INTO day_aggregates (day, active_seconds, idle_seconds, "
+        "powered_off_seconds, unknown_seconds, bytes_written_delta, "
+        "bytes_read_delta, sample_count, coverage) "
+        "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)",
+        (day, 3600, 0, 0, 0, bw, 0, samples, coverage),
+    )
+    conn.commit()
+
+
+def _insert_sample(conn, ts, pu=5):
+    conn.execute(
+        "INSERT INTO samples (ts, device, data_units_written, data_units_read, "
+        "percentage_used, bytes_written, bytes_read, power_on_hours) "
+        "VALUES (?, ?, ?, ?, ?, ?, ?, ?)",
+        (ts, "/dev/nvme0n1", 1000000, 500000, pu, 512000000000, 256000000000, 8765),
+    )
+    conn.commit()
+
+
+def _open_period(conn, start="2026-09-01T00:00:00+00:00"):
+    ensure_period_open(conn, datetime.fromisoformat(start))
+
+
+def _setup_full_store(conn, *, baseline=True, segment=True, days=30,
+                       bw=1024*1024*100, coverage=0.95, samples_per_day=24,
+                       sample_ts="2026-09-30T10:00:00+00:00",
+                       period_start="2026-09-01T00:00:00+00:00",
+                       segment_opened="2026-09-01T00:00:00+00:00",
+                       baseline_kw=None, segment_kw=None):
+    if baseline:
+        _insert_baseline(conn, **(baseline_kw or {}))
+    if segment:
+        _insert_segment(conn, opened_at=segment_opened, **(segment_kw or {}))
+    _open_period(conn, start=period_start)
+    for i in range(days):
+        d = (datetime(2026, 9, 1) + timedelta(days=i)).strftime("%Y-%m-%d")
+        _insert_day(conn, d, bw=bw, coverage=coverage, samples=samples_per_day)
+    if sample_ts:
+        _insert_sample(conn, sample_ts)
+
+
+# ===================================================================
+# CI-1: Exhaustive state matrix
+# ===================================================================
+
+
+class TestCI1StateMatrix:
+    """Systematic walk of confidence x freshness x baseline tier combinations."""
+
+    def test_no_baseline_unavailable(self, tmp_path):
+        conn = init_store(tmp_path / "db")
+        _insert_segment(conn)
+        _open_period(conn)
+        for i in range(30):
+            d = (datetime(2026, 9, 1) + timedelta(days=i)).strftime("%Y-%m-%d")
+            _insert_day(conn, d, bw=1024*1024*100, coverage=0.95, samples=24)
+        _insert_sample(conn, "2026-09-30T10:00:00+00:00")
+        proj = compute_projection(conn, _clock())
+        assert proj.confidence_state == ConfidenceState.UNSUPPORTED
+        assert proj.headline_remaining_seconds is None
+        assert proj.baseline_tier == BaselineTier.NONE
+        conn.close()
+
+    def test_verified_baseline_possible_supported(self, tmp_path):
+        conn = init_store(tmp_path / "db")
+        _setup_full_store(conn, baseline_kw=dict(tbw_tb=10.0, verified=True))
+        proj = compute_projection(conn, _clock())
+        assert proj.confidence_state == ConfidenceState.SUPPORTED
+        assert proj.baseline_tier == BaselineTier.VERIFIED
+        assert proj.headline_remaining_seconds is not None
+        conn.close()
+
+    def test_unverified_baseline_possible_limited(self, tmp_path):
+        conn = init_store(tmp_path / "db")
+        _setup_full_store(conn, baseline_kw=dict(
+            tbw_tb=10.0, verified=False, source_url=None))
+        proj = compute_projection(conn, _clock())
+        assert proj.baseline_tier == BaselineTier.UNVERIFIED
+        assert proj.confidence_state != ConfidenceState.SUPPORTED
+        conn.close()
+
+    def test_model_mismatch_unavailable(self, tmp_path):
+        conn = init_store(tmp_path / "db")
+        _setup_full_store(conn, baseline_kw=dict(model="Different Model"))
+        proj = compute_projection(conn, _clock())
+        assert proj.confidence_state == ConfidenceState.UNSUPPORTED
+        assert proj.baseline_tier == BaselineTier.NONE
+        conn.close()
+
+    def test_fresh_sample_grades_fresh(self, tmp_path):
+        now = _clock()
+        ts = (now - timedelta(seconds=FRESH_THRESHOLD_S - 10)).isoformat()
+        assert grade_freshness(ts, now) == "fresh"
+
+    def test_missed_sample_grades_missed(self, tmp_path):
+        now = _clock()
+        ts = (now - timedelta(hours=2)).isoformat()
+        assert grade_freshness(ts, now) == "missed"
+
+    def test_stale_sample_grades_stale(self, tmp_path):
+        now = _clock()
+        ts = (now - timedelta(hours=49)).isoformat()
+        assert grade_freshness(ts, now) == "stale"
+
+    def test_empty_store_grades_empty(self, tmp_path):
+        now = _clock()
+        assert grade_freshness(None, now) == "empty"
+
+    def test_unsupported_fresh(self, tmp_path):
+        conn = init_store(tmp_path / "db")
+        _insert_segment(conn)
+        _open_period(conn)
+        for i in range(20):
+            d = (datetime(2026, 9, 10) + timedelta(days=i)).strftime("%Y-%m-%d")
+            _insert_day(conn, d, bw=1024*1024*100)
+        fresh_ts = (_clock() - timedelta(seconds=60)).isoformat()
+        _insert_sample(conn, fresh_ts)
+        proj = compute_projection(conn, _clock())
+        assert proj.confidence_state == ConfidenceState.UNSUPPORTED
+        assert grade_freshness(fresh_ts, _clock()) == "fresh"
+        conn.close()
+
+    def test_limited_young_regime(self, tmp_path):
+        conn = init_store(tmp_path / "db")
+        _insert_baseline(conn, tbw_tb=10.0, verified=True)
+        _insert_segment(conn)
+        _open_period(conn)
+        for i in range(5):
+            d = (datetime(2026, 9, 25) + timedelta(days=i)).strftime("%Y-%m-%d")
+            _insert_day(conn, d, bw=1024*1024*100)
+        _insert_sample(conn, "2026-09-30T10:00:00+00:00")
+        proj = compute_projection(conn, _clock())
+        assert proj.confidence_state == ConfidenceState.LIMITED
+        conn.close()
+
+    def test_limited_warming(self, tmp_path):
+        conn = init_store(tmp_path / "db")
+        _insert_baseline(conn, tbw_tb=10.0, verified=True)
+        _insert_segment(conn)
+        _open_period(conn)
+        for i in range(10):
+            d = (datetime(2026, 9, 20) + timedelta(days=i)).strftime("%Y-%m-%d")
+            _insert_day(conn, d, bw=1024*1024*100, coverage=0.95, samples=24)
+        _insert_sample(conn, "2026-09-30T10:00:00+00:00")
+        proj = compute_projection(conn, _clock())
+        assert proj.confidence_state == ConfidenceState.LIMITED
+        assert proj.warming_fact is not None
+        conn.close()
+
+    def test_limited_stale_data(self, tmp_path):
+        conn = init_store(tmp_path / "db")
+        _insert_baseline(conn, tbw_tb=10.0, verified=True)
+        _insert_segment(conn, opened_at="2026-08-01T00:00:00+00:00")
+        _open_period(conn, start="2026-08-01T00:00:00+00:00")
+        for i in range(30):
+            d = (datetime(2026, 8, 1) + timedelta(days=i)).strftime("%Y-%m-%d")
+            _insert_day(conn, d, bw=1024*1024*100, coverage=0.95, samples=24)
+        stale_ts = (_clock() - timedelta(days=5)).isoformat()
+        _insert_sample(conn, stale_ts)
+        proj = compute_projection(conn, _clock())
+        assert proj.confidence_state == ConfidenceState.LIMITED
+        assert proj.staleness_fact is not None
+        conn.close()
+
+    def test_limited_degraded_identity(self, tmp_path):
+        conn = init_store(tmp_path / "db")
+        _insert_baseline(conn, tbw_tb=10.0, verified=True)
+        _insert_segment(conn, identity_key=None, degraded=True)
+        _open_period(conn)
+        for i in range(30):
+            d = (datetime(2026, 9, 1) + timedelta(days=i)).strftime("%Y-%m-%d")
+            _insert_day(conn, d, bw=1024*1024*100, coverage=0.95, samples=24)
+        _insert_sample(conn, "2026-09-30T10:00:00+00:00")
+        proj = compute_projection(conn, _clock())
+        assert proj.confidence_state == ConfidenceState.LIMITED
+        assert proj.degraded_identity_fact is not None
+        conn.close()
+
+    def test_unsupported_zero_rate(self, tmp_path):
+        conn = init_store(tmp_path / "db")
+        _insert_baseline(conn, tbw_tb=10.0, verified=True)
+        _insert_segment(conn)
+        _open_period(conn)
+        for i in range(30):
+            d = (datetime(2026, 9, 1) + timedelta(days=i)).strftime("%Y-%m-%d")
+            _insert_day(conn, d, bw=0)
+        _insert_sample(conn, "2026-09-30T10:00:00+00:00")
+        proj = compute_projection(conn, _clock())
+        assert proj.confidence_state == ConfidenceState.UNSUPPORTED
+        assert proj.zero_rate_fact is not None
+        conn.close()
+
+    def test_headline_present_when_projection_exists(self, tmp_path):
+        conn = init_store(tmp_path / "db")
+        _setup_full_store(conn, baseline_kw=dict(tbw_tb=10.0, verified=True))
+        proj = compute_projection(conn, _clock())
+        assert proj.headline_remaining_seconds is not None
+        assert proj.headline_remaining_seconds > 0
+        conn.close()
+
+    def test_headline_absent_when_unavailable(self, tmp_path):
+        conn = init_store(tmp_path / "db")
+        _insert_segment(conn)
+        _open_period(conn)
+        proj = compute_projection(conn, _clock())
+        assert proj.headline_remaining_seconds is None
+        conn.close()
+
+    def test_headline_absent_when_zero_rate(self, tmp_path):
+        conn = init_store(tmp_path / "db")
+        _insert_baseline(conn, tbw_tb=1.0, verified=True)
+        _insert_segment(conn)
+        _open_period(conn)
+        for i in range(20):
+            d = (datetime(2026, 9, 10) + timedelta(days=i)).strftime("%Y-%m-%d")
+            _insert_day(conn, d, bw=0)
+        proj = compute_projection(conn, _clock())
+        assert proj.headline_remaining_seconds is None
+        conn.close()
+
+    def test_facts_always_list(self, tmp_path):
+        conn = init_store(tmp_path / "db")
+        _insert_segment(conn)
+        _open_period(conn)
+        proj = compute_projection(conn, _clock())
+        assert isinstance(proj.contributing_facts, list)
+        conn.close()
+
+    def test_facts_never_empty_for_unavailable(self, tmp_path):
+        conn = init_store(tmp_path / "db")
+        _insert_segment(conn)
+        _open_period(conn)
+        proj = compute_projection(conn, _clock())
+        assert len(proj.contributing_facts) > 0
+        conn.close()
+
+    def test_confidence_never_percentage(self, tmp_path):
+        conn = init_store(tmp_path / "db")
+        _setup_full_store(conn, baseline_kw=dict(tbw_tb=10.0, verified=True))
+        proj = compute_projection(conn, _clock())
+        assert proj.confidence_state in (
+            ConfidenceState.UNSUPPORTED, ConfidenceState.LIMITED, ConfidenceState.SUPPORTED)
+        for f in proj.contributing_facts:
+            if re.match(r"^\\d+%$", f.strip()):
+                pytest.fail("Bare percentage in facts: %r" % f)
+        conn.close()
+
+    def test_status_renders_same_state_as_projection(self, tmp_path):
+        db = tmp_path / "observations.db"
+        conn = init_store(db)
+        _setup_full_store(conn, baseline_kw=dict(tbw_tb=10.0, verified=True))
+        conn.close()
+        now = _clock()
+        with patch("fenris.status.query_service_state", return_value={
+            "boot_enabled": True, "timer_active": True,
+            "last_collect_ok": True, "last_collect_age_s": 60,
+            "last_collect_reason": None,
+        }):
+            status = get_status(store_path=db, clock_now=now,
+                                query_services=True, query_journal=False)
+        assert "Supported" in status or "supported" in status.lower()
+        assert "remaining" in status.lower()
+
+
+# ===================================================================
+# CI-2: TUI/CLI parity
+# ===================================================================
+
+
+class TestCI2Parity:
+    """Verify TUI and CLI share the same constants, formatting, and wording."""
+
+    def test_freshness_constants_shared(self):
+        from fenris import tui as tui_mod
+        from fenris import status as status_mod
+        assert tui_mod.FRESH_THRESHOLD_S == status_mod.FRESH_THRESHOLD_S
+        assert tui_mod.STALENESS_THRESHOLD_S == status_mod.STALENESS_THRESHOLD_S
+
+    def test_grade_freshness_shared(self):
+        from fenris.tui import grade_freshness as tui_gf
+        from fenris.status import grade_freshness as status_gf
+        assert tui_gf is status_gf
+
+    def test_disclosures_shared(self):
+        from fenris.projection import DISCLOSURES as proj_disc
+        from fenris.status import format_disclosures
+        output = format_disclosures()
+        for d in proj_disc:
+            assert d in output
+
+    def test_status_four_facts_match_tui_strip(self, tmp_path):
+        db = tmp_path / "observations.db"
+        conn = init_store(db)
+        _insert_segment(conn)
+        _open_period(conn)
+        for i in range(20):
+            d = (datetime(2026, 9, 10) + timedelta(days=i)).strftime("%Y-%m-%d")
+            _insert_day(conn, d, bw=1024*1024*100)
+        _insert_sample(conn, "2026-09-30T10:00:00+00:00")
+        conn.close()
+        now = _clock()
+        with patch("fenris.status.query_service_state", return_value={
+            "boot_enabled": True, "timer_active": True,
+            "last_collect_ok": True, "last_collect_age_s": 120,
+            "last_collect_reason": None,
+        }):
+            status = get_status(store_path=db, clock_now=now,
+                                query_services=True, query_journal=False)
+        assert "boot:" in status
+        assert "timer:" in status
+        assert "last collect:" in status
+        assert "freshness:" in status
+
+    def test_dashboard_clarity_parity_strings_have_one_status_source(self):
+        """DC-2/DC-3 wording originates in status and the TUI imports it."""
+        status_src = (FENRIS_PKG / "status.py").read_text()
+        tui_src = (FENRIS_PKG / "tui.py").read_text()
+        for wording in (
+            "monitoring: active in background · persists across reboots",
+            "monitoring: does not start on next boot",
+            "monitoring: paused — deliberate disable",
+            "paused time is excluded from your usage habit · resume: fenris monitor resume",
+        ):
+            assert status_src.count(wording) == 1
+            assert wording not in tui_src
+
+    @pytest.mark.asyncio
+    @pytest.mark.parametrize(
+        ("state", "service", "expected_lines"),
+        [
+            (
+                "active_enabled",
+                {"boot_enabled": True, "timer_active": True},
+                ["monitoring: active in background · persists across reboots"],
+            ),
+            (
+                "boot_disabled",
+                {"boot_enabled": False, "timer_active": False},
+                ["monitoring: does not start on next boot"],
+            ),
+            (
+                "deliberately_paused",
+                {"boot_enabled": False, "timer_active": False},
+                [
+                    "monitoring: does not start on next boot",
+                    "monitoring: paused — deliberate disable",
+                    "paused time is excluded from your usage habit · resume: fenris monitor resume",
+                ],
+            ),
+        ],
+    )
+    async def test_dashboard_clarity_monitoring_lines_match_both_views(
+        self, tmp_path, state, service, expected_lines
+    ):
+        """CI-2 synthetic-store sweep covers active, disabled, and paused states."""
+        db = tmp_path / (state + ".db")
+        conn = init_store(db)
+        if state == "active_enabled":
+            ensure_period_open(conn, _clock())
+        elif state == "deliberately_paused":
+            conn.execute(
+                "INSERT INTO monitoring_periods (started_at, ended_at, end_cause) "
+                "VALUES (?, ?, ?)",
+                ("2026-09-30T09:00:00+00:00", "2026-09-30T10:00:00+00:00", "user_disabled"),
+            )
+            conn.commit()
+        conn.close()
+        service_state = {
+            **service,
+            "last_collect_ok": None,
+            "last_collect_age_s": None,
+            "last_collect_reason": None,
+        }
+
+        with patch("fenris.status.query_service_state", return_value=service_state), patch(
+            "fenris.tui.query_service_state", return_value=service_state
+        ):
+            status = get_status(
+                store_path=db, clock_now=_clock(), query_services=True, query_journal=False
+            ).lower()
+            app = FenrisTuiApp(store_path=db)
+            async with app.run_test(size=(100, 40)):
+                tui_text = "\n".join(
+                    (
+                        str(app.query_one("#service-strip").render()),
+                        str(app.query_one("#paused-banner").render()),
+                    )
+                ).lower()
+
+        for expected in expected_lines:
+            assert expected in status
+            assert expected in tui_text
+        if state != "deliberately_paused":
+            assert "monitoring: paused — deliberate disable" not in status
+            assert "monitoring: paused — deliberate disable" not in tui_text
+
+    def test_pause_resume_action_names(self):
+        tui_keys = {b.key for b in FenrisTuiApp.BINDINGS}
+        assert "p" in tui_keys
+        assert "r" in tui_keys
+        assert "c" in tui_keys
+        assert "q" in tui_keys
+
+    def test_empty_store_greeting_both_views(self, tmp_path):
+        db = tmp_path / "observations.db"
+        init_store(db)
+        now = _clock()
+        with patch("fenris.status.query_service_state", return_value={
+            "boot_enabled": False, "timer_active": False,
+            "last_collect_ok": None, "last_collect_age_s": None,
+            "last_collect_reason": None,
+        }):
+            status = get_status(store_path=db, clock_now=now,
+                                query_services=True, query_journal=False)
+        assert "no observations yet" in status.lower()
+
+    def test_store_fault_phrase_both_views(self, tmp_path):
+        status_src = (FENRIS_PKG / "status.py").read_text()
+        tui_src = (FENRIS_PKG / "tui.py").read_text()
+        phrase = "observation store unreadable"
+        assert phrase in status_src
+        assert phrase.lower() in tui_src.lower()
+
+    def test_newer_schema_phrase_both_views(self):
+        status_src = (FENRIS_PKG / "status.py").read_text()
+        phrase = "observation store written by a newer Fenris"
+        assert phrase in status_src
+
+    def test_status_never_prompts(self):
+        status_src = (FENRIS_PKG / "status.py").read_text()
+        assert "input(" not in status_src
+
+
+# ===================================================================
+# CI-3: Prohibition set
+# ===================================================================
+
+
+class TestCI3ProhibitionSet:
+    """Structural codebase checks for every prohibition clause."""
+
+    def _read_all_sources(self):
+        files = {}
+        for py in FENRIS_PKG.glob("*.py"):
+            files[py.name] = py.read_text()
+        return files
+
+    def test_single_acquisition_path(self):
+        """Only fenris-collect may interrogate the device. [2.1, 8.7]
+
+        collector.py contains the acquisition functions; collect.py is the
+        fenris-collect entry point that invokes them.  No other module may
+        reference smartctl.
+        """
+        sources = self._read_all_sources()
+        allowed = {"collector.py", "collect.py"}
+        for name, text in sources.items():
+            if name in allowed:
+                continue
+            assert "smartctl" not in text, (
+                "%s must not contain smartctl" % name
+            )
+
+    def test_no_run_surface(self):
+        """No /run/fenris coordination surface. [1.2, 3]"""
+        sources = self._read_all_sources()
+        for name, text in sources.items():
+            assert "/run/fenris" not in text, (
+                "%s references /run/fenris" % name
+            )
+
+    def test_single_config_key(self):
+        """Config holds exactly one key: device. [8.3]"""
+        status_src = (FENRIS_PKG / "status.py").read_text()
+        in_read_config = False
+        config_keys = []
+        for line in status_src.split("\n"):
+            if "def read_config" in line:
+                in_read_config = True
+            elif in_read_config and line.strip().startswith("def "):
+                break
+            elif in_read_config and "key ==" in line:
+                match = re.search(r'key\s*==\s*["\']([^"\']+)["\']', line)
+                if match:
+                    config_keys.append(match.group(1))
+        assert "device" in config_keys
+        assert len(config_keys) == 1, "Found keys: %s" % config_keys
+
+    def test_no_alerting_machinery(self):
+        """No alerting, notification, or escalation. [9.6]"""
+        sources = self._read_all_sources()
+        alert_keywords = ["send_email", "smtp", "webhook", "push_notification"]
+        for name, text in sources.items():
+            for kw in alert_keywords:
+                for line in text.split("\n"):
+                    stripped = line.strip()
+                    if kw in stripped and not stripped.startswith("#"):
+                        pytest.fail(
+                            "%s contains alerting keyword '%s': %s" % (name, kw, stripped)
+                        )
+
+    def test_no_synthetic_baselines(self):
+        """No synthetic or capacity-derived baseline. [6.1]"""
+        proj_src = (FENRIS_PKG / "projection.py").read_text()
+        assert "synthetic" not in proj_src.lower()
+
+    def test_no_stored_projections(self):
+        """Projections never stored; recomputed on read. [3.7, 6.10]"""
+        store_src = (FENRIS_PKG / "store.py").read_text()
+        create_tables = re.findall(r"CREATE TABLE.*?(?=\n\n|$)", store_src, re.DOTALL)
+        table_names = []
+        for ct in create_tables:
+            m = re.search(r"IF NOT EXISTS\s+(\w+)", ct)
+            if m:
+                table_names.append(m.group(1))
+        assert "projection" not in [t.lower() for t in table_names]
+
+    def test_no_partial_newer_schema_interpretation(self):
+        """Readers refuse newer-schema stores. [3.6, 9.5]"""
+        status_src = (FENRIS_PKG / "status.py").read_text()
+        assert "NewerSchema" in status_src
+        assert "upgrade Fenris" in status_src
+
+    def test_polkit_authorizes_one_binary(self):
+        """Polkit authorizes exactly one binary: fenris-monitor. [8.5]"""
+        monitor_src = (FENRIS_PKG / "monitor.py").read_text()
+        assert "fenris-monitor" in monitor_src or "fenris_monitor" in monitor_src
+        collect_src = (FENRIS_PKG / "collect.py").read_text()
+        assert "polkit" not in collect_src.lower()
+
+    def test_no_hour_interpolation(self):
+        """No absent hour is interpolated or fabricated. [5.3]"""
+        proj_src = (FENRIS_PKG / "projection.py").read_text()
+        assert "interpolat" not in proj_src.lower()
+        assert "fabricat" not in proj_src.lower()
+
+    def test_fenris_sh_not_shipped(self):
+        """fenris.sh is not shipped. [8.8]"""
+        repo_root = Path(__file__).parent.parent
+        assert not (repo_root / "fenris.sh").exists()
+
+
+# ===================================================================
+# CI-4: Required wording and six disclosures
+# ===================================================================
+
+
+class TestCI4WordingAndDisclosures:
+    """Verify exact fixed phrases and disclosures in both views."""
+
+    def test_exactly_six_disclosures(self):
+        assert len(DISCLOSURES) == 6
+
+    def test_disclosure_1_endurance_not_failure(self):
+        assert "endurance projection" in DISCLOSURES[0].lower()
+        assert "hardware-failure" in DISCLOSURES[0].lower() or "failure date" in DISCLOSURES[0].lower()
+
+    def test_disclosure_2_vendor_specific(self):
+        assert "vendor-specific" in DISCLOSURES[1]
+        assert "255 is saturated" in DISCLOSURES[1]
+
+    def test_disclosure_3_warranty_not_failure(self):
+        assert "warranty" in DISCLOSURES[2].lower() or "endurance threshold" in DISCLOSURES[2].lower()
+        assert "failure threshold" in DISCLOSURES[2].lower()
+
+    def test_disclosure_4_duw_rounding(self):
+        assert "DUW" in DISCLOSURES[3]
+        assert "upward-rounded" in DISCLOSURES[3]
+        assert "NAND" in DISCLOSURES[3]
+
+    def test_disclosure_5_quality_depends(self):
+        assert "baseline provenance" in DISCLOSURES[4]
+        assert "future workload" in DISCLOSURES[4]
+
+    def test_disclosure_6_gaps_and_disabled(self):
+        assert "Gaps" in DISCLOSURES[5]
+        assert "deliberately disabled" in DISCLOSURES[5]
+
+    def test_disclosures_render_in_status(self):
+        output = format_disclosures()
+        assert output.startswith("Disclosures")
+        for i in range(1, 7):
+            assert "%d." % i in output
+        for d in DISCLOSURES:
+            assert d in output
+
+    def test_disclosures_render_in_tui(self):
+        tui_src = (FENRIS_PKG / "tui.py").read_text()
+        assert "format_disclosures" in tui_src
+
+    def test_zero_rate_phrase(self):
+        phrase = "no finite projection from this history"
+        proj_src = (FENRIS_PKG / "projection.py").read_text()
+        assert phrase in proj_src
+        status_src = (FENRIS_PKG / "status.py").read_text()
+        assert phrase in status_src
+
+    def test_unavailable_no_baseline_phrase(self):
+        phrase = "no applicable endurance baseline"
+        proj_src = (FENRIS_PKG / "projection.py").read_text()
+        assert phrase in proj_src
+
+    def test_store_fault_phrase(self):
+        phrase = "observation store unreadable"
+        status_src = (FENRIS_PKG / "status.py").read_text()
+        assert phrase in status_src
+        tui_src = (FENRIS_PKG / "tui.py").read_text()
+        assert phrase.lower() in tui_src.lower()
+
+    def test_newer_schema_phrase(self):
+        phrase = "observation store written by a newer Fenris"
+        status_src = (FENRIS_PKG / "status.py").read_text()
+        assert phrase in status_src
+
+    def test_no_observations_phrase(self):
+        phrase = "no observations yet"
+        status_src = (FENRIS_PKG / "status.py").read_text()
+        assert phrase in status_src
+        tui_src = (FENRIS_PKG / "tui.py").read_text()
+        assert phrase in tui_src.lower()
+
+    def test_config_error_phrase(self):
+        phrase = "configuration error:"
+        status_src = (FENRIS_PKG / "status.py").read_text()
+        assert phrase in status_src
+
+    def test_degraded_identity_phrase(self):
+        phrase = "controller identity unavailable"
+        proj_src = (FENRIS_PKG / "projection.py").read_text()
+        assert phrase in proj_src
+        phrase2 = "replacement detection relies on write-counter continuity only"
+        assert phrase2 in proj_src
+
+    def test_scenario_range_only_spread(self):
+        proj_src = (FENRIS_PKG / "projection.py").read_text()
+        assert "confidence interval" not in proj_src.lower()
+
+    def test_no_percentage_in_confidence_rendering(self):
+        for name in ["projection.py", "tui.py", "status.py"]:
+            src = (FENRIS_PKG / name).read_text()
+            assert not re.search(r"\\d+%\\s*confidence", src, re.IGNORECASE), (
+                "Found XX%% confidence in %s" % name
+            )
+
+    def test_status_disclosures_accessible(self):
+        db = Path("/tmp/_ci4_test.db")
+        conn = init_store(db)
+        conn.close()
+        now = _clock()
+        with patch("fenris.status.query_service_state", return_value={
+            "boot_enabled": False, "timer_active": False,
+            "last_collect_ok": None, "last_collect_age_s": None,
+            "last_collect_reason": None,
+        }):
+            result = render_status(store_path=db, clock_now=now,
+                                   query_services=True, query_journal=False,
+                                   show_disclosures=True)
+        assert "Disclosures" in result
+        assert "1." in result
+        assert "6." in result
+        db.unlink(missing_ok=True)

tests/test_changelog.py

@@ -0,0 +1,211 @@
+"""Release-note changelog extraction tests (DC-6, DC-7)."""
+import importlib.util
+import json
+import subprocess
+import sys
+from pathlib import Path
+
+import pytest
+
+
+REPO_ROOT = Path(__file__).resolve().parent.parent
+EXTRACTOR_PATH = REPO_ROOT / "scripts" / "extract_changelog.py"
+RELEASE_REQUEST_PATH = REPO_ROOT / "scripts" / "release_request.py"
+CHANGELOG_PATH = REPO_ROOT / "CHANGELOG.md"
+
+
+def _extractor_module():
+    spec = importlib.util.spec_from_file_location("extract_changelog", EXTRACTOR_PATH)
+    assert spec and spec.loader
+    module = importlib.util.module_from_spec(spec)
+    sys.modules[spec.name] = module
+    spec.loader.exec_module(module)
+    return module
+
+
+def test_extracts_the_requested_version_section_verbatim():
+    extractor = _extractor_module()
+    changelog = """# Changelog
+
+## [Unreleased]
+
+## [1.4.0] - 2026-09-10
+
+### Added
+
+- Show a release summary to consumers.
+
+## [1.3.0] - 2026-09-01
+
+### Fixed
+
+- Preserve the observation history during upgrades.
+"""
+    expected = """## [1.4.0] - 2026-09-10
+
+### Added
+
+- Show a release summary to consumers.
+
+"""
+
+    assert extractor.extract_version_section(changelog, "1.4.0") == expected
+
+
+def test_checked_in_changelog_keeps_unreleased_first_and_categories_limited():
+    lines = CHANGELOG_PATH.read_text(encoding="utf-8").splitlines()
+    unreleased = lines.index("## [Unreleased]")
+    version_headings = [
+        index for index, line in enumerate(lines)
+        if line.startswith("## [") and line != "## [Unreleased]"
+    ]
+    first_version = version_headings[0] if version_headings else len(lines)
+    categories = [
+        line.removeprefix("### ")
+        for line in lines[unreleased + 1:first_version]
+        if line.startswith("### ")
+    ]
+
+    assert unreleased < first_version
+    assert set(categories) <= {"Added", "Changed", "Fixed"}
+
+
+def test_release_footer_verifies_the_clearsigned_checksum_asset():
+    footer = (REPO_ROOT / "packaging" / "release-footer.md").read_text(
+        encoding="utf-8"
+    )
+
+    assert "gpg --output SHA256SUMS --decrypt SHA256SUMS.asc" in footer
+    assert "sha256sum -c SHA256SUMS" in footer
+
+
+@pytest.mark.parametrize(
+    ("changelog", "expected_error"),
+    [
+        ("# Changelog\n\n## [Unreleased]\n", "missing"),
+        (
+            "# Changelog\n\n## [Unreleased]\n\n## [1.4.0] - 2026-09-10\n",
+            "empty",
+        ),
+        (
+            "# Changelog\n\n## [Unreleased]\n\n## [1.4.0] - 2026-02-30\n\n- Add a note.\n",
+            "malformed release date",
+        ),
+    ],
+)
+def test_fails_closed_for_missing_empty_or_malformed_sections(
+    changelog, expected_error
+):
+    extractor = _extractor_module()
+
+    with pytest.raises(extractor.ChangelogError, match=expected_error):
+        extractor.extract_version_section(changelog, "1.4.0")
+
+
+def test_command_emits_a_workflow_error_and_nonzero_status(tmp_path):
+    changelog = tmp_path / "CHANGELOG.md"
+    changelog.write_text("# Changelog\n\n## [Unreleased]\n", encoding="utf-8")
+
+    result = subprocess.run(
+        [sys.executable, str(EXTRACTOR_PATH), str(changelog), "1.4.0"],
+        capture_output=True,
+        text=True,
+        check=False,
+    )
+
+    assert result.returncode != 0
+    assert result.stderr.startswith("::error::")
+    assert "missing" in result.stderr
+
+
+def test_assembles_a_release_body_without_changing_the_section():
+    extractor = _extractor_module()
+    section = "## [1.4.0] - 2026-09-10\n\n### Added\n\n- Show a release summary.\n"
+    footer = "## Install\n\nUse the package channel.\n"
+
+    assert extractor.assemble_release_body(section, footer) == (
+        section + "\n" + footer
+    )
+
+
+def test_command_can_write_the_complete_release_body(tmp_path):
+    changelog = tmp_path / "CHANGELOG.md"
+    changelog.write_text(
+        "# Changelog\n\n## [Unreleased]\n\n## [1.4.0] - 2026-09-10\n\n"
+        "### Added\n\n- Show a release summary.\n",
+        encoding="utf-8",
+    )
+    footer = tmp_path / "footer.md"
+    footer.write_text("## Install\n\nUse the package channel.\n", encoding="utf-8")
+
+    result = subprocess.run(
+        [
+            sys.executable,
+            str(EXTRACTOR_PATH),
+            str(changelog),
+            "1.4.0",
+            "--footer",
+            str(footer),
+        ],
+        capture_output=True,
+        text=True,
+        check=False,
+    )
+
+    assert result.returncode == 0
+    assert result.stdout == (
+        "## [1.4.0] - 2026-09-10\n\n### Added\n\n- Show a release summary.\n\n"
+        "## Install\n\nUse the package channel.\n"
+    )
+
+
+def test_release_request_command_reports_create_or_patch_decisions(tmp_path):
+    body = tmp_path / "release-body.md"
+    body.write_text("## [1.4.0] - 2026-09-10\n", encoding="utf-8")
+
+    create = subprocess.run(
+        [
+            sys.executable,
+            str(RELEASE_REQUEST_PATH),
+            "--version",
+            "1.4.0",
+            "--body-file",
+            str(body),
+        ],
+        capture_output=True,
+        text=True,
+        check=False,
+    )
+    existing = tmp_path / "existing-release.json"
+    existing.write_text('{"id": 17, "assets": []}', encoding="utf-8")
+    patch = subprocess.run(
+        [
+            sys.executable,
+            str(RELEASE_REQUEST_PATH),
+            "--version",
+            "1.4.0",
+            "--body-file",
+            str(body),
+            "--existing-release",
+            str(existing),
+        ],
+        capture_output=True,
+        text=True,
+        check=False,
+    )
+
+    assert create.returncode == patch.returncode == 0
+    assert json.loads(create.stdout) == {
+        "method": "POST",
+        "path": "/releases",
+        "payload": {
+            "tag_name": "v1.4.0",
+            "name": "v1.4.0",
+            "body": "## [1.4.0] - 2026-09-10\n",
+        },
+    }
+    assert json.loads(patch.stdout) == {
+        "method": "PATCH",
+        "path": "/releases/17",
+        "payload": {"body": "## [1.4.0] - 2026-09-10\n"},
+    }

tests/test_collector_history_tracer.py

@@ -0,0 +1,712 @@
+"""Collector history tracer tests (issue #73).
+
+Tests the end-to-end history pipeline: sample acquisition → interval
+derivation → hour observation → day aggregate, with concurrent-read
+safety, cross-hour handling, and display states.
+
+Seams:
+- write side: run_collection() → observation store
+- read side: get_status(), compute_projection() → observation store
+"""
+import os
+import sqlite3
+from datetime import datetime, timedelta, timezone
+from pathlib import Path
+from typing import Any, Dict
+
+import pytest
+import sys
+
+sys.path.insert(0, str(Path(__file__).parent.parent / "src"))
+
+from fenris.collector import run_collection, normalize_identity
+from fenris.store import init_store, get_store_path, SCHEMA_VERSION
+from fenris.monitoring_periods import ensure_period_open, close_period, get_open_period
+from fenris.day_aggregate import derive_day, derive_all_days
+
+
+# ---------------------------------------------------------------------------
+# Fixtures
+# ---------------------------------------------------------------------------
+
+@pytest.fixture
+def smartctl_fixture() -> Dict[str, Any]:
+    """Minimal smartctl -a -j output with required fields."""
+    return {
+        "json_format_version": [1, 0],
+        "smartctl": {"version": [7, 3], "svn_revision": "5155", "build_info": "(local build)"},
+        "nvme_smart_health_information_log": {
+            "critical_warning": 0,
+            "temperature": 35,
+            "available_spare": 100,
+            "available_spare_threshold": 10,
+            "percentage_used": 5,
+            "data_units_written": 12345678,
+            "data_units_read": 9876543,
+            "power_on_hours": 8765,
+            "power_cycles": 1234,
+            "unsafe_shutdowns": 5,
+            "media_errors": 0,
+            "num_err_log_entries": 0,
+        },
+        "user_capacity": {"bytes": 1024000000000, "units": "bytes"},
+        "model_name": "Samsung SSD 970 EVO Plus 1TB",
+        "serial_number": "S4EWNX0N123456",
+        "firmware_version": "2B2QEXM7",
+    }
+
+
+@pytest.fixture
+def sysfs_fixture_tree(tmp_path: Path) -> Path:
+    """Create a minimal sysfs fixture tree with controller identity."""
+    ctrl_dir = tmp_path / "sys" / "class" / "nvme" / "nvme0"
+    ctrl_dir.mkdir(parents=True)
+    (ctrl_dir / "subsysnqn").write_text("nqn.2014-08.org.nvmexpress:uuid:12345678-1234-1234-1234-123456789abc\n")
+    (ctrl_dir / "model").write_text("Samsung SSD 970 EVO Plus 1TB\n")
+    (ctrl_dir / "serial").write_text("S4EWNX0N123456\n")
+    (ctrl_dir / "firmware_rev").write_text("2B2QEXM7\n")
+    transport_dir = ctrl_dir / "transport"
+    transport_dir.mkdir()
+    (transport_dir / "address").write_text("0000:03:00.0")
+    (transport_dir / "trstring").write_text("pcie")
+    return tmp_path
+
+
+@pytest.fixture
+def config_fixture(tmp_path: Path) -> Dict[str, Any]:
+    """Configuration fixture naming the device."""
+    return {
+        "device": "/dev/nvme0",
+        "store_path": str(tmp_path / "observations.db"),
+    }
+
+
+class FakeClock:
+    """Injected clock returning controlled time."""
+    def __init__(self, initial: datetime):
+        self.now = initial
+    def utcnow(self):
+        return self.now
+    def advance(self, **kwargs):
+        self.now = self.now + timedelta(**kwargs)
+
+
+# ---------------------------------------------------------------------------
+# Schema migration: existing data readable at real precision
+# ---------------------------------------------------------------------------
+
+class TestSchemaMigration:
+    """Schema migration 1→2 preserves existing data (issue #73 AC1)."""
+
+    def test_migration_bumps_version(self, tmp_path):
+        """Migration from v1 to v2 succeeds."""
+        from fenris.store import migrate_to_latest, SCHEMA_VERSION
+
+        # Create a v1 store directly (simulating pre-migration state)
+        db = tmp_path / "test.db"
+        conn = sqlite3.connect(str(db))
+        conn.execute("PRAGMA journal_mode=WAL")
+        # Create v1 schema manually
+        conn.execute("""
+            CREATE TABLE samples (
+                id INTEGER PRIMARY KEY AUTOINCREMENT,
+                ts TEXT NOT NULL,
+                device TEXT NOT NULL,
+                subnqn TEXT, sn TEXT, mn TEXT, fr TEXT,
+                capacity_bytes INTEGER, percentage_used INTEGER,
+                available_spare INTEGER, media_errors INTEGER,
+                power_on_hours INTEGER, power_cycles INTEGER,
+                unsafe_shutdowns INTEGER, temperature_c INTEGER,
+                data_units_written INTEGER, data_units_read INTEGER,
+                bytes_written INTEGER, bytes_read INTEGER,
+                critical_warning INTEGER
+            )
+        """)
+        conn.execute("""
+            CREATE TABLE hour_observations (
+                id INTEGER PRIMARY KEY AUTOINCREMENT,
+                hour TEXT NOT NULL UNIQUE,
+                active_seconds INTEGER DEFAULT 0, idle_seconds INTEGER DEFAULT 0,
+                powered_off_seconds INTEGER DEFAULT 0, unknown_seconds INTEGER DEFAULT 0,
+                bytes_written_delta INTEGER DEFAULT 0, bytes_read_delta INTEGER DEFAULT 0,
+                temperature_min INTEGER, temperature_avg REAL, temperature_max INTEGER,
+                sample_count INTEGER DEFAULT 0, coverage REAL DEFAULT 0.0
+            )
+        """)
+        conn.execute("""
+            CREATE TABLE day_aggregates (
+                id INTEGER PRIMARY KEY AUTOINCREMENT,
+                day TEXT NOT NULL UNIQUE,
+                active_seconds INTEGER DEFAULT 0, idle_seconds INTEGER DEFAULT 0,
+                powered_off_seconds INTEGER DEFAULT 0, unknown_seconds INTEGER DEFAULT 0,
+                bytes_written_delta INTEGER DEFAULT 0, bytes_read_delta INTEGER DEFAULT 0,
+                sample_count INTEGER DEFAULT 0, coverage REAL DEFAULT 0.0
+            )
+        """)
+        conn.execute("CREATE TABLE monitoring_periods (id INTEGER PRIMARY KEY AUTOINCREMENT, started_at TEXT NOT NULL, ended_at TEXT, end_cause TEXT)")
+        conn.execute("CREATE TABLE controller_segments (id INTEGER PRIMARY KEY AUTOINCREMENT, opened_at TEXT NOT NULL, identity_key TEXT, identity_degraded BOOLEAN DEFAULT 0, subnqn TEXT, sn TEXT, mn TEXT, fr TEXT, vid TEXT, ssvid TEXT, transport TEXT)")
+        conn.execute("CREATE TABLE endurance_baseline (id INTEGER PRIMARY KEY AUTOINCREMENT, tbw_terabytes REAL NOT NULL, source_url TEXT, document_revision TEXT, entry_date TEXT, model_string TEXT, nominal_capacity_bytes INTEGER, validated_by TEXT, verified BOOLEAN DEFAULT 0, created_at TEXT NOT NULL, updated_at TEXT NOT NULL)")
+        conn.execute("CREATE TABLE store_metadata (key TEXT PRIMARY KEY, value TEXT NOT NULL)")
+        conn.execute("PRAGMA user_version=1")
+        conn.execute("INSERT INTO samples (ts, device, mn, sn, fr, capacity_bytes, percentage_used, available_spare, media_errors, power_on_hours, power_cycles, unsafe_shutdowns, temperature_c, data_units_written, data_units_read, bytes_written, bytes_read, critical_warning) VALUES ('2026-09-01T12:00:00+00:00', '/dev/nvme0', 'Test', 'SN', 'FR', 1000000000000, 5, 100, 0, 1000, 100, 0, 35, 1000000, 500000, 512000000000, 256000000000, 0)")
+        conn.commit()
+        conn.close()
+
+        # Migrate
+        steps = migrate_to_latest(db)
+        assert steps == 1
+
+        # Verify data preserved
+        conn = sqlite3.connect(str(db))
+        row = conn.execute("SELECT ts, mn FROM samples").fetchone()
+        version = conn.execute("PRAGMA user_version").fetchone()[0]
+        conn.close()
+        assert row[0] == "2026-09-01T12:00:00+00:00"
+        assert row[1] == "Test"
+        assert version == SCHEMA_VERSION
+
+    def test_newer_schema_refused(self, tmp_path):
+        """Store with user_version > SCHEMA_VERSION is refused."""
+        db = tmp_path / "test.db"
+        conn = sqlite3.connect(str(db))
+        conn.execute("PRAGMA user_version=%d" % (SCHEMA_VERSION + 1))
+        conn.commit()
+        conn.close()
+
+        with pytest.raises(ValueError, match="newer Fenris"):
+            init_store(db)
+
+    def test_existing_data_preserved_after_migration(self, config_fixture,
+                                                      smartctl_fixture,
+                                                      sysfs_fixture_tree):
+        """Existing sample data is not lost or modified by migration."""
+        clock = FakeClock(datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc))
+
+        # Write first sample
+        run_collection(smartctl_fixture, sysfs_fixture_tree / "sys" / "class" / "nvme" / "nvme0",
+                       config_fixture, clock)
+
+        conn = sqlite3.connect(config_fixture["store_path"])
+        row = conn.execute("SELECT ts, device, bytes_written FROM samples").fetchone()
+        conn.close()
+
+        assert row[0] == "2026-09-01T12:00:00+00:00"
+        assert row[1] == "/dev/nvme0"
+        assert row[2] == 12345678 * 512000
+
+
+# ---------------------------------------------------------------------------
+# Collector publishes samples, intervals, hour observations, day aggregates
+# ---------------------------------------------------------------------------
+
+class TestCollectorDerivation:
+    """Collector derives hour observations and day aggregates (issue #73 AC2)."""
+
+    def _make_sample(self, duw_units: int, ts: str) -> Dict[str, Any]:
+        """Build a smartctl fixture with specific DUW."""
+        return {
+            "json_format_version": [1, 0],
+            "smartctl": {"version": [7, 3], "svn_revision": "5155", "build_info": "(local build)"},
+            "nvme_smart_health_information_log": {
+                "critical_warning": 0,
+                "temperature": 35,
+                "available_spare": 100,
+                "available_spare_threshold": 10,
+                "percentage_used": 5,
+                "data_units_written": duw_units,
+                "data_units_read": 9876543,
+                "power_on_hours": 8765,
+                "power_cycles": 1234,
+                "unsafe_shutdowns": 5,
+                "media_errors": 0,
+                "num_err_log_entries": 0,
+            },
+            "user_capacity": {"bytes": 1024000000000, "units": "bytes"},
+            "model_name": "Samsung SSD 970 EVO Plus 1TB",
+            "serial_number": "S4EWNX0N123456",
+            "firmware_version": "2B2QEXM7",
+        }
+
+    def test_same_hour_20mb_derives_hour_obs(self, config_fixture, sysfs_fixture_tree):
+        """Two samples in same hour with 20 MB delta → hour_obs gets 20 MB."""
+        t1 = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        t2 = datetime(2026, 9, 1, 12, 5, 0, tzinfo=timezone.utc)
+
+        # DUW units: 12345678 * 512000 = ~6.3 TB; 20 MB = 20*1024*1024 / 512000 ≈ 40 units
+        duw1 = 12345678
+        duw2 = duw1 + 40  # ~20 MB more
+
+        clock1 = FakeClock(t1)
+        s1 = self._make_sample(duw1, t1.isoformat())
+        r1 = run_collection(s1, sysfs_fixture_tree / "sys" / "class" / "nvme" / "nvme0",
+                            config_fixture, clock1)
+        assert r1["ok"]
+
+        clock2 = FakeClock(t2)
+        s2 = self._make_sample(duw2, t2.isoformat())
+        r2 = run_collection(s2, sysfs_fixture_tree / "sys" / "class" / "nvme" / "nvme0",
+                            config_fixture, clock2)
+        assert r2["ok"]
+
+        # Check hour_observation was derived
+        conn = sqlite3.connect(config_fixture["store_path"])
+        hour = conn.execute(
+            "SELECT bytes_written_delta, sample_count FROM hour_observations WHERE hour LIKE '2026-09-01T12%'"
+        ).fetchone()
+        conn.close()
+
+        assert hour is not None, "Hour observation should exist for 12:00"
+        assert hour[1] >= 2  # at least 2 samples contributed
+        # bytes_written_delta should be the 20 MB delta (40 * 512000 = 20480000)
+        assert hour[0] == 40 * 512000
+
+    def test_zero_delta_derives_hour_obs(self, config_fixture, sysfs_fixture_tree):
+        """Two samples in same hour with no DUW change → 0 B written."""
+        t1 = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        t2 = datetime(2026, 9, 1, 12, 5, 0, tzinfo=timezone.utc)
+
+        duw = 12345678  # same for both
+
+        clock1 = FakeClock(t1)
+        s1 = self._make_sample(duw, t1.isoformat())
+        run_collection(s1, sysfs_fixture_tree / "sys" / "class" / "nvme" / "nvme0",
+                       config_fixture, clock1)
+
+        clock2 = FakeClock(t2)
+        s2 = self._make_sample(duw, t2.isoformat())
+        run_collection(s2, sysfs_fixture_tree / "sys" / "class" / "nvme" / "nvme0",
+                       config_fixture, clock2)
+
+        conn = sqlite3.connect(config_fixture["store_path"])
+        hour = conn.execute(
+            "SELECT bytes_written_delta FROM hour_observations WHERE hour LIKE '2026-09-01T12%'"
+        ).fetchone()
+        conn.close()
+
+        assert hour is not None
+        assert hour[0] == 0
+
+    def test_cross_hour_100mb_unattributed(self, config_fixture, sysfs_fixture_tree):
+        """Samples in different hours → delta is unattributed to any hour."""
+        t1 = datetime(2026, 9, 1, 11, 55, 0, tzinfo=timezone.utc)
+        t2 = datetime(2026, 9, 1, 12, 5, 0, tzinfo=timezone.utc)
+
+        duw1 = 12345678
+        duw2 = duw1 + 200  # ~100 MB
+
+        clock1 = FakeClock(t1)
+        s1 = self._make_sample(duw1, t1.isoformat())
+        run_collection(s1, sysfs_fixture_tree / "sys" / "class" / "nvme" / "nvme0",
+                       config_fixture, clock1)
+
+        clock2 = FakeClock(t2)
+        s2 = self._make_sample(duw2, t2.isoformat())
+        run_collection(s2, sysfs_fixture_tree / "sys" / "class" / "nvme" / "nvme0",
+                       config_fixture, clock2)
+
+        conn = sqlite3.connect(config_fixture["store_path"])
+
+        # Hour observations should NOT contain the cross-hour delta
+        hour11 = conn.execute(
+            "SELECT bytes_written_delta FROM hour_observations WHERE hour LIKE '2026-09-01T11%'"
+        ).fetchone()
+        hour12 = conn.execute(
+            "SELECT bytes_written_delta FROM hour_observations WHERE hour LIKE '2026-09-01T12%'"
+        ).fetchone()
+        conn.close()
+
+        # Neither hour should have the full 100 MB delta attributed
+        # (they may have 0 or partial, but not 200*512000)
+        full_delta = 200 * 512000
+        if hour11 is not None:
+            assert hour11[0] != full_delta, "Hour 11 should not have full cross-hour delta"
+        if hour12 is not None:
+            assert hour12[0] != full_delta, "Hour 12 should not have full cross-hour delta"
+
+    def test_readonly_sees_consistent_snapshot(self, config_fixture, sysfs_fixture_tree):
+        """A read-only reader sees valid pre- or post-publication snapshot."""
+        t1 = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        t2 = datetime(2026, 9, 1, 12, 5, 0, tzinfo=timezone.utc)
+
+        clock1 = FakeClock(t1)
+        run_collection(self._make_sample(12345678, t1.isoformat()),
+                       sysfs_fixture_tree / "sys" / "class" / "nvme" / "nvme0",
+                       config_fixture, clock1)
+
+        # Open read-only
+        ro_conn = sqlite3.connect(
+            "file:%s?mode=ro" % config_fixture["store_path"], uri=True
+        )
+        count_before = ro_conn.execute("SELECT COUNT(*) FROM samples").fetchone()[0]
+        ro_conn.close()
+        assert count_before == 1
+
+        # Write second sample
+        clock2 = FakeClock(t2)
+        run_collection(self._make_sample(12345718, t2.isoformat()),
+                       sysfs_fixture_tree / "sys" / "class" / "nvme" / "nvme0",
+                       config_fixture, clock2)
+
+        # Read-only reader sees 2 samples now
+        ro_conn2 = sqlite3.connect(
+            "file:%s?mode=ro" % config_fixture["store_path"], uri=True
+        )
+        count_after = ro_conn2.execute("SELECT COUNT(*) FROM samples").fetchone()[0]
+        ro_conn2.close()
+        assert count_after == 2
+
+
+# ---------------------------------------------------------------------------
+# Display states: awaiting first sample, awaiting another sample
+# ---------------------------------------------------------------------------
+
+class TestDisplayStates:
+    """Display states for zero/one/two+ samples (issue #73 AC3)."""
+
+    def test_zero_samples_awaiting_first(self, tmp_path):
+        """Zero samples → 'awaiting first sample' state."""
+        from fenris.status import get_status
+        db = tmp_path / "test.db"
+        init_store(db)
+        now = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        from unittest.mock import patch
+        with patch("fenris.status.query_service_state", return_value={
+            "boot_enabled": False, "timer_active": False,
+            "last_collect_ok": None, "last_collect_age_s": None,
+            "last_collect_reason": None,
+        }):
+            result = get_status(store_path=db, clock_now=now,
+                                query_services=False, query_journal=False)
+        assert "no observations yet" in result.lower() or "awaiting" in result.lower()
+
+    def test_one_sample_awaiting_another(self, tmp_path):
+        """One sample → 'awaiting another sample' state."""
+        from fenris.status import get_status
+        db = tmp_path / "test.db"
+        conn = init_store(db)
+        conn.execute(
+            "INSERT INTO samples (ts, device, mn, sn, fr, capacity_bytes, "
+            "percentage_used, available_spare, media_errors, power_on_hours, "
+            "power_cycles, unsafe_shutdowns, temperature_c, "
+            "data_units_written, data_units_read, bytes_written, bytes_read, "
+            "critical_warning) "
+            "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)",
+            ("2026-09-01T12:00:00+00:00", "/dev/nvme0", "Test", "SN", "FR",
+             1000000000000, 5, 100, 0, 1000, 100, 0, 35,
+             1000000, 500000, 512000000000, 256000000000, 0),
+        )
+        conn.commit()
+        conn.close()
+        now = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        from unittest.mock import patch
+        with patch("fenris.status.query_service_state", return_value={
+            "boot_enabled": False, "timer_active": False,
+            "last_collect_ok": None, "last_collect_age_s": None,
+            "last_collect_reason": None,
+        }):
+            result = get_status(store_path=db, clock_now=now,
+                                query_services=False, query_journal=False)
+        # Should mention awaiting or insufficient data
+        lower = result.lower()
+        assert "awaiting" in lower or "another sample" in lower or "no projection" in lower
+
+    def test_one_sample_awaiting_another_in_tui(self, tmp_path):
+        """One sample → TUI shows awaiting state."""
+        from fenris.tui import FenrisTuiApp, _query_service_facts
+        db = tmp_path / "test.db"
+        conn = init_store(db)
+        conn.execute(
+            "INSERT INTO samples (ts, device, mn, sn, fr, capacity_bytes, "
+            "percentage_used, available_spare, media_errors, power_on_hours, "
+            "power_cycles, unsafe_shutdowns, temperature_c, "
+            "data_units_written, data_units_read, bytes_written, bytes_read, "
+            "critical_warning) "
+            "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)",
+            ("2026-09-01T12:00:00+00:00", "/dev/nvme0", "Test", "SN", "FR",
+             1000000000000, 5, 100, 0, 1000, 100, 0, 35,
+             1000000, 500000, 512000000000, 256000000000, 0),
+        )
+        conn.commit()
+        conn.close()
+        now = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        # Test the projection handles single sample
+        from fenris.projection import compute_projection, ConfidenceState
+        conn = sqlite3.connect(db)
+        proj = compute_projection(conn, now)
+        conn.close()
+        # With only one sample, projection should be unavailable
+        assert proj.confidence_state == ConfidenceState.UNSUPPORTED
+
+    def test_two_same_hour_samples_show_measured_usage(self, config_fixture, sysfs_fixture_tree):
+        """Two compatible same-hour samples show measured usage."""
+        t1 = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        t2 = datetime(2026, 9, 1, 12, 5, 0, tzinfo=timezone.utc)
+
+        clock1 = FakeClock(t1)
+        run_collection(self._make_sample_helper(12345678), sysfs_fixture_tree / "sys" / "class" / "nvme" / "nvme0",
+                       config_fixture, clock1)
+
+        clock2 = FakeClock(t2)
+        run_collection(self._make_sample_helper(12345718), sysfs_fixture_tree / "sys" / "class" / "nvme" / "nvme0",
+                       config_fixture, clock2)
+
+        from fenris.status import get_status
+        from unittest.mock import patch
+        now = datetime(2026, 9, 1, 12, 10, 0, tzinfo=timezone.utc)
+        with patch("fenris.status.query_service_state", return_value={
+            "boot_enabled": False, "timer_active": False,
+            "last_collect_ok": None, "last_collect_age_s": None,
+            "last_collect_reason": None,
+        }):
+            result = get_status(store_path=Path(config_fixture["store_path"]),
+                                clock_now=now, query_services=False, query_journal=False)
+        # Should not say "no observations" or "awaiting"
+        lower = result.lower()
+        assert "no observations yet" not in lower
+
+    def _make_sample_helper(self, duw_units: int) -> Dict[str, Any]:
+        return {
+            "json_format_version": [1, 0],
+            "smartctl": {"version": [7, 3], "svn_revision": "5155", "build_info": "(local build)"},
+            "nvme_smart_health_information_log": {
+                "critical_warning": 0, "temperature": 35,
+                "available_spare": 100, "available_spare_threshold": 10,
+                "percentage_used": 5, "data_units_written": duw_units,
+                "data_units_read": 9876543, "power_on_hours": 8765,
+                "power_cycles": 1234, "unsafe_shutdowns": 5,
+                "media_errors": 0, "num_err_log_entries": 0,
+            },
+            "user_capacity": {"bytes": 1024000000000, "units": "bytes"},
+            "model_name": "Samsung SSD 970 EVO Plus 1TB",
+            "serial_number": "S4EWNX0N123456",
+            "firmware_version": "2B2QEXM7",
+        }
+
+
+# ---------------------------------------------------------------------------
+# Pause crossing and counter reset
+# ---------------------------------------------------------------------------
+
+class TestPauseCrossing:
+    """Delta across monitoring period gap (issue #73 AC4)."""
+
+    def test_pause_crossing_preserves_prior_history(self, config_fixture, sysfs_fixture_tree):
+        """Delta across a paused period preserves prior hour observations."""
+        t1 = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        t_pause = datetime(2026, 9, 1, 13, 0, 0, tzinfo=timezone.utc)
+        t_resume = datetime(2026, 9, 1, 14, 0, 0, tzinfo=timezone.utc)
+        t2 = datetime(2026, 9, 1, 14, 5, 0, tzinfo=timezone.utc)
+
+        duw1 = 12345678
+        duw2 = duw1 + 100
+
+        # First sample (opens period)
+        clock1 = FakeClock(t1)
+        run_collection(self._make_sample_for_pause(duw1), sysfs_fixture_tree / "sys" / "class" / "nvme" / "nvme0",
+                       config_fixture, clock1)
+
+        # Pause
+        conn = sqlite3.connect(config_fixture["store_path"])
+        close_period(conn, t_pause, "user_disabled")
+        conn.close()
+
+        # Resume with new sample
+        clock_resume = FakeClock(t_resume)
+        run_collection(self._make_sample_for_pause(duw1), sysfs_fixture_tree / "sys" / "class" / "nvme" / "nvme0",
+                       config_fixture, clock_resume)
+
+        # Second sample after resume
+        clock2 = FakeClock(t2)
+        run_collection(self._make_sample_for_pause(duw2), sysfs_fixture_tree / "sys" / "class" / "nvme" / "nvme0",
+                       config_fixture, clock2)
+
+        # Verify prior hour observations are intact
+        conn = sqlite3.connect(config_fixture["store_path"])
+        hour_12 = conn.execute(
+            "SELECT bytes_written_delta FROM hour_observations WHERE hour LIKE '2026-09-01T12%'"
+        ).fetchone()
+        conn.close()
+
+        # Hour 12 should still have data from the first collection
+        assert hour_12 is not None, "Prior hour observation should be preserved"
+
+    def _make_sample_for_pause(self, duw_units: int) -> Dict[str, Any]:
+        return {
+            "json_format_version": [1, 0],
+            "smartctl": {"version": [7, 3], "svn_revision": "5155", "build_info": "(local build)"},
+            "nvme_smart_health_information_log": {
+                "critical_warning": 0, "temperature": 35,
+                "available_spare": 100, "available_spare_threshold": 10,
+                "percentage_used": 5, "data_units_written": duw_units,
+                "data_units_read": 9876543, "power_on_hours": 8765,
+                "power_cycles": 1234, "unsafe_shutdowns": 5,
+                "media_errors": 0, "num_err_log_entries": 0,
+            },
+            "user_capacity": {"bytes": 1024000000000, "units": "bytes"},
+            "model_name": "Samsung SSD 970 EVO Plus 1TB",
+            "serial_number": "S4EWNX0N123456",
+            "firmware_version": "2B2QEXM7",
+        }
+
+
+class TestCounterReset:
+    """Counter reset / replacement opens new segment (issue #73 AC6)."""
+
+    def test_duw_decrease_opens_new_segment(self, config_fixture, sysfs_fixture_tree):
+        """DUW decrease triggers new segment."""
+        t1 = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        t2 = datetime(2026, 9, 1, 12, 5, 0, tzinfo=timezone.utc)
+
+        duw1 = 12345678
+        duw2 = duw1 - 100  # decrease = reset
+
+        clock1 = FakeClock(t1)
+        run_collection(self._make_sample_for_reset(duw1), sysfs_fixture_tree / "sys" / "class" / "nvme" / "nvme0",
+                       config_fixture, clock1)
+
+        clock2 = FakeClock(t2)
+        run_collection(self._make_sample_for_reset(duw2), sysfs_fixture_tree / "sys" / "class" / "nvme" / "nvme0",
+                       config_fixture, clock2)
+
+        conn = sqlite3.connect(config_fixture["store_path"])
+        segments = conn.execute("SELECT COUNT(*) FROM controller_segments").fetchone()[0]
+        samples = conn.execute("SELECT COUNT(*) FROM samples").fetchone()[0]
+        conn.close()
+
+        # Should have 2 segments (new one opened for DUW decrease)
+        assert segments == 2
+        # Should have 2 samples
+        assert samples == 2
+
+    def _make_sample_for_reset(self, duw_units: int) -> Dict[str, Any]:
+        return {
+            "json_format_version": [1, 0],
+            "smartctl": {"version": [7, 3], "svn_revision": "5155", "build_info": "(local build)"},
+            "nvme_smart_health_information_log": {
+                "critical_warning": 0, "temperature": 35,
+                "available_spare": 100, "available_spare_threshold": 10,
+                "percentage_used": 5, "data_units_written": duw_units,
+                "data_units_read": 9876543, "power_on_hours": 8765,
+                "power_cycles": 1234, "unsafe_shutdowns": 5,
+                "media_errors": 0, "num_err_log_entries": 0,
+            },
+            "user_capacity": {"bytes": 1024000000000, "units": "bytes"},
+            "model_name": "Samsung SSD 970 EVO Plus 1TB",
+            "serial_number": "S4EWNX0N123456",
+            "firmware_version": "2B2QEXM7",
+        }
+
+
+# ---------------------------------------------------------------------------
+# Derivation failure preserves prior history
+# ---------------------------------------------------------------------------
+
+class TestDerivationFailure:
+    """Injected derivation failure preserves prior history (issue #73 AC6)."""
+
+    def test_failed_derivation_preserves_samples(self, config_fixture, sysfs_fixture_tree):
+        """If derivation fails after sample write, prior data is intact."""
+        t1 = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        t2 = datetime(2026, 9, 1, 12, 5, 0, tzinfo=timezone.utc)
+
+        clock1 = FakeClock(t1)
+        run_collection(self._make_sample_for_failure(12345678),
+                       sysfs_fixture_tree / "sys" / "class" / "nvme" / "nvme0",
+                       config_fixture, clock1)
+
+        # Verify first sample exists
+        conn = sqlite3.connect(config_fixture["store_path"])
+        count = conn.execute("SELECT COUNT(*) FROM samples").fetchone()[0]
+        conn.close()
+        assert count == 1
+
+        # Second sample with valid data should succeed
+        clock2 = FakeClock(t2)
+        r2 = run_collection(self._make_sample_for_failure(12345718),
+                            sysfs_fixture_tree / "sys" / "class" / "nvme" / "nvme0",
+                            config_fixture, clock2)
+        assert r2["ok"]
+
+        # Both samples should exist
+        conn = sqlite3.connect(config_fixture["store_path"])
+        count = conn.execute("SELECT COUNT(*) FROM samples").fetchone()[0]
+        conn.close()
+        assert count == 2
+
+    def _make_sample_for_failure(self, duw_units: int) -> Dict[str, Any]:
+        return {
+            "json_format_version": [1, 0],
+            "smartctl": {"version": [7, 3], "svn_revision": "5155", "build_info": "(local build)"},
+            "nvme_smart_health_information_log": {
+                "critical_warning": 0, "temperature": 35,
+                "available_spare": 100, "available_spare_threshold": 10,
+                "percentage_used": 5, "data_units_written": duw_units,
+                "data_units_read": 9876543, "power_on_hours": 8765,
+                "power_cycles": 1234, "unsafe_shutdowns": 5,
+                "media_errors": 0, "num_err_log_entries": 0,
+            },
+            "user_capacity": {"bytes": 1024000000000, "units": "bytes"},
+            "model_name": "Samsung SSD 970 EVO Plus 1TB",
+            "serial_number": "S4EWNX0N123456",
+            "firmware_version": "2B2QEXM7",
+        }
+
+
+# ---------------------------------------------------------------------------
+# Monitoring period is opened by collector
+# ---------------------------------------------------------------------------
+
+class TestMonitoringPeriod:
+    """Collector ensures monitoring period is open (issue #73 AC2)."""
+
+    def test_first_sample_opens_period(self, config_fixture, sysfs_fixture_tree):
+        """First collection run opens a monitoring period."""
+        t1 = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        clock1 = FakeClock(t1)
+        run_collection(self._make_sample_simple(), sysfs_fixture_tree / "sys" / "class" / "nvme" / "nvme0",
+                       config_fixture, clock1)
+
+        conn = sqlite3.connect(config_fixture["store_path"])
+        period = get_open_period(conn)
+        conn.close()
+
+        assert period is not None, "A monitoring period should be open"
+
+    def test_subsequent_sample_keeps_period_open(self, config_fixture, sysfs_fixture_tree):
+        """Subsequent collection runs keep the period open."""
+        t1 = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        t2 = datetime(2026, 9, 1, 12, 5, 0, tzinfo=timezone.utc)
+
+        clock1 = FakeClock(t1)
+        run_collection(self._make_sample_simple(), sysfs_fixture_tree / "sys" / "class" / "nvme" / "nvme0",
+                       config_fixture, clock1)
+
+        clock2 = FakeClock(t2)
+        run_collection(self._make_sample_simple(), sysfs_fixture_tree / "sys" / "class" / "nvme" / "nvme0",
+                       config_fixture, clock2)
+
+        conn = sqlite3.connect(config_fixture["store_path"])
+        period = get_open_period(conn)
+        periods_count = conn.execute("SELECT COUNT(*) FROM monitoring_periods").fetchone()[0]
+        conn.close()
+
+        assert period is not None
+        assert periods_count == 1  # Still only one period
+
+    def _make_sample_simple(self) -> Dict[str, Any]:
+        return {
+            "json_format_version": [1, 0],
+            "smartctl": {"version": [7, 3], "svn_revision": "5155", "build_info": "(local build)"},
+            "nvme_smart_health_information_log": {
+                "critical_warning": 0, "temperature": 35,
+                "available_spare": 100, "available_spare_threshold": 10,
+                "percentage_used": 5, "data_units_written": 12345678,
+                "data_units_read": 9876543, "power_on_hours": 8765,
+                "power_cycles": 1234, "unsafe_shutdowns": 5,
+                "media_errors": 0, "num_err_log_entries": 0,
+            },
+            "user_capacity": {"bytes": 1024000000000, "units": "bytes"},
+            "model_name": "Samsung SSD 970 EVO Plus 1TB",
+            "serial_number": "S4EWNX0N123456",
+            "firmware_version": "2B2QEXM7",
+        }

tests/test_collector_tracer.py

@@ -0,0 +1,359 @@
+"""Collector tracer bullet test.
+
+Tests the thinnest complete write path through the system:
+- Input: smartctl-JSON fixture, sysfs fixture tree, config fixture, injected clock
+- Output: resulting store contents, run outcome
+
+Seam: write side of the observation store database file.
+"""
+import json
+import os
+import sqlite3
+import tempfile
+from datetime import datetime, timezone
+from pathlib import Path
+from typing import Any, Dict, Generator
+
+import pytest
+
+# Add src to path for imports
+import sys
+sys.path.insert(0, str(Path(__file__).parent.parent / "src"))
+
+from fenris.collector import run_collection, AcquisitionError, InvariantViolationError
+from fenris.store import init_store, get_store_path
+
+
+# Fixtures
+
+@pytest.fixture
+def smartctl_fixture() -> Dict[str, Any]:
+    """Minimal smartctl -a -j output with required fields."""
+    return {
+        "json_format_version": [1, 0],
+        "smartctl": {"version": [7, 3], "svn_revision": "5155", "build_info": "(local build)"},
+        "nvme_smart_health_information_log": {
+            "critical_warning": 0,
+            "temperature": 35,
+            "available_spare": 100,
+            "available_spare_threshold": 10,
+            "percentage_used": 5,
+            "data_units_written": 12345678,
+            "data_units_read": 9876543,
+            "power_on_hours": 8765,
+            "power_cycles": 1234,
+            "unsafe_shutdowns": 5,
+            "media_errors": 0,
+            "num_err_log_entries": 0,
+        },
+        "user_capacity": {"bytes": 1024000000000, "units": "bytes"},
+        "model_name": "Samsung SSD 970 EVO Plus 1TB",
+        "serial_number": "S4EWNX0N123456",
+        "firmware_version": "2B2QEXM7",
+    }
+
+
+@pytest.fixture
+def sysfs_fixture_tree(tmp_path: Path) -> Path:
+    """Create a minimal sysfs fixture tree with controller identity."""
+    ctrl_dir = tmp_path / "sys" / "class" / "nvme" / "nvme0"
+    ctrl_dir.mkdir(parents=True)
+    
+    # Controller identity files
+    (ctrl_dir / "subsysnqn").write_text("nqn.2014-08.org.nvmexpress:uuid:12345678-1234-1234-1234-123456789abc\n")
+    (ctrl_dir / "model").write_text("Samsung SSD 970 EVO Plus 1TB\n")
+    (ctrl_dir / "serial").write_text("S4EWNX0N123456\n")
+    (ctrl_dir / "firmware_rev").write_text("2B2QEXM7\n")
+    
+    # Transport info (optional, but we'll include it)
+    transport_dir = ctrl_dir / "transport"
+    transport_dir.mkdir()
+    (transport_dir / "address").write_text("0000:03:00.0")
+    (transport_dir / "trstring").write_text("pcie")
+    
+    return tmp_path
+
+
+@pytest.fixture
+def config_fixture(tmp_path: Path) -> Dict[str, Any]:
+    """Configuration fixture naming the device."""
+    return {
+        "device": "/dev/nvme0",
+        "store_path": str(tmp_path / "observations.db"),
+    }
+
+
+@pytest.fixture
+def clock_fixture():
+    """Injected clock returning fixed time."""
+    class FakeClock:
+        def __init__(self):
+            self.now = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        
+        def utcnow(self):
+            return self.now
+    
+    return FakeClock()
+
+
+# Test: Collector writes one well-formed sample
+
+def test_collector_writes_one_sample(
+    smartctl_fixture: Dict[str, Any],
+    sysfs_fixture_tree: Path,
+    config_fixture: Dict[str, Any],
+    clock_fixture,
+):
+    """Given a smartctl fixture and sysfs fixture tree,
+    when the collector runs,
+    then one well-formed sample is written to the observation store."""
+    result = run_collection(
+        smartctl_data=smartctl_fixture,
+        sysfs_path=sysfs_fixture_tree / "sys" / "class" / "nvme" / "nvme0",
+        config=config_fixture,
+        clock=clock_fixture,
+    )
+    
+    # Verify run succeeded
+    assert result["ok"] is True, f"Collection failed: {result.get('error')}"
+    
+    # Verify store contents
+    conn = sqlite3.connect(config_fixture["store_path"])
+    cursor = conn.execute("SELECT COUNT(*) FROM samples")
+    count = cursor.fetchone()[0]
+    assert count == 1
+    
+    cursor = conn.execute("SELECT * FROM samples")
+    row = cursor.fetchone()
+    assert row is not None
+    
+    # Verify row contents match fixtures
+    # Row structure: id, ts, device, subnqn, sn, mn, fr, capacity_bytes,
+    # percentage_used, available_spare, media_errors, power_on_hours, power_cycles,
+    # unsafe_shutdowns, temperature_c, data_units_written, data_units_read,
+    # bytes_written, bytes_read, critical_warning
+    assert row[2] == "/dev/nvme0"  # device
+    assert row[3] == "nqn.2014-08.org.nvmexpress:uuid:12345678-1234-1234-1234-123456789abc"  # subnqn
+    assert row[4] == "S4EWNX0N123456"  # sn
+    assert row[5] == "Samsung SSD 970 EVO Plus 1TB"  # mn
+    assert row[6] == "2B2QEXM7"  # fr
+    assert row[7] == 1024000000000  # capacity_bytes
+    assert row[8] == 5  # percentage_used
+    assert row[15] == 12345678  # data_units_written
+    assert row[17] == 12345678 * 512000  # bytes_written
+    
+    conn.close()
+
+
+# Test: Identity normalization applied exactly once at write time
+
+def test_identity_normalization(
+    smartctl_fixture: Dict[str, Any],
+    sysfs_fixture_tree: Path,
+    config_fixture: Dict[str, Any],
+    clock_fixture,
+):
+    """Given sysfs identity with trailing spaces/newlines,
+    when the collector writes,
+    then identity is normalized exactly once at write time."""
+    # Create identity with trailing whitespace
+    identity = {
+        "subnqn": "nqn.2014-08.org.nvmexpress:uuid:12345678-1234-1234-1234-123456789abc  \n",
+        "mn": "Samsung SSD 970 EVO Plus 1TB\n",
+        "sn": "S4EWNX0N123456\n",
+        "fr": "2B2QEXM7",
+        "transport": "pcie",
+    }
+    
+    from fenris.collector import normalize_identity
+    
+    # Normalize once
+    key1 = normalize_identity(identity)
+    # Normalize again - should be identical
+    key2 = normalize_identity(identity)
+    
+    assert key1 == key2
+    assert key1 == "nqn.2014-08.org.nvmexpress:uuid:12345678-1234-1234-1234-123456789abc"
+    assert "\n" not in key1
+    assert key1 == key1.rstrip()  # No trailing whitespace
+
+
+# Test: Any acquisition failure fails the whole run
+
+def test_acquisition_failure_fails_run(
+    sysfs_fixture_tree: Path,
+    config_fixture: Dict[str, Any],
+    clock_fixture,
+):
+    """Given a smartctl fixture with missing fields,
+    when the collector runs,
+    then the whole run fails and writes nothing."""
+    # Missing required field
+    bad_smartctl = {
+        "json_format_version": [1, 0],
+        "smartctl": {"version": [7, 3]},
+        # Missing nvme_smart_health_information_log
+    }
+    
+    result = run_collection(
+        smartctl_data=bad_smartctl,
+        sysfs_path=sysfs_fixture_tree / "sys" / "class" / "nvme" / "nvme0",
+        config=config_fixture,
+        clock=clock_fixture,
+    )
+    
+    # Verify run failed
+    assert result["ok"] is False
+    assert "Missing required field" in result["error"]
+    
+    # Verify nothing was written
+    if os.path.exists(config_fixture["store_path"]):
+        conn = sqlite3.connect(config_fixture["store_path"])
+        cursor = conn.execute("SELECT COUNT(*) FROM samples")
+        count = cursor.fetchone()[0]
+        assert count == 0
+        conn.close()
+    else:
+        # Store wasn't even created - also valid
+        pass
+
+
+# Test: Store initializes with six entities
+
+def test_store_initialization(config_fixture: Dict[str, Any]):
+    """Given no existing store,
+    when the collector runs,
+    then the store is initialized with six entities."""
+    store_path = Path(config_fixture["store_path"])
+    
+    # Store shouldn't exist yet
+    assert not store_path.exists()
+    
+    # Initialize store
+    conn = init_store(store_path)
+    
+    # Verify all six entities exist
+    cursor = conn.execute("SELECT name FROM sqlite_master WHERE type='table'")
+    tables = {row[0] for row in cursor.fetchall()}
+    
+    expected_tables = {
+        "samples",
+        "hour_observations",
+        "day_aggregates",
+        "monitoring_periods",
+        "controller_segments",
+        "endurance_baseline",
+    }
+    
+    # sqlite_sequence is a system table created by AUTOINCREMENT
+    expected_tables.add("sqlite_sequence")
+    expected_tables.add("store_metadata")
+    assert expected_tables == tables
+    
+    conn.close()
+
+
+# Test: Schema versioning with PRAGMA user_version
+
+def test_schema_versioning(config_fixture: Dict[str, Any]):
+    """Given a store with unknown newer version,
+    when the collector runs,
+    then it refuses to proceed."""
+    store_path = Path(config_fixture["store_path"])
+    
+    # Create a store with newer version
+    conn = sqlite3.connect(str(store_path))
+    conn.execute("PRAGMA journal_mode=WAL")
+    conn.execute("PRAGMA user_version=999")  # Unknown newer version
+    conn.close()
+    
+    # Try to initialize - should fail
+    with pytest.raises(ValueError, match="newer Fenris"):
+        init_store(store_path)
+
+
+def test_schema_version_current(config_fixture: Dict[str, Any]):
+    """Given a store with current version,
+    when the collector runs,
+    then it proceeds without migration."""
+    from fenris.store import SCHEMA_VERSION
+    
+    store_path = Path(config_fixture["store_path"])
+    
+    # Initialize store
+    conn1 = init_store(store_path)
+    conn1.close()
+    
+    # Open again - should succeed
+    conn2 = init_store(store_path)
+    
+    # Verify version is current
+    cursor = conn2.execute("PRAGMA user_version")
+    version = cursor.fetchone()[0]
+    assert version == SCHEMA_VERSION
+    
+    conn2.close()
+
+
+def test_schema_version_older(config_fixture: Dict[str, Any]):
+    """Given a store with older version,
+    when the collector runs,
+    then it applies migrations and proceeds."""
+    from fenris.store import SCHEMA_VERSION
+    
+    store_path = Path(config_fixture["store_path"])
+    
+    # Create a store with older version
+    conn = sqlite3.connect(str(store_path))
+    conn.execute("PRAGMA journal_mode=WAL")
+    conn.execute("PRAGMA user_version=0")  # Older version
+    conn.close()
+    
+    # Initialize store - should apply migrations
+    conn = init_store(store_path)
+    
+    # Verify version is current
+    cursor = conn.execute("PRAGMA user_version")
+    version = cursor.fetchone()[0]
+    assert version == SCHEMA_VERSION
+    
+    conn.close()
+
+
+# Test: Invariant-violating run writes nothing
+
+def test_invariant_violation_writes_nothing(
+    smartctl_fixture: Dict[str, Any],
+    sysfs_fixture_tree: Path,
+    config_fixture: Dict[str, Any],
+    clock_fixture,
+):
+    """Given a smartctl fixture that would violate store invariants,
+    when the collector runs,
+    then it writes nothing and fails visibly."""
+    # Create a fixture that would cause invariant violation
+    # (negative bytes_written - we'll mock this)
+    bad_smartctl = smartctl_fixture.copy()
+    bad_smartctl["nvme_smart_health_information_log"] = {
+        **smartctl_fixture["nvme_smart_health_information_log"],
+        "data_units_written": -1,  # This will cause negative bytes_written
+    }
+    
+    result = run_collection(
+        smartctl_data=bad_smartctl,
+        sysfs_path=sysfs_fixture_tree / "sys" / "class" / "nvme" / "nvme0",
+        config=config_fixture,
+        clock=clock_fixture,
+    )
+    
+    # Verify run failed
+    assert result["ok"] is False
+    assert "InvariantViolation" in result["error_type"]
+    
+    # Verify nothing was written
+    if os.path.exists(config_fixture["store_path"]):
+        conn = sqlite3.connect(config_fixture["store_path"])
+        cursor = conn.execute("SELECT COUNT(*) FROM samples")
+        count = cursor.fetchone()[0]
+        assert count == 0
+        conn.close()

tests/test_day_aggregates.py

@@ -0,0 +1,234 @@
+"""Day aggregate tests.
+
+From spec §5.4, §3.3, ST-4, ST-5:
+- One row per UTC day, derived monotonically from hour rows
+- No 23/25-hour days (UTC-bounded, DST never applies)
+- Coverage: share of wall-clock seconds inside monitoring periods
+  whose classification is known
+- No absent hour ever interpolated/estimated/fabricated (FL-3)
+"""
+import sqlite3
+import sys
+from datetime import datetime, timezone, timedelta
+from pathlib import Path
+
+import pytest
+
+sys.path.insert(0, str(Path(__file__).parent.parent / "src"))
+
+from fenris.store import init_store
+from fenris.monitoring_periods import ensure_period_open, close_period
+from fenris.day_aggregate import derive_day, derive_all_days, DayAggregate
+from fenris.hour_classify import HourSplit, ACTIVE_THRESHOLD_BYTES
+
+
+@pytest.fixture
+def store_conn(tmp_path: Path):
+    db_path = tmp_path / "test.db"
+    conn = init_store(db_path)
+    yield conn
+    conn.close()
+
+
+def _insert_hour(conn, hour_iso, split, bytes_written_delta=0, bytes_read_delta=0,
+                 sample_count=1, coverage=1.0):
+    conn.execute(
+        "INSERT INTO hour_observations "
+        "(hour, active_seconds, idle_seconds, powered_off_seconds, unknown_seconds, "
+        " bytes_written_delta, bytes_read_delta, sample_count, coverage) "
+        "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)",
+        (
+            hour_iso,
+            split.seconds_active,
+            split.seconds_idle,
+            split.seconds_powered_off,
+            split.seconds_unknown,
+            bytes_written_delta,
+            bytes_read_delta,
+            sample_count,
+            coverage,
+        ),
+    )
+    conn.commit()
+
+
+class TestDeriveDay:
+    """Spec §5.4: One row per UTC day, derived monotonically from hour rows."""
+
+    def test_single_hour_day(self, store_conn):
+        t_start = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        t_end = datetime(2026, 9, 1, 13, 0, 0, tzinfo=timezone.utc)
+        ensure_period_open(store_conn, t_start)
+        close_period(store_conn, t_end, "user_disabled")
+
+        hour = "2026-09-01T12:00:00+00:00"
+        split = HourSplit(seconds_active=3600, seconds_idle=0, seconds_powered_off=0, seconds_unknown=0)
+        _insert_hour(store_conn, hour, split, bytes_written_delta=1024*1024*100)
+
+        day = derive_day(store_conn, "2026-09-01")
+        assert day is not None
+        assert day.day == "2026-09-01"
+        assert day.seconds_active == 3600
+        assert day.seconds_idle == 0
+        assert day.seconds_powered_off == 0
+        assert day.bytes_written_delta == 1024*1024*100
+        assert day.sample_count == 1
+
+    def test_multiple_hours(self, store_conn):
+        t_start = datetime(2026, 9, 1, 10, 0, 0, tzinfo=timezone.utc)
+        t_end = datetime(2026, 9, 1, 13, 0, 0, tzinfo=timezone.utc)
+        ensure_period_open(store_conn, t_start)
+        close_period(store_conn, t_end, "user_disabled")
+
+        hours = [
+            ("2026-09-01T10:00:00+00:00", HourSplit(1800, 1800, 0, 0), 50*1024*1024),
+            ("2026-09-01T11:00:00+00:00", HourSplit(3600, 0, 0, 0), 200*1024*1024),
+            ("2026-09-01T12:00:00+00:00", HourSplit(0, 0, 3600, 0), 0),
+        ]
+        for h, s, bw in hours:
+            _insert_hour(store_conn, h, s, bytes_written_delta=bw)
+
+        day = derive_day(store_conn, "2026-09-01")
+        assert day is not None
+        assert day.seconds_active == 1800 + 3600 + 0
+        assert day.seconds_idle == 1800 + 0 + 0
+        assert day.seconds_powered_off == 0 + 0 + 3600
+        assert day.bytes_written_delta == 50*1024*1024 + 200*1024*1024 + 0
+        assert day.sample_count == 3
+
+    def test_no_hours_returns_none(self, store_conn):
+        day = derive_day(store_conn, "2026-09-01")
+        assert day is None
+
+
+class TestUtcBounded:
+    """Spec §3.3, ST-4: Hours and days are UTC-bounded. No 23/25-hour days."""
+
+    def test_day_keys_are_utc_date_strings(self, store_conn):
+        t_start = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        t_end = datetime(2026, 9, 1, 13, 0, 0, tzinfo=timezone.utc)
+        ensure_period_open(store_conn, t_start)
+        close_period(store_conn, t_end, "user_disabled")
+
+        hour = "2026-09-01T12:00:00+00:00"
+        split = HourSplit(0, 0, 3600, 0)
+        _insert_hour(store_conn, hour, split)
+
+        day = derive_day(store_conn, "2026-09-01")
+        assert day is not None
+        assert day.day == "2026-09-01"
+
+    def test_cross_midnight_hours_produce_two_days(self, store_conn):
+        # Period spans both days
+        t_start = datetime(2026, 9, 1, 23, 0, 0, tzinfo=timezone.utc)
+        t_end = datetime(2026, 9, 2, 1, 0, 0, tzinfo=timezone.utc)
+        ensure_period_open(store_conn, t_start)
+        close_period(store_conn, t_end, "user_disabled")
+
+        hours = [
+            ("2026-09-01T23:00:00+00:00", HourSplit(3600, 0, 0, 0), 100),
+            ("2026-09-02T00:00:00+00:00", HourSplit(0, 0, 3600, 0), 0),
+        ]
+        for h, s, bw in hours:
+            _insert_hour(store_conn, h, s, bytes_written_delta=bw)
+
+        days = derive_all_days(store_conn)
+        day_keys = [d.day for d in days]
+        assert "2026-09-01" in day_keys
+        assert "2026-09-02" in day_keys
+        assert len(days) == 2
+
+
+class TestCoverage:
+    """Spec §5.2, §5.3, PR-5: Coverage is known share of wall-clock seconds
+    inside monitoring periods."""
+
+    def test_full_coverage_all_known(self, store_conn):
+        """All hours in period classified -> coverage = 1.0."""
+        t_start = datetime(2026, 9, 1, 0, 0, 0, tzinfo=timezone.utc)
+        t_end = datetime(2026, 9, 1, 3, 0, 0, tzinfo=timezone.utc)
+        ensure_period_open(store_conn, t_start)
+        close_period(store_conn, t_end, "user_disabled")
+
+        hours = [
+            ("2026-09-01T00:00:00+00:00", HourSplit(3600, 0, 0, 0), 100),
+            ("2026-09-01T01:00:00+00:00", HourSplit(0, 3600, 0, 0), 50),
+            ("2026-09-01T02:00:00+00:00", HourSplit(0, 0, 3600, 0), 0),
+        ]
+        for h, s, bw in hours:
+            _insert_hour(store_conn, h, s, bytes_written_delta=bw)
+
+        day = derive_day(store_conn, "2026-09-01")
+        assert day is not None
+        assert day.coverage == pytest.approx(1.0)
+
+    def test_gap_reduces_coverage(self, store_conn):
+        """Missing hour -> unknown seconds reduce coverage."""
+        t_start = datetime(2026, 9, 1, 0, 0, 0, tzinfo=timezone.utc)
+        t_end = datetime(2026, 9, 1, 3, 0, 0, tzinfo=timezone.utc)
+        ensure_period_open(store_conn, t_start)
+        close_period(store_conn, t_end, "user_disabled")
+
+        _insert_hour(store_conn, "2026-09-01T00:00:00+00:00",
+                     HourSplit(3600, 0, 0, 0), bytes_written_delta=100)
+        _insert_hour(store_conn, "2026-09-01T02:00:00+00:00",
+                     HourSplit(0, 3600, 0, 0), bytes_written_delta=50)
+
+        day = derive_day(store_conn, "2026-09-01")
+        assert day is not None
+        assert day.coverage == pytest.approx(7200 / 10800)
+        assert day.seconds_unknown == 3600
+
+    def test_outside_period_excluded(self, store_conn):
+        """Hours outside any monitoring period excluded from denominator."""
+        t_start = datetime(2026, 9, 1, 1, 0, 0, tzinfo=timezone.utc)
+        t_end = datetime(2026, 9, 1, 2, 0, 0, tzinfo=timezone.utc)
+        ensure_period_open(store_conn, t_start)
+        close_period(store_conn, t_end, "user_disabled")
+
+        # Hour 01 is inside the period
+        _insert_hour(store_conn, "2026-09-01T01:00:00+00:00",
+                     HourSplit(3600, 0, 0, 0), bytes_written_delta=100)
+        # Hour 02 is outside (period ends at 02:00)
+        _insert_hour(store_conn, "2026-09-01T02:00:00+00:00",
+                     HourSplit(0, 3600, 0, 0), bytes_written_delta=50)
+
+        day = derive_day(store_conn, "2026-09-01")
+        assert day is not None
+        assert day.coverage == pytest.approx(1.0)
+
+    def test_unknown_in_period_reduces_coverage(self, store_conn):
+        """Unknown seconds inside period count in denominator but not numerator."""
+        t_start = datetime(2026, 9, 1, 0, 0, 0, tzinfo=timezone.utc)
+        t_end = datetime(2026, 9, 1, 1, 0, 0, tzinfo=timezone.utc)
+        ensure_period_open(store_conn, t_start)
+        close_period(store_conn, t_end, "user_disabled")
+
+        _insert_hour(store_conn, "2026-09-01T00:00:00+00:00",
+                     HourSplit(1800, 0, 0, 1800), bytes_written_delta=100)
+
+        day = derive_day(store_conn, "2026-09-01")
+        assert day is not None
+        assert day.coverage == pytest.approx(0.5)
+        assert day.seconds_unknown == 1800
+
+
+class TestNoFabrication:
+    """Spec §5.3, FL-3: No absent hour is ever interpolated/estimated/fabricated."""
+
+    def test_missing_hours_stay_unknown(self, store_conn):
+        """Gap hours are never filled in — they remain as unknown seconds."""
+        t_start = datetime(2026, 9, 1, 0, 0, 0, tzinfo=timezone.utc)
+        t_end = datetime(2026, 9, 1, 3, 0, 0, tzinfo=timezone.utc)
+        ensure_period_open(store_conn, t_start)
+        close_period(store_conn, t_end, "user_disabled")
+
+        # Only hour 02 — hours 00 and 01 are gaps
+        _insert_hour(store_conn, "2026-09-01T02:00:00+00:00",
+                     HourSplit(3600, 0, 0, 0), bytes_written_delta=100)
+
+        day = derive_day(store_conn, "2026-09-01")
+        assert day is not None
+        assert day.seconds_unknown == 2 * 3600
+        assert day.seconds_active == 3600
+        assert day.sample_count == 1

tests/test_hour_classification.py

@@ -0,0 +1,218 @@
+"""Hour classification tests.
+
+From spec §5.1 — each UTC hour is classified by named constants:
+- Powered-off: power-on-hours delta < 90% of wall-clock span
+- Active: DUW delta >= 256 MiB
+- Idle: powered on + sampled + below active threshold
+- Unknown: everything else
+
+Four splits sum to exactly 3600s. Disabled time is never an hour state.
+"""
+import sys
+from pathlib import Path
+
+import pytest
+
+sys.path.insert(0, str(Path(__file__).parent.parent / "src"))
+
+from fenris.hour_classify import classify_hour, HourSplit, ACTIVE_THRESHOLD_BYTES
+
+HOUR_SECONDS = 3600
+
+
+class TestPoweredOff:
+    """Spec §5.1: Powered-off when power-on-hours delta < 90% of wall-clock span."""
+
+    def test_below_90_percent_poh_is_powered_off(self):
+        split = classify_hour(
+            wall_clock_seconds=HOUR_SECONDS,
+            poh_delta=0,
+            duw_delta=0,
+            dur_delta=0,
+        )
+        assert split.seconds_powered_off == HOUR_SECONDS
+        assert split.seconds_active == 0
+        assert split.seconds_idle == 0
+        assert split.seconds_unknown == 0
+
+    def test_exactly_90_percent_poh_is_not_powered_off(self):
+        split = classify_hour(
+            wall_clock_seconds=HOUR_SECONDS,
+            poh_delta=3240,
+            duw_delta=0,
+            dur_delta=0,
+        )
+        assert split.seconds_powered_off == 0
+        assert split.seconds_unknown == HOUR_SECONDS
+
+    def test_just_below_90_percent_poh_is_powered_off(self):
+        split = classify_hour(
+            wall_clock_seconds=HOUR_SECONDS,
+            poh_delta=3239,
+            duw_delta=0,
+            dur_delta=0,
+        )
+        assert split.seconds_powered_off == HOUR_SECONDS
+
+    def test_100_percent_poh_is_not_powered_off(self):
+        split = classify_hour(
+            wall_clock_seconds=HOUR_SECONDS,
+            poh_delta=HOUR_SECONDS,
+            duw_delta=0,
+            dur_delta=0,
+        )
+        assert split.seconds_powered_off == 0
+
+
+class TestActive:
+    """Spec §5.1: Active when DUW delta >= 256 MiB."""
+
+    def test_above_256_mib_is_active(self):
+        split = classify_hour(
+            wall_clock_seconds=HOUR_SECONDS,
+            poh_delta=HOUR_SECONDS,
+            duw_delta=ACTIVE_THRESHOLD_BYTES,
+            dur_delta=1000,
+            sampled_seconds=HOUR_SECONDS,
+        )
+        assert split.seconds_active == HOUR_SECONDS
+
+    def test_just_below_256_mib_is_idle(self):
+        split = classify_hour(
+            wall_clock_seconds=HOUR_SECONDS,
+            poh_delta=HOUR_SECONDS,
+            duw_delta=ACTIVE_THRESHOLD_BYTES - 1,
+            dur_delta=1000,
+            sampled_seconds=HOUR_SECONDS,
+        )
+        assert split.seconds_idle == HOUR_SECONDS
+        assert split.seconds_active == 0
+
+    def test_powered_off_takes_priority_over_active_writes(self):
+        """Spec §5.1 order: powered-off checked first."""
+        split = classify_hour(
+            wall_clock_seconds=HOUR_SECONDS,
+            poh_delta=0,
+            duw_delta=ACTIVE_THRESHOLD_BYTES,
+            dur_delta=1000,
+        )
+        assert split.seconds_powered_off == HOUR_SECONDS
+        assert split.seconds_active == 0
+
+
+class TestIdle:
+    """Spec §5.1: Idle when powered on, sampled, below active threshold."""
+
+    def test_idle_with_writes_below_threshold(self):
+        split = classify_hour(
+            wall_clock_seconds=HOUR_SECONDS,
+            poh_delta=HOUR_SECONDS,
+            duw_delta=1024 * 1024,  # 1 MiB
+            dur_delta=500,
+            sampled_seconds=HOUR_SECONDS,
+        )
+        assert split.seconds_idle == HOUR_SECONDS
+        assert split.seconds_active == 0
+
+    def test_idle_no_writes(self):
+        """Powered on, sampled, zero writes -> idle."""
+        split = classify_hour(
+            wall_clock_seconds=HOUR_SECONDS,
+            poh_delta=HOUR_SECONDS,
+            duw_delta=0,
+            dur_delta=0,
+            sampled_seconds=HOUR_SECONDS,
+        )
+        assert split.seconds_idle == HOUR_SECONDS
+
+
+class TestUnknown:
+    """Spec §5.1: Unknown when unsampled without POH evidence."""
+
+    def test_no_sample_no_writes_is_unknown(self):
+        split = classify_hour(
+            wall_clock_seconds=HOUR_SECONDS,
+            poh_delta=HOUR_SECONDS,
+            duw_delta=0,
+            dur_delta=0,
+        )
+        assert split.seconds_unknown == HOUR_SECONDS
+
+    def test_partial_unknown(self):
+        """Partial hour -> split unknown for unsampled portion."""
+        split = classify_hour(
+            wall_clock_seconds=HOUR_SECONDS,
+            poh_delta=HOUR_SECONDS,
+            duw_delta=0,
+            dur_delta=0,
+            sampled_seconds=1800,
+        )
+        assert split.seconds_unknown == 1800
+        assert split.seconds_idle == 1800
+
+    def test_powered_off_with_no_sample_still_powered_off(self):
+        """POH < 90% is powered off regardless of sample status."""
+        split = classify_hour(
+            wall_clock_seconds=HOUR_SECONDS,
+            poh_delta=0,
+            duw_delta=0,
+            dur_delta=0,
+            sampled_seconds=0,
+        )
+        assert split.seconds_powered_off == HOUR_SECONDS
+        assert split.seconds_unknown == 0
+
+
+class TestSumTo3600:
+    """Spec §5.1: Four splits sum to exactly wall_clock_seconds."""
+
+    def test_all_scenarios_sum_to_wall_clock(self):
+        scenarios = [
+            {"wall_clock_seconds": 3600, "poh_delta": 0, "duw_delta": 0, "dur_delta": 0},
+            {"wall_clock_seconds": 3600, "poh_delta": 3600, "duw_delta": 0, "dur_delta": 0},
+            {"wall_clock_seconds": 3600, "poh_delta": 3600, "duw_delta": ACTIVE_THRESHOLD_BYTES, "dur_delta": 1000, "sampled_seconds": 3600},
+            {"wall_clock_seconds": 3600, "poh_delta": 3600, "duw_delta": 1000, "dur_delta": 500, "sampled_seconds": 3600},
+            {"wall_clock_seconds": 3600, "poh_delta": 3239, "duw_delta": 0, "dur_delta": 0},
+            {"wall_clock_seconds": 1800, "poh_delta": 0, "duw_delta": 0, "dur_delta": 0},
+            {"wall_clock_seconds": 3600, "poh_delta": 3600, "duw_delta": 0, "dur_delta": 0, "sampled_seconds": 1800},
+        ]
+        for s in scenarios:
+            split = classify_hour(**s)
+            total = (
+                split.seconds_active
+                + split.seconds_idle
+                + split.seconds_powered_off
+                + split.seconds_unknown
+            )
+            assert total == s["wall_clock_seconds"], (
+                f"Scenario {s}: splits sum to {total}, expected {s['wall_clock_seconds']}"
+            )
+
+    def test_partial_wall_clock(self):
+        split = classify_hour(
+            wall_clock_seconds=1800,
+            poh_delta=0,
+            duw_delta=0,
+            dur_delta=0,
+        )
+        total = (
+            split.seconds_active
+            + split.seconds_idle
+            + split.seconds_powered_off
+            + split.seconds_unknown
+        )
+        assert total == 1800
+        assert split.seconds_powered_off == 1800
+
+
+class TestDisabledTimeNotAnHourState:
+    """Spec §5.2: Disabled time is not an hour state — excluded from numerator/denominator."""
+
+    def test_classify_hour_has_no_disabled_state(self):
+        split = classify_hour(
+            wall_clock_seconds=HOUR_SECONDS,
+            poh_delta=0,
+            duw_delta=0,
+            dur_delta=0,
+        )
+        assert not hasattr(split, "seconds_disabled")

tests/test_identity_normalization.py

@@ -0,0 +1,96 @@
+"""Test identity normalization per specification.
+
+From spec §2.3:
+- strip trailing spaces and newlines
+- no case folding
+- empty-after-strip stored blank
+
+Padded and unpadded renderings of the same field yield byte-identical stored values.
+"""
+import pytest
+import sys
+from pathlib import Path
+
+sys.path.insert(0, str(Path(__file__).parent.parent / "src"))
+
+from fenris.collector import normalize_identity
+
+
+def test_strip_trailing_spaces():
+    """Trailing spaces are stripped."""
+    identity = {"subnqn": "nqn.2014-08.org.nvmexpress:uuid:12345678  "}
+    result = normalize_identity(identity)
+    assert result == "nqn.2014-08.org.nvmexpress:uuid:12345678"
+
+
+def test_strip_trailing_newlines():
+    """Trailing newlines are stripped."""
+    identity = {"subnqn": "nqn.2014-08.org.nvmexpress:uuid:12345678\n"}
+    result = normalize_identity(identity)
+    assert result == "nqn.2014-08.org.nvmexpress:uuid:12345678"
+
+
+def test_strip_trailing_spaces_and_newlines():
+    """Trailing spaces and newlines are stripped."""
+    identity = {"subnqn": "nqn.2014-08.org.nvmexpress:uuid:12345678  \n\n"}
+    result = normalize_identity(identity)
+    assert result == "nqn.2014-08.org.nvmexpress:uuid:12345678"
+
+
+def test_no_case_folding():
+    """Case is preserved - no case folding."""
+    identity = {"subnqn": "NQN.2014-08.ORG.NVMEXPRESS:UUID:12345678"}
+    result = normalize_identity(identity)
+    assert result == "NQN.2014-08.ORG.NVMEXPRESS:UUID:12345678"
+
+
+def test_empty_after_strip_stored_blank():
+    """Empty after strip is stored as blank string."""
+    identity = {"subnqn": "   \n\n  "}
+    result = normalize_identity(identity)
+    assert result == ""
+
+
+def test_fallback_to_model_serial():
+    """When subnqn is empty, falls back to model|serial."""
+    identity = {
+        "subnqn": "",
+        "mn": "Samsung SSD 970 EVO Plus 1TB",
+        "sn": "S4EWNX0N123456",
+    }
+    result = normalize_identity(identity)
+    assert result == "Samsung SSD 970 EVO Plus 1TB|S4EWNX0N123456"
+
+
+def test_fallback_model_serial_normalized():
+    """Model and serial are also normalized."""
+    identity = {
+        "subnqn": "",
+        "mn": "Samsung SSD 970 EVO Plus 1TB\n",
+        "sn": "S4EWNX0N123456  ",
+    }
+    result = normalize_identity(identity)
+    assert result == "Samsung SSD 970 EVO Plus 1TB|S4EWNX0N123456"
+
+
+def test_all_keys_blank_returns_blank():
+    """When all keys are blank, returns blank (degraded identity)."""
+    identity = {
+        "subnqn": "",
+        "mn": "",
+        "sn": "",
+    }
+    result = normalize_identity(identity)
+    assert result == ""
+
+
+def test_byte_identical_for_padded_unpadded():
+    """Padded and unpadded renderings yield byte-identical values."""
+    padded = {"subnqn": "nqn.2014-08.org.nvmexpress:uuid:12345678  \n"}
+    unpadded = {"subnqn": "nqn.2014-08.org.nvmexpress:uuid:12345678"}
+    
+    result_padded = normalize_identity(padded)
+    result_unpadded = normalize_identity(unpadded)
+    
+    assert result_padded == result_unpadded
+    assert result_padded == "nqn.2014-08.org.nvmexpress:uuid:12345678"

tests/test_init_system.py

@@ -0,0 +1,659 @@
+"""Tests for the init system abstraction layer (issue #84).
+
+Covers:
+  - Init system detection (systemd vs runit)
+  - systemd backend functions (enable, disable, collect, query state)
+  - runit backend functions (enable, disable, collect, query state)
+  - Public API dispatching to correct backend
+  - Edge cases (already enabled/disabled, missing files, timeouts)
+
+Spec: ADR 0008, §8.4, §8.5, §8.6, §8.7, §8.8
+"""
+import os
+import sqlite3
+import tempfile
+from datetime import datetime, timedelta, timezone
+from pathlib import Path
+from unittest.mock import patch, MagicMock, PropertyMock
+
+import pytest
+
+import sys
+sys.path.insert(0, str(Path(__file__).parent.parent / "src"))
+
+from fenris.init_system import (
+    InitSystem,
+    detect_init_system,
+    get_init_system,
+    reset_init_system_cache,
+    _systemd_enable,
+    _systemd_disable,
+    _systemd_collect,
+    _systemd_query_state,
+    _runit_enable,
+    _runit_disable,
+    _runit_collect,
+    _runit_query_state,
+    _runit_is_enabled,
+    _runit_is_running,
+    enable_timer,
+    disable_timer,
+    collect_now,
+    query_service_state,
+    journal_hint,
+    FENRIS_SV_DIR,
+    FENRIS_SERVICE_LINK,
+    COLLECT_TIMEOUT_S,
+)
+from fenris.store import init_store
+
+
+@pytest.fixture(autouse=True)
+def reset_cache():
+    """Reset the init system cache before each test."""
+    reset_init_system_cache()
+    yield
+    reset_init_system_cache()
+
+
+# ---------------------------------------------------------------------------
+# Init system detection
+# ---------------------------------------------------------------------------
+
+class TestInitSystemDetection:
+    """Test init system detection logic."""
+
+    def test_detect_systemd_by_run_directory(self):
+        """Systemd detected via /run/systemd/system directory."""
+        with patch("pathlib.Path.exists") as mock_exists:
+            mock_exists.return_value = True
+            reset_init_system_cache()
+            result = detect_init_system()
+            assert result == InitSystem.SYSTEMD
+
+    def test_detect_systemd_by_pid1(self):
+        """Systemd detected via PID 1 name."""
+        original_exists = Path.exists
+        original_read_text = Path.read_text
+
+        def mock_exists(self_path):
+            if str(self_path) == "/run/systemd/system":
+                return False
+            return original_exists(self_path)
+
+        def mock_read_text(self_path):
+            if str(self_path) == "/proc/1/comm":
+                return "systemd"
+            return original_read_text(self_path)
+
+        with patch("pathlib.Path.exists", mock_exists), \
+             patch("pathlib.Path.read_text", mock_read_text):
+            reset_init_system_cache()
+            result = detect_init_system()
+            assert result == InitSystem.SYSTEMD
+
+    def test_detect_runit_by_pid1(self):
+        """Runit detected via PID 1 name."""
+        original_exists = Path.exists
+        original_read_text = Path.read_text
+
+        def mock_exists(self_path):
+            if str(self_path) == "/run/systemd/system":
+                return False
+            return original_exists(self_path)
+
+        def mock_read_text(self_path):
+            if str(self_path) == "/proc/1/comm":
+                return "runsv"
+            return original_read_text(self_path)
+
+        with patch("pathlib.Path.exists", mock_exists), \
+             patch("pathlib.Path.read_text", mock_read_text):
+            reset_init_system_cache()
+            result = detect_init_system()
+            assert result == InitSystem.RUNIT
+
+    def test_detect_runit_by_etc_sv(self):
+        """Runit detected via /etc/sv directory."""
+        original_exists = Path.exists
+        original_read_text = Path.read_text
+
+        def mock_exists(self_path):
+            if str(self_path) == "/run/systemd/system":
+                return False
+            if str(self_path) == "/etc/sv":
+                return True
+            return original_exists(self_path)
+
+        def mock_read_text(self_path):
+            if str(self_path) == "/proc/1/comm":
+                raise OSError("no such file")
+            return original_read_text(self_path)
+
+        with patch("pathlib.Path.exists", mock_exists), \
+             patch("pathlib.Path.read_text", mock_read_text):
+            reset_init_system_cache()
+            result = detect_init_system()
+            assert result == InitSystem.RUNIT
+
+    def test_default_to_systemd(self):
+        """Default to systemd when no detection matches."""
+        original_exists = Path.exists
+        original_read_text = Path.read_text
+        original_is_dir = Path.is_dir
+
+        def mock_exists(self_path):
+            if str(self_path) == "/run/systemd/system":
+                return False
+            return original_exists(self_path)
+
+        def mock_is_dir(self_path):
+            if str(self_path) == "/etc/sv":
+                return False
+            return original_is_dir(self_path)
+
+        def mock_read_text(self_path):
+            if str(self_path) == "/proc/1/comm":
+                raise OSError("no such file")
+            return original_read_text(self_path)
+
+        with patch("pathlib.Path.exists", mock_exists), \
+             patch("pathlib.Path.is_dir", mock_is_dir), \
+             patch("pathlib.Path.read_text", mock_read_text):
+            reset_init_system_cache()
+            result = detect_init_system()
+            assert result == InitSystem.SYSTEMD
+
+
+# ---------------------------------------------------------------------------
+# systemd backend
+# ---------------------------------------------------------------------------
+
+class TestSystemdEnable:
+    """Test systemd enable function."""
+
+    def test_enable_now(self):
+        """Enable with --now flag."""
+        with patch("fenris.init_system.subprocess") as mock_sub:
+            mock_sub.run.return_value = MagicMock(returncode=0)
+            _systemd_enable(now=True)
+            mock_sub.run.assert_called_once_with(
+                ["systemctl", "enable", "--now", "fenris-collect.timer"],
+                capture_output=True, text=True,
+            )
+
+    def test_enable_without_now(self):
+        """Enable without --now flag."""
+        with patch("fenris.init_system.subprocess") as mock_sub:
+            mock_sub.run.return_value = MagicMock(returncode=0)
+            _systemd_enable(now=False)
+            mock_sub.run.assert_called_once_with(
+                ["systemctl", "enable", "fenris-collect.timer"],
+                capture_output=True, text=True,
+            )
+
+    def test_enable_failure_exits(self):
+        """Enable failure exits with error."""
+        with patch("fenris.init_system.subprocess") as mock_sub:
+            mock_sub.run.return_value = MagicMock(
+                returncode=1, stderr="Unit not found"
+            )
+            with pytest.raises(SystemExit) as exc_info:
+                _systemd_enable(now=True)
+            assert exc_info.value.code == 1
+
+
+class TestSystemdDisable:
+    """Test systemd disable function."""
+
+    def test_disable_now(self):
+        """Disable with --now flag."""
+        with patch("fenris.init_system.subprocess") as mock_sub:
+            mock_sub.run.return_value = MagicMock(returncode=0)
+            _systemd_disable(now=True)
+            mock_sub.run.assert_called_once_with(
+                ["systemctl", "disable", "--now", "fenris-collect.timer"],
+                capture_output=True, text=True,
+            )
+
+    def test_disable_without_now(self):
+        """Disable without --now flag."""
+        with patch("fenris.init_system.subprocess") as mock_sub:
+            mock_sub.run.return_value = MagicMock(returncode=0)
+            _systemd_disable(now=False)
+            mock_sub.run.assert_called_once_with(
+                ["systemctl", "disable", "fenris-collect.timer"],
+                capture_output=True, text=True,
+            )
+
+
+class TestSystemdCollect:
+    """Test systemd collect function."""
+
+    def test_collect_success(self):
+        """Successful collection."""
+        with patch("fenris.init_system.subprocess") as mock_sub:
+            mock_sub.run.return_value = MagicMock(returncode=0)
+            _systemd_collect()
+            mock_sub.run.assert_called_once_with(
+                ["systemctl", "start", "fenris-collect.service"],
+                capture_output=True, text=True,
+            )
+
+    def test_collect_failure_exits(self):
+        """Collection failure exits with error."""
+        with patch("fenris.init_system.subprocess") as mock_sub:
+            mock_sub.run.return_value = MagicMock(
+                returncode=1, stderr="Unit not found"
+            )
+            with pytest.raises(SystemExit) as exc_info:
+                _systemd_collect()
+            assert exc_info.value.code == 1
+
+
+class TestSystemdQueryState:
+    """Test systemd query state function."""
+
+    def test_query_state_enabled_active(self):
+        """Query state for enabled and active timer."""
+        with patch("fenris.init_system._systemctl_show") as mock_show:
+            def mock_show_fn(unit, *props):
+                if unit == "fenris-collect.timer":
+                    return {
+                        "UnitFileState": "enabled",
+                        "ActiveState": "active",
+                        "LastTriggerUSec": "2026-09-01T12:00:00Z",
+                    }
+                elif unit == "fenris-collect.service":
+                    return {
+                        "ActiveState": "inactive",
+                        "ExecMainStatus": "0",
+                        "ExecMainExitTimestamp": "2026-09-01T12:00:30Z",
+                    }
+                return {}
+            mock_show.side_effect = mock_show_fn
+
+            result = _systemd_query_state()
+
+            assert result["boot_enabled"] is True
+            assert result["timer_active"] is True
+            assert result["last_collect_ok"] is True
+            assert result["last_collect_age_s"] is not None
+
+    def test_query_state_disabled_inactive(self):
+        """Query state for disabled and inactive timer."""
+        with patch("fenris.init_system._systemctl_show") as mock_show:
+            mock_show.return_value = {}
+            result = _systemd_query_state()
+            assert result["boot_enabled"] is False
+            assert result["timer_active"] is False
+            assert result["last_collect_ok"] is None
+
+
+# ---------------------------------------------------------------------------
+# runit backend
+# ---------------------------------------------------------------------------
+
+class TestRunitEnable:
+    """Test runit enable function."""
+
+    def test_enable_creates_symlink(self, tmp_path):
+        """Enable creates symlink to service directory."""
+        sv_dir = tmp_path / "sv" / "fenris-collect"
+        sv_dir.mkdir(parents=True)
+        service_link = tmp_path / "service" / "fenris-collect"
+        service_link.parent.mkdir(parents=True)
+
+        with patch("fenris.init_system.FENRIS_SV_DIR", sv_dir), \
+             patch("fenris.init_system.FENRIS_SERVICE_LINK", service_link):
+            _runit_enable(_now=True)
+            assert service_link.exists()
+            assert service_link.is_symlink()
+            assert service_link.resolve() == sv_dir
+
+    def test_enable_removes_down_file(self, tmp_path):
+        """Enable removes the 'down' file if present."""
+        sv_dir = tmp_path / "sv" / "fenris-collect"
+        sv_dir.mkdir(parents=True)
+        (sv_dir / "down").touch()
+        service_link = tmp_path / "service" / "fenris-collect"
+        service_link.parent.mkdir(parents=True)
+
+        with patch("fenris.init_system.FENRIS_SV_DIR", sv_dir), \
+             patch("fenris.init_system.FENRIS_SERVICE_LINK", service_link):
+            _runit_enable(_now=True)
+            assert not (sv_dir / "down").exists()
+
+    def test_enable_idempotent(self, tmp_path):
+        """Enable is idempotent when already enabled."""
+        sv_dir = tmp_path / "sv" / "fenris-collect"
+        sv_dir.mkdir(parents=True)
+        service_link = tmp_path / "service" / "fenris-collect"
+        service_link.parent.mkdir(parents=True)
+        service_link.symlink_to(sv_dir)
+
+        with patch("fenris.init_system.FENRIS_SV_DIR", sv_dir), \
+             patch("fenris.init_system.FENRIS_SERVICE_LINK", service_link):
+            _runit_enable(_now=True)
+            assert service_link.exists()
+
+
+class TestRunitDisable:
+    """Test runit disable function."""
+
+    def test_disable_removes_symlink(self, tmp_path):
+        """Disable removes the service symlink."""
+        sv_dir = tmp_path / "sv" / "fenris-collect"
+        sv_dir.mkdir(parents=True)
+        service_link = tmp_path / "service" / "fenris-collect"
+        service_link.parent.mkdir(parents=True)
+        service_link.symlink_to(sv_dir)
+
+        with patch("fenris.init_system.FENRIS_SV_DIR", sv_dir), \
+             patch("fenris.init_system.FENRIS_SERVICE_LINK", service_link):
+            _runit_disable(_now=True)
+            assert not service_link.exists()
+            assert (sv_dir / "down").exists()
+
+    def test_disable_idempotent(self, tmp_path):
+        """Disable is idempotent when already disabled."""
+        sv_dir = tmp_path / "sv" / "fenris-collect"
+        sv_dir.mkdir(parents=True)
+        service_link = tmp_path / "service" / "fenris-collect"
+        service_link.parent.mkdir(parents=True)
+
+        with patch("fenris.init_system.FENRIS_SV_DIR", sv_dir), \
+             patch("fenris.init_system.FENRIS_SERVICE_LINK", service_link):
+            _runit_disable(_now=True)
+            assert not service_link.exists()
+
+
+class TestRunitCollect:
+    """Test runit collect function."""
+
+    def test_collect_uses_flock(self):
+        """Collect uses flock for serialization."""
+        with patch("fenris.init_system.subprocess") as mock_sub, \
+             patch("fenris.init_system.Path") as mock_path:
+            mock_path.return_value.exists.return_value = True
+            mock_sub.run.return_value = MagicMock(returncode=0)
+            _runit_collect()
+            # Verify flock was used
+            call_args = mock_sub.run.call_args[0][0]
+            assert "flock" in call_args
+
+    def test_collect_timeout_exits(self):
+        """Collection timeout exits with error."""
+        with patch("fenris.init_system.subprocess") as mock_sub, \
+             patch("fenris.init_system.Path") as mock_path:
+            mock_path.return_value.exists.return_value = True
+            mock_sub.run.return_value = MagicMock(returncode=124)
+            with pytest.raises(SystemExit) as exc_info:
+                _runit_collect()
+            assert exc_info.value.code == 1
+
+
+class TestRunitQueryState:
+    """Test runit query state function."""
+
+    def test_query_state_enabled_running(self, tmp_path):
+        """Query state for enabled and running service."""
+        sv_dir = tmp_path / "sv" / "fenris-collect"
+        sv_dir.mkdir(parents=True)
+        supervise_dir = sv_dir / "supervise"
+        supervise_dir.mkdir(parents=True)
+        (supervise_dir / "pid").write_text("12345")
+        service_link = tmp_path / "service" / "fenris-collect"
+        service_link.parent.mkdir(parents=True)
+        service_link.symlink_to(sv_dir)
+
+        with patch("fenris.init_system.FENRIS_SV_DIR", sv_dir), \
+             patch("fenris.init_system.FENRIS_SERVICE_LINK", service_link), \
+             patch("os.kill") as mock_kill:
+            mock_kill.return_value = True  # Process exists
+            result = _runit_query_state()
+            assert result["boot_enabled"] is True
+            assert result["timer_active"] is True
+
+    def test_query_state_disabled_not_running(self, tmp_path):
+        """Query state for disabled and not running service."""
+        sv_dir = tmp_path / "sv" / "fenris-collect"
+        sv_dir.mkdir(parents=True)
+        service_link = tmp_path / "service" / "fenris-collect"
+        service_link.parent.mkdir(parents=True)
+
+        with patch("fenris.init_system.FENRIS_SV_DIR", sv_dir), \
+             patch("fenris.init_system.FENRIS_SERVICE_LINK", service_link):
+            result = _runit_query_state()
+            assert result["boot_enabled"] is False
+            assert result["timer_active"] is False
+
+
+class TestRunitIsEnabled:
+    """Test runit is_enabled check."""
+
+    def test_is_enabled_true(self, tmp_path):
+        """Service is enabled when symlink exists."""
+        sv_dir = tmp_path / "sv" / "fenris-collect"
+        sv_dir.mkdir(parents=True)
+        service_link = tmp_path / "service" / "fenris-collect"
+        service_link.parent.mkdir(parents=True)
+        service_link.symlink_to(sv_dir)
+
+        with patch("fenris.init_system.FENRIS_SERVICE_LINK", service_link):
+            assert _runit_is_enabled() is True
+
+    def test_is_enabled_false(self, tmp_path):
+        """Service is disabled when symlink does not exist."""
+        service_link = tmp_path / "service" / "fenris-collect"
+
+        with patch("fenris.init_system.FENRIS_SERVICE_LINK", service_link):
+            assert _runit_is_enabled() is False
+
+
+class TestRunitIsRunning:
+    """Test runit is_running check."""
+
+    def test_is_running_true(self, tmp_path):
+        """Service is running when PID file exists and process is alive."""
+        sv_dir = tmp_path / "sv" / "fenris-collect"
+        supervise_dir = sv_dir / "supervise"
+        supervise_dir.mkdir(parents=True)
+        (supervise_dir / "pid").write_text("12345")
+
+        with patch("fenris.init_system.FENRIS_SV_DIR", sv_dir), \
+             patch("os.kill") as mock_kill:
+            mock_kill.return_value = True
+            assert _runit_is_running() is True
+
+    def test_is_running_false_no_pid(self, tmp_path):
+        """Service is not running when PID file does not exist."""
+        sv_dir = tmp_path / "sv" / "fenris-collect"
+        sv_dir.mkdir(parents=True)
+
+        with patch("fenris.init_system.FENRIS_SV_DIR", sv_dir):
+            assert _runit_is_running() is False
+
+    def test_is_running_false_dead_process(self, tmp_path):
+        """Service is not running when process is dead."""
+        sv_dir = tmp_path / "sv" / "fenris-collect"
+        supervise_dir = sv_dir / "supervise"
+        supervise_dir.mkdir(parents=True)
+        (supervise_dir / "pid").write_text("12345")
+
+        with patch("fenris.init_system.FENRIS_SV_DIR", sv_dir), \
+             patch("os.kill", side_effect=OSError("No such process")):
+            assert _runit_is_running() is False
+
+
+# ---------------------------------------------------------------------------
+# Public API dispatching
+# ---------------------------------------------------------------------------
+
+class TestPublicAPI:
+    """Test public API dispatches to correct backend."""
+
+    def test_enable_dispatches_to_systemd(self):
+        """enable_timer dispatches to systemd on systemd system."""
+        with patch("fenris.init_system.get_init_system", return_value=InitSystem.SYSTEMD), \
+             patch("fenris.init_system._systemd_enable") as mock_enable:
+            enable_timer(now=True)
+            mock_enable.assert_called_once_with(True)
+
+    def test_enable_dispatches_to_runit(self):
+        """enable_timer dispatches to runit on runit system."""
+        with patch("fenris.init_system.get_init_system", return_value=InitSystem.RUNIT), \
+             patch("fenris.init_system._runit_enable") as mock_enable:
+            enable_timer(now=True)
+            mock_enable.assert_called_once_with(True)
+
+    def test_disable_dispatches_to_systemd(self):
+        """disable_timer dispatches to systemd on systemd system."""
+        with patch("fenris.init_system.get_init_system", return_value=InitSystem.SYSTEMD), \
+             patch("fenris.init_system._systemd_disable") as mock_disable:
+            disable_timer(now=False)
+            mock_disable.assert_called_once_with(False)
+
+    def test_disable_dispatches_to_runit(self):
+        """disable_timer dispatches to runit on runit system."""
+        with patch("fenris.init_system.get_init_system", return_value=InitSystem.RUNIT), \
+             patch("fenris.init_system._runit_disable") as mock_disable:
+            disable_timer(now=False)
+            mock_disable.assert_called_once_with(False)
+
+    def test_collect_dispatches_to_systemd(self):
+        """collect_now dispatches to systemd on systemd system."""
+        with patch("fenris.init_system.get_init_system", return_value=InitSystem.SYSTEMD), \
+             patch("fenris.init_system._systemd_collect") as mock_collect:
+            collect_now()
+            mock_collect.assert_called_once()
+
+    def test_collect_dispatches_to_runit(self):
+        """collect_now dispatches to runit on runit system."""
+        with patch("fenris.init_system.get_init_system", return_value=InitSystem.RUNIT), \
+             patch("fenris.init_system._runit_collect") as mock_collect:
+            collect_now()
+            mock_collect.assert_called_once()
+
+    def test_query_state_dispatches_to_systemd(self):
+        """query_service_state dispatches to systemd on systemd system."""
+        with patch("fenris.init_system.get_init_system", return_value=InitSystem.SYSTEMD), \
+             patch("fenris.init_system._systemd_query_state") as mock_query:
+            query_service_state()
+            mock_query.assert_called_once()
+
+    def test_query_state_dispatches_to_runit(self):
+        """query_service_state dispatches to runit on runit system."""
+        with patch("fenris.init_system.get_init_system", return_value=InitSystem.RUNIT), \
+             patch("fenris.init_system._runit_query_state") as mock_query:
+            query_service_state()
+            mock_query.assert_called_once()
+
+    def test_journal_hint_dispatches_to_systemd(self):
+        """journal_hint dispatches to systemd on systemd system."""
+        with patch("fenris.init_system.get_init_system", return_value=InitSystem.SYSTEMD), \
+             patch("fenris.init_system._systemd_journal_hint") as mock_hint:
+            journal_hint(lines=3, unit="fenris-collect.service")
+            mock_hint.assert_called_once_with(3)
+
+    def test_journal_hint_dispatches_to_runit(self):
+        """journal_hint dispatches to runit on runit system."""
+        with patch("fenris.init_system.get_init_system", return_value=InitSystem.RUNIT), \
+             patch("fenris.init_system._runit_journal_hint") as mock_hint:
+            journal_hint(lines=3, unit="fenris-collect.service")
+            mock_hint.assert_called_once_with(3)
+
+
+# ---------------------------------------------------------------------------
+# Constants and configuration
+# ---------------------------------------------------------------------------
+
+class TestConstants:
+    """Test constants match spec requirements."""
+
+    def test_collect_timeout(self):
+        """Collection timeout is 90 seconds (bounded execution)."""
+        assert COLLECT_TIMEOUT_S == 90
+
+    def test_init_system_enum(self):
+        """InitSystem enum has systemd and runit variants."""
+        assert InitSystem.SYSTEMD.value == "systemd"
+        assert InitSystem.RUNIT.value == "runit"
+
+
+# ---------------------------------------------------------------------------
+# Integration with monitor.py
+# ---------------------------------------------------------------------------
+
+class TestMonitorIntegration:
+    """Test that monitor.py uses the abstraction layer correctly."""
+
+    def test_cmd_enable_uses_init_system(self, tmp_path):
+        """cmd_enable uses init_system.enable_timer."""
+        from fenris.monitor import cmd_enable
+        from argparse import Namespace
+
+        store_path = tmp_path / "observations.db"
+        init_store(store_path)
+        args = Namespace(now=True, store_path=store_path)
+
+        with patch("fenris.monitor.enable_timer") as mock_enable:
+            cmd_enable(args)
+            mock_enable.assert_called_once_with(True)
+
+    def test_cmd_disable_uses_init_system(self, tmp_path):
+        """cmd_disable uses init_system.disable_timer."""
+        from fenris.monitor import cmd_disable
+        from argparse import Namespace
+
+        store_path = tmp_path / "observations.db"
+        init_store(store_path)
+        args = Namespace(now=True, store_path=store_path)
+
+        with patch("fenris.monitor.disable_timer") as mock_disable:
+            cmd_disable(args)
+            mock_disable.assert_called_once_with(True)
+
+    def test_cmd_collect_uses_init_system(self):
+        """cmd_collect uses init_system.collect_now."""
+        from fenris.monitor import cmd_collect
+        from argparse import Namespace
+
+        args = Namespace()
+
+        with patch("fenris.monitor.collect_now") as mock_collect:
+            cmd_collect(args)
+            mock_collect.assert_called_once()
+
+
+# ---------------------------------------------------------------------------
+# Edge cases
+# ---------------------------------------------------------------------------
+
+class TestEdgeCases:
+    """Test edge cases and error handling."""
+
+    def test_systemd_enable_failure_produces_stderr(self):
+        """Systemd enable failure produces error message on stderr."""
+        with patch("fenris.init_system.subprocess") as mock_sub:
+            mock_sub.run.return_value = MagicMock(
+                returncode=1, stderr="Permission denied"
+            )
+            with pytest.raises(SystemExit):
+                _systemd_enable(now=True)
+
+    def test_runit_collect_missing_script(self):
+        """Runit collect exits when fenris-collect script not found."""
+        with patch("fenris.init_system.Path") as mock_path:
+            mock_path.return_value.exists.return_value = False
+            with pytest.raises(SystemExit) as exc_info:
+                _runit_collect()
+            assert exc_info.value.code == 1
+
+    def test_systemd_query_state_timeout(self):
+        """Systemd query state handles subprocess timeout."""
+        with patch("fenris.init_system._systemctl_show") as mock_show:
+            mock_show.return_value = {}
+            result = _systemd_query_state()
+            assert result["boot_enabled"] is False
+            assert result["timer_active"] is False

tests/test_issue_77.py

@@ -0,0 +1,258 @@
+"""Tests for issue #77: Show honest qualifying-day progress and confidence.
+
+These tests verify that:
+1. Warming progress shows detailed qualifying day breakdown
+2. Confidence state accurately reflects qualifying day progress
+3. Edge cases like zero-delta intervals and unknown daily shares are handled
+4. qualifying_days_progress shows honest qualifying day count
+"""
+import sqlite3
+from datetime import datetime, timedelta, timezone
+from pathlib import Path
+
+import pytest
+import sys
+sys.path.insert(0, str(Path(__file__).parent.parent / "src"))
+
+from fenris.store import init_store
+from fenris.monitoring_periods import ensure_period_open, close_period
+from fenris.projection import (
+    compute_projection, ConfidenceState, BaselineTier,
+    WARMING_MIN_DAYS, WARMING_COVERAGE_FLOOR, WARMING_MAX_LOW_COVERAGE,
+)
+
+
+@pytest.fixture
+def store(tmp_path):
+    conn = init_store(tmp_path / "test.db")
+    yield conn
+    conn.close()
+
+
+def _clock(year=2026, month=9, day=30, hour=12):
+    return datetime(year, month, day, hour, 0, 0, tzinfo=timezone.utc)
+
+
+def _insert_baseline(conn, tbw_tb=1.0, verified=True, model="Samsung SSD 970 EVO Plus 1TB"):
+    conn.execute(
+        "INSERT INTO endurance_baseline "
+        "(tbw_terabytes, source_url, document_revision, entry_date, model_string, "
+        " nominal_capacity_bytes, validated_by, verified, created_at, updated_at) "
+        "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)",
+        (tbw_tb, "https://example.com/spec", "v1.0", "2026-01-01", model, 1024000000000,
+         "machine_match" if verified else None, verified, "2026-01-01T00:00:00+00:00",
+         "2026-01-01T00:00:00+00:00"),
+    )
+    conn.commit()
+
+
+def _insert_segment(conn, opened_at="2026-09-01T00:00:00+00:00",
+                     identity_key="nqn.test", degraded=False,
+                     mn="Samsung SSD 970 EVO Plus 1TB"):
+    conn.execute(
+        "INSERT INTO controller_segments "
+        "(opened_at, identity_key, identity_degraded, subnqn, sn, mn, fr, vid, ssvid, transport) "
+        "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)",
+        (opened_at, identity_key, degraded, "nqn.test", "SN123", mn, "FW1", "0x144d", "0x144d", "pcie"),
+    )
+    conn.commit()
+
+
+def _insert_day(conn, day, bw=1024*1024*100, coverage=0.95, samples=24):
+    conn.execute(
+        "INSERT INTO day_aggregates (day, active_seconds, idle_seconds, powered_off_seconds, "
+        "unknown_seconds, bytes_written_delta, bytes_read_delta, sample_count, coverage) "
+        "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)",
+        (day, 3600, 0, 0, 0, bw, 0, samples, coverage),
+    )
+    conn.commit()
+
+
+def _insert_sample(conn, ts, pu=5):
+    conn.execute(
+        "INSERT INTO samples (ts, device, data_units_written, data_units_read, "
+        "percentage_used, bytes_written, bytes_read, power_on_hours) "
+        "VALUES (?, ?, ?, ?, ?, ?, ?, ?)",
+        (ts, "/dev/nvme0n1", 1000000, 500000, pu, 512000000000, 256000000000, 8765),
+    )
+    conn.commit()
+
+
+def _open_period(conn, start="2026-09-01T00:00:00+00:00"):
+    # Convert string to datetime if needed
+    if isinstance(start, str):
+        start = datetime.fromisoformat(start)
+    ensure_period_open(conn, start)
+    conn.commit()
+
+
+class TestHonestQualifyingProgress:
+    """Issue #77: Show honest qualifying-day progress and confidence."""
+
+    def test_warming_shows_qualifying_vs_nonqualifying(self, store):
+        """Warming progress shows both qualifying and non-qualifying days."""
+        _insert_baseline(store, tbw_tb=10.0, verified=True)
+        _insert_segment(store, opened_at="2026-09-20T00:00:00+00:00")
+        _open_period(store, start="2026-09-20T00:00:00+00:00")
+        bw = 100 * 1024 * 1024
+        
+        # 12 qualifying days + 2 non-qualifying (low coverage)
+        for i in range(14):
+            d = (datetime(2026, 9, 20) + timedelta(days=i)).strftime("%Y-%m-%d")
+            cov = 0.30 if i < 2 else 0.95  # First 2 days have low coverage
+            _insert_day(store, d, bw=bw, coverage=cov)
+        
+        _insert_sample(store, "2026-09-30T10:00:00+00:00", pu=5)
+        result = compute_projection(store, _clock())
+        
+        # After warming, qualifying_days_progress shows honest count
+        assert result.warming_fact is None  # Not warming (14 total, 2 below <= WARMING_MAX_LOW_COVERAGE)
+        assert result.qualifying_days_progress is not None
+        assert "12 of 14 qualifying days" in result.qualifying_days_progress
+        assert "2 below coverage" in result.qualifying_days_progress
+        
+    def test_warming_progress_includes_nonqualifying_reason(self, store):
+        """Warming progress indicates why days don't qualify."""
+        _insert_baseline(store, tbw_tb=10.0, verified=True)
+        _insert_segment(store, opened_at="2026-09-20T00:00:00+00:00")
+        _open_period(store, start="2026-09-20T00:00:00+00:00")
+        bw = 100 * 1024 * 1024
+        
+        # 13 qualifying days + 1 non-qualifying (zero samples)
+        for i in range(14):
+            d = (datetime(2026, 9, 20) + timedelta(days=i)).strftime("%Y-%m-%d")
+            samples = 0 if i == 0 else 24  # First day has no samples
+            _insert_day(store, d, bw=bw, samples=samples)
+        
+        _insert_sample(store, "2026-09-30T10:00:00+00:00", pu=5)
+        result = compute_projection(store, _clock())
+        
+        # After warming, qualifying_days_progress shows honest count
+        assert result.warming_fact is None  # Not warming (14 total, 1 below <= WARMING_MAX_LOW_COVERAGE)
+        assert result.qualifying_days_progress is not None
+        assert "13 of 14 qualifying days" in result.qualifying_days_progress
+        assert "1 below coverage" in result.qualifying_days_progress
+        
+    def test_confidence_updates_as_qualifying_days_increase(self, store):
+        """Confidence state reflects actual qualifying day count."""
+        _insert_baseline(store, tbw_tb=10.0, verified=True)
+        _insert_segment(store, opened_at="2026-09-20T00:00:00+00:00")
+        _open_period(store, start="2026-09-20T00:00:00+00:00")
+        bw = 100 * 1024 * 1024
+        
+        # Start with 10 days (below minimum)
+        for i in range(10):
+            d = (datetime(2026, 9, 20) + timedelta(days=i)).strftime("%Y-%m-%d")
+            _insert_day(store, d, bw=bw, coverage=0.95)
+        
+        _insert_sample(store, "2026-09-30T10:00:00+00:00", pu=5)
+        result = compute_projection(store, _clock())
+        
+        # Should be warming
+        assert result.warming_fact is not None
+        assert result.confidence_state == ConfidenceState.LIMITED
+        
+    def test_zero_rate_with_qualifying_days(self, store):
+        """Zero rate with qualifying days shows honest state."""
+        _insert_baseline(store, tbw_tb=10.0, verified=True)
+        _insert_segment(store, opened_at="2026-09-20T00:00:00+00:00")
+        _open_period(store, start="2026-09-20T00:00:00+00:00")
+        
+        # 14 days with zero bytes written
+        for i in range(14):
+            d = (datetime(2026, 9, 20) + timedelta(days=i)).strftime("%Y-%m-%d")
+            _insert_day(store, d, bw=0, coverage=0.95)
+        
+        _insert_sample(store, "2026-09-30T10:00:00+00:00", pu=5)
+        result = compute_projection(store, _clock())
+        
+        # Zero rate should be UNSUPPORTED
+        assert result.confidence_state == ConfidenceState.UNSUPPORTED
+        assert result.zero_rate_fact is not None
+        assert "no finite projection" in result.zero_rate_fact
+        
+    def test_qualifying_days_excludes_low_coverage(self, store):
+        """Days below 50% coverage don't count as qualifying."""
+        _insert_baseline(store, tbw_tb=10.0, verified=True)
+        _insert_segment(store, opened_at="2026-09-20T00:00:00+00:00")
+        _open_period(store, start="2026-09-20T00:00:00+00:00")
+        bw = 100 * 1024 * 1024
+        
+        # 14 days total, but 3 have low coverage
+        for i in range(14):
+            d = (datetime(2026, 9, 20) + timedelta(days=i)).strftime("%Y-%m-%d")
+            cov = 0.30 if i < 3 else 0.95
+            _insert_day(store, d, bw=bw, coverage=cov)
+        
+        _insert_sample(store, "2026-09-30T10:00:00+00:00", pu=5)
+        result = compute_projection(store, _clock())
+        
+        # Should still be warming (3 days below coverage > WARMING_MAX_LOW_COVERAGE=2)
+        assert result.warming_fact is not None
+        assert "warming up" in result.warming_fact.lower()
+        
+    def test_qualifying_days_excludes_zero_samples(self, store):
+        """Days with zero samples don't count as qualifying."""
+        _insert_baseline(store, tbw_tb=10.0, verified=True)
+        _insert_segment(store, opened_at="2026-09-20T00:00:00+00:00")
+        _open_period(store, start="2026-09-20T00:00:00+00:00")
+        bw = 100 * 1024 * 1024
+        
+        # 14 days total, but 3 have zero samples
+        for i in range(14):
+            d = (datetime(2026, 9, 20) + timedelta(days=i)).strftime("%Y-%m-%d")
+            samples = 0 if i < 3 else 24
+            _insert_day(store, d, bw=bw, samples=samples)
+        
+        _insert_sample(store, "2026-09-30T10:00:00+00:00", pu=5)
+        result = compute_projection(store, _clock())
+        
+        # Should still be warming
+        assert result.warming_fact is not None
+        assert "warming up" in result.warming_fact.lower()
+        
+    def test_qualifying_days_progress_after_warming(self, store):
+        """After warming, qualifying_days_progress shows honest count."""
+        _insert_baseline(store, tbw_tb=10.0, verified=True)
+        _insert_segment(store, opened_at="2026-09-17T00:00:00+00:00")
+        _open_period(store, start="2026-09-17T00:00:00+00:00")
+        bw = 100 * 1024 * 1024
+        
+        # 14 total days, 12 qualifying (2 below coverage)
+        for i in range(14):
+            d = (datetime(2026, 9, 17) + timedelta(days=i)).strftime("%Y-%m-%d")
+            cov = 0.30 if i < 2 else 0.95  # First 2 days have low coverage
+            _insert_day(store, d, bw=bw, coverage=cov)
+        
+        _insert_sample(store, "2026-09-30T10:00:00+00:00", pu=5)
+        result = compute_projection(store, _clock())
+        
+        # Should not be warming (14 total, 2 below coverage <= WARMING_MAX_LOW_COVERAGE)
+        assert result.warming_fact is None
+        # But qualifying_days_progress should show the honest count
+        assert result.qualifying_days_progress is not None
+        assert "12 of 14 qualifying days" in result.qualifying_days_progress
+        assert "2 below coverage" in result.qualifying_days_progress
+        
+    def test_qualifying_days_progress_all_qualifying(self, store):
+        """When all days qualify, qualifying_days_progress shows 100%."""
+        _insert_baseline(store, tbw_tb=10.0, verified=True)
+        _insert_segment(store, opened_at="2026-09-17T00:00:00+00:00")
+        _open_period(store, start="2026-09-17T00:00:00+00:00")
+        bw = 100 * 1024 * 1024
+        
+        # 14 days, all qualifying
+        for i in range(14):
+            d = (datetime(2026, 9, 17) + timedelta(days=i)).strftime("%Y-%m-%d")
+            _insert_day(store, d, bw=bw, coverage=0.95)
+        
+        _insert_sample(store, "2026-09-30T10:00:00+00:00", pu=5)
+        result = compute_projection(store, _clock())
+        
+        # Should not be warming
+        assert result.warming_fact is None
+        # qualifying_days_progress should show all qualifying
+        assert result.qualifying_days_progress is not None
+        assert "14 of 14 qualifying days" in result.qualifying_days_progress
+        # Should not show "below coverage" since all qualify
+        assert "below coverage" not in result.qualifying_days_progress

tests/test_issue_79.py

@@ -0,0 +1,318 @@
+"""Tests for issue #79: Apply Fenris identity and Drive health grouping.
+
+Covers:
+- TPH-1: Titlebox shows Fenris identity with wolf fallback
+- TPH-11: Single maker-credit placement, vendor wear under Drive health
+- Preserve: continuity, pause block, quit rail, auth banner
+"""
+import sqlite3
+from datetime import datetime, timedelta, timezone
+from pathlib import Path
+from unittest.mock import patch
+
+import pytest
+import sys
+
+sys.path.insert(0, str(Path(__file__).parent.parent / "src"))
+
+from fenris.store import init_store
+from fenris.monitoring_periods import ensure_period_open
+from fenris.tui import FenrisTuiApp
+
+
+# ---------------------------------------------------------------------------
+# Helpers (reuse from test_tui.py)
+# ---------------------------------------------------------------------------
+
+def _clock(year=2026, month=9, day=30, hour=12):
+    return datetime(year, month, day, hour, 0, 0, tzinfo=timezone.utc)
+
+
+def _insert_baseline(conn, tbw_tb=1.0, verified=True,
+                      model="Samsung SSD 970 EVO Plus 1TB"):
+    conn.execute(
+        "INSERT INTO endurance_baseline "
+        "(tbw_terabytes, source_url, document_revision, entry_date, model_string, "
+        " nominal_capacity_bytes, validated_by, verified, created_at, updated_at) "
+        "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)",
+        (tbw_tb, "https://example.com/spec", "v1.0", "2026-01-01", model,
+         1024000000000, "machine_match" if verified else None, verified,
+         "2026-01-01T00:00:00+00:00", "2026-01-01T00:00:00+00:00"),
+    )
+    conn.commit()
+
+
+def _insert_segment(conn, opened_at="2026-09-01T00:00:00+00:00",
+                     identity_key="nqn.test", degraded=False,
+                     mn="Samsung SSD 970 EVO Plus 1TB"):
+    conn.execute(
+        "INSERT INTO controller_segments "
+        "(opened_at, identity_key, identity_degraded, subnqn, sn, mn, fr, vid, ssvid, transport) "
+        "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)",
+        (opened_at, identity_key, degraded, "nqn.test", "SN123", mn, "FW1",
+         "0x144d", "0x144d", "pcie"),
+    )
+    conn.commit()
+
+
+def _insert_day(conn, day, bw=1024*1024*100, coverage=0.95, samples=24):
+    conn.execute(
+        "INSERT INTO day_aggregates (day, active_seconds, idle_seconds, powered_off_seconds, "
+        "unknown_seconds, bytes_written_delta, bytes_read_delta, sample_count, coverage) "
+        "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)",
+        (day, 3600, 0, 0, 0, bw, 0, samples, coverage),
+    )
+    conn.commit()
+
+
+def _insert_sample(conn, ts, pu=5, device="/dev/nvme0n1"):
+    conn.execute(
+        "INSERT INTO samples (ts, device, data_units_written, data_units_read, "
+        "percentage_used, bytes_written, bytes_read, power_on_hours) "
+        "VALUES (?, ?, ?, ?, ?, ?, ?, ?)",
+        (ts, device, 1000000, 500000, pu, 512000000000, 256000000000, 8765),
+    )
+    conn.commit()
+
+
+def _open_period(conn, start="2026-09-01T00:00:00+00:00"):
+    ensure_period_open(conn, datetime.fromisoformat(start))
+
+
+# ---------------------------------------------------------------------------
+# Issue #79: Fenris identity and Drive health grouping
+# ---------------------------------------------------------------------------
+
+class TestFenrisIdentity:
+    """TPH-1: Titlebox shows Fenris identity with wolf fallback."""
+
+    @pytest.mark.asyncio
+    async def test_titlebox_shows_wolf_identity(self, tmp_path):
+        """Top titlebox reads 🐺 Fenris by Bongbetic."""
+        app = FenrisTuiApp(
+            store_path=tmp_path / "nonexistent.db",
+            refresh_interval_s=0.2,
+        )
+        async with app.run_test(size=(120, 24)) as pilot:
+            headline = str(app.query_one("#headline-band").render())
+            assert "🐺 Fenris by Bongbetic" in headline
+
+    @pytest.mark.asyncio
+    async def test_titlebox_fallback_without_wolf(self, tmp_path):
+        """Fallback to 'Fenris by Bongbetic' when wolf is unsupported."""
+        app = FenrisTuiApp(
+            store_path=tmp_path / "nonexistent.db",
+            refresh_interval_s=0.2,
+        )
+        # Simulate narrow terminal that can't render wolf
+        async with app.run_test(size=(60, 24)) as pilot:
+            headline = str(app.query_one("#headline-band").render())
+            # Either shows wolf or fallback - both are acceptable
+            assert "Fenris by Bongbetic" in headline
+
+    @pytest.mark.asyncio
+    async def test_wolf_never_shows_tofu(self, tmp_path):
+        """Wolf glyph is never rendered as tofu (unsupported character)."""
+        app = FenrisTuiApp(
+            store_path=tmp_path / "nonexistent.db",
+            refresh_interval_s=0.2,
+        )
+        async with app.run_test(size=(120, 24)) as pilot:
+            headline = str(app.query_one("#headline-band").render())
+            # No replacement character (U+FFFD) should appear
+            assert "\ufffd" not in headline.lower()
+            assert "?" not in headline or "Fenris" in headline
+
+    @pytest.mark.asyncio
+    async def test_lifespan_headline_is_data_surface(self, tmp_path):
+        """Lifespan headline remains a data surface, not app title."""
+        conn = init_store(tmp_path / "test.db")
+        _insert_baseline(conn, tbw_tb=1.0, verified=True)
+        _insert_segment(conn)
+        _open_period(conn)
+        for i in range(30):
+            d = (datetime(2026, 9, 1) + timedelta(days=i)).strftime("%Y-%m-%d")
+            _insert_day(conn, d, bw=1024*1024*100, coverage=0.95, samples=24)
+        _insert_sample(conn, "2026-09-30T10:00:00+00:00")
+        conn.close()
+
+        app = FenrisTuiApp(store_path=tmp_path / "test.db")
+        async with app.run_test(size=(120, 24)) as pilot:
+            headline = str(app.query_one("#headline-band").render())
+            # Identity appears once, lifespan is separate data
+            assert "🐺 Fenris by Bongbetic" in headline
+            assert "remaining" in headline.lower() or "projection" in headline.lower()
+
+
+class TestSingleMakerCredit:
+    """TPH-1: Single maker-credit placement in title only."""
+
+    @pytest.mark.asyncio
+    async def test_maker_credit_not_in_service_strip(self, tmp_path):
+        """Remove duplicate maker credit from service facts."""
+        conn = init_store(tmp_path / "test.db")
+        _insert_segment(conn)
+        _open_period(conn)
+        for i in range(20):
+            d = (datetime(2026, 9, 10) + timedelta(days=i)).strftime("%Y-%m-%d")
+            _insert_day(conn, d, bw=1024*1024*100)
+        _insert_sample(conn, "2026-09-30T10:00:00+00:00")
+        conn.close()
+
+        app = FenrisTuiApp(store_path=tmp_path / "test.db")
+        async with app.run_test(size=(120, 24)) as pilot:
+            strip = str(app.query_one("#service-strip").render())
+            # "by Bongbetic" should NOT appear in service strip
+            assert "by Bongbetic" not in strip
+
+    @pytest.mark.asyncio
+    async def test_maker_credit_in_titlebox(self, tmp_path):
+        """Maker credit appears in the titlebox identity."""
+        app = FenrisTuiApp(
+            store_path=tmp_path / "nonexistent.db",
+            refresh_interval_s=0.2,
+        )
+        async with app.run_test(size=(120, 24)) as pilot:
+            headline = str(app.query_one("#headline-band").render())
+            assert "Fenris by Bongbetic" in headline
+
+    @pytest.mark.asyncio
+    async def test_empty_store_no_maker_credit_in_strip(self, tmp_path):
+        """Empty store: no maker credit in service strip."""
+        app = FenrisTuiApp(store_path=tmp_path / "nonexistent.db")
+        async with app.run_test(size=(120, 24)) as pilot:
+            strip = str(app.query_one("#service-strip").render())
+            assert "by Bongbetic" not in strip
+
+    @pytest.mark.asyncio
+    async def test_store_fault_no_maker_credit_in_strip(self, tmp_path):
+        """Store fault: no maker credit in service strip."""
+        # Create a corrupt store
+        db = tmp_path / "test.db"
+        db.write_bytes(b"not a database")
+        app = FenrisTuiApp(store_path=db)
+        async with app.run_test(size=(120, 24)) as pilot:
+            strip = str(app.query_one("#service-strip").render())
+            assert "by Bongbetic" not in strip
+
+
+class TestDriveHealthVendorWear:
+    """TPH-1: Vendor wear renders under Drive health context."""
+
+    @pytest.mark.asyncio
+    async def test_vendor_wear_in_drive_health(self, tmp_path):
+        """Vendor wear shows with health context, not as Settings."""
+        conn = init_store(tmp_path / "test.db")
+        _insert_segment(conn)
+        _open_period(conn)
+        for i in range(20):
+            d = (datetime(2026, 9, 10) + timedelta(days=i)).strftime("%Y-%m-%d")
+            _insert_day(conn, d, bw=1024*1024*100)
+        _insert_sample(conn, "2026-09-30T10:00:00+00:00", pu=10)
+        conn.close()
+
+        app = FenrisTuiApp(store_path=tmp_path / "test.db")
+        async with app.run_test(size=(120, 24)) as pilot:
+            health = str(app.query_one("#drive-health").render())
+            # Vendor wear should be present with health context
+            assert "vendor wear" in health.lower()
+            # Should show thermal, spare, errors, etc.
+            assert "temperature" in health.lower()
+            assert "spare" in health.lower()
+            assert "media errors" in health.lower()
+            # Settings section should NOT be a separate heading
+            assert "[bold]Settings[/bold]" not in health
+
+    @pytest.mark.asyncio
+    async def test_missing_wear_values_honest(self, tmp_path):
+        """Missing values remain honest unavailable facts."""
+        conn = init_store(tmp_path / "test.db")
+        _insert_segment(conn)
+        _open_period(conn)
+        for i in range(20):
+            d = (datetime(2026, 9, 10) + timedelta(days=i)).strftime("%Y-%m-%d")
+            _insert_day(conn, d, bw=1024*1024*100)
+        # Insert sample with zero wear values
+        conn.execute(
+            "INSERT INTO samples (ts, device, data_units_written, data_units_read, "
+            "percentage_used, bytes_written, bytes_read, power_on_hours) "
+            "VALUES (?, ?, ?, ?, ?, ?, ?, ?)",
+            ("2026-09-30T10:00:00+00:00", "/dev/nvme0n1", 0, 0, 0, 0, 0, 0),
+        )
+        conn.commit()
+        conn.close()
+
+        app = FenrisTuiApp(store_path=tmp_path / "test.db")
+        async with app.run_test(size=(120, 24)) as pilot:
+            health = str(app.query_one("#drive-health").render())
+            # Should show 0% used or honest zero, not crash
+            assert "vendor wear" in health.lower()
+
+
+class TestPreservedBehavior:
+    """Preserve existing continuity, pause, quit, auth behavior."""
+
+    @pytest.mark.asyncio
+    async def test_continuity_preserved(self, tmp_path):
+        """Continuity wording preserved in service strip."""
+        conn = init_store(tmp_path / "test.db")
+        _open_period(conn)
+        conn.close()
+        app = FenrisTuiApp(store_path=tmp_path / "test.db")
+
+        with patch("fenris.tui.query_service_state", return_value={
+            "boot_enabled": True, "timer_active": True,
+            "last_collect_ok": True, "last_collect_age_s": 60,
+            "last_collect_reason": None,
+        }):
+            async with app.run_test(size=(120, 24)) as pilot:
+                strip = str(app.query_one("#service-strip").render())
+                assert "continuity" in strip.lower()
+                assert "monitoring" in strip.lower()
+
+    @pytest.mark.asyncio
+    async def test_quit_rail_preserved(self, tmp_path):
+        """Separate q QUIT TUI rail preserved."""
+        app = FenrisTuiApp(store_path=tmp_path / "nonexistent.db")
+        async with app.run_test(size=(120, 24)) as pilot:
+            rail = str(app.query_one("#quit-rail").render())
+            assert "q QUIT TUI" in rail
+
+    @pytest.mark.asyncio
+    async def test_auth_banner_preserved(self, tmp_path):
+        """Polkit authentication banner lifecycle preserved."""
+        app = FenrisTuiApp(
+            store_path=tmp_path / "nonexistent.db",
+            refresh_interval_s=0.2,
+        )
+        async with app.run_test(size=(120, 24)) as pilot:
+            headline = str(app.query_one("#headline-band").render())
+            assert "polkit" in headline.lower()
+            # Should clear after first tick
+            await pilot.pause(0.25)
+            headline_after = str(app.query_one("#headline-band").render())
+            assert "polkit" not in headline_after.lower()
+
+    @pytest.mark.asyncio
+    async def test_deliberate_pause_block_preserved(self, tmp_path):
+        """Deliberate pause banner preserved."""
+        db = tmp_path / "test.db"
+        conn = init_store(db)
+        conn.execute(
+            "INSERT INTO monitoring_periods (started_at, ended_at, end_cause) "
+            "VALUES (?, ?, ?)",
+            ("2026-09-01T09:00:00+00:00", "2026-09-01T10:00:00+00:00", "user_disabled"),
+        )
+        conn.commit()
+        conn.close()
+        app = FenrisTuiApp(store_path=db)
+
+        with patch("fenris.tui.query_service_state", return_value={
+            "boot_enabled": False, "timer_active": False,
+            "last_collect_ok": None, "last_collect_age_s": None,
+            "last_collect_reason": None,
+        }):
+            async with app.run_test(size=(120, 24)) as pilot:
+                banner = str(app.query_one("#paused-banner").render())
+                assert "paused" in banner.lower()
+                assert "deliberate" in banner.lower()

tests/test_issue_80.py

@@ -0,0 +1,482 @@
+"""Integration tests for issue #80: Persist accessible colour and motion preferences.
+
+Covers:
+  - AC80-1: Amber/Nord/High Contrast presets with Amber default
+  - AC80-2: t preset and m motion controls with clickable equivalents
+  - AC80-3: Persistent user-scoped XDG TUI preferences
+  - AC80-4: Reduced motion makes Monitoring steady
+  - AC80-5: Theme roles for graph rendering
+  - AC80-6: Headless interaction tests with temporary user config
+"""
+import json
+import os
+from datetime import datetime, timedelta, timezone
+from pathlib import Path
+from unittest.mock import patch
+
+import pytest
+import sys
+
+sys.path.insert(0, str(Path(__file__).parent.parent / "src"))
+
+from fenris.store import init_store
+from fenris.preferences import (
+    load_preferences,
+    save_preferences,
+    get_preference_path,
+)
+from fenris.themes import get_theme, get_graph_colors, THEME_NAMES
+from fenris.status_composition import (
+    StatusState,
+    compose_status,
+    render_status_tui,
+)
+
+
+# ---------------------------------------------------------------------------
+# Helpers
+# ---------------------------------------------------------------------------
+
+def _clock(year=2026, month=9, day=30, hour=12):
+    return datetime(year, month, day, hour, 0, 0, tzinfo=timezone.utc)
+
+
+def _insert_segment(conn, opened_at="2026-09-01T00:00:00+00:00",
+                     identity_key="nqn.test", degraded=False,
+                     mn="Samsung SSD 970 EVO Plus 1TB"):
+    conn.execute(
+        "INSERT INTO controller_segments "
+        "(opened_at, identity_key, identity_degraded, subnqn, sn, mn, fr, vid, ssvid, transport) "
+        "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)",
+        (opened_at, identity_key, degraded, "nqn.test", "SN123", mn, "FW1",
+         "0x144d", "0x144d", "pcie"),
+    )
+    conn.commit()
+
+
+def _insert_day(conn, day, bw=1024*1024*100, coverage=0.95, samples=24):
+    conn.execute(
+        "INSERT INTO day_aggregates (day, active_seconds, idle_seconds, powered_off_seconds, "
+        "unknown_seconds, bytes_written_delta, bytes_read_delta, sample_count, coverage) "
+        "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)",
+        (day, 3600, 0, 0, 0, bw, 0, samples, coverage),
+    )
+    conn.commit()
+
+
+def _insert_sample(conn, ts, device="/dev/nvme0n1"):
+    conn.execute(
+        "INSERT INTO samples (ts, device, data_units_written, data_units_read, "
+        "percentage_used, bytes_written, bytes_read, power_on_hours) "
+        "VALUES (?, ?, ?, ?, ?, ?, ?, ?)",
+        (ts, device, 1000000, 500000, 5, 512000000000, 256000000000, 8765),
+    )
+    conn.commit()
+
+
+def _open_period(conn, start="2026-09-01T00:00:00+00:00"):
+    from fenris.monitoring_periods import ensure_period_open
+    ensure_period_open(conn, datetime.fromisoformat(start))
+
+
+def _make_prefs_dir(tmp_path: Path) -> Path:
+    config_home = tmp_path / ".config"
+    config_home.mkdir(parents=True, exist_ok=True)
+    return config_home
+
+
+# ---------------------------------------------------------------------------
+# AC80-1: Preset loading and application
+# ---------------------------------------------------------------------------
+
+class TestPresetLoading:
+    """Themes load from preferences and apply to the TUI."""
+
+    @pytest.mark.asyncio
+    async def test_tui_applies_amber_theme_by_default(self, tmp_path):
+        """TUI starts with the Amber theme when no preferences exist."""
+        from fenris.tui import FenrisTuiApp
+
+        config_home = _make_prefs_dir(tmp_path)
+        with patch.dict(os.environ, {"XDG_CONFIG_HOME": str(config_home)}):
+            app = FenrisTuiApp(store_path=tmp_path / "nonexistent.db")
+            async with app.run_test() as pilot:
+                # Theme should be fenris-amber
+                assert app.theme == "fenris-amber"
+
+    @pytest.mark.asyncio
+    async def test_tui_applies_nord_theme_from_prefs(self, tmp_path):
+        """TUI applies Nord theme from saved preferences."""
+        from fenris.tui import FenrisTuiApp
+
+        config_home = _make_prefs_dir(tmp_path)
+        with patch.dict(os.environ, {"XDG_CONFIG_HOME": str(config_home)}):
+            save_preferences(theme="nord", reduced_motion=False)
+            app = FenrisTuiApp(store_path=tmp_path / "nonexistent.db")
+            async with app.run_test() as pilot:
+                assert app.theme == "fenris-nord"
+
+    @pytest.mark.asyncio
+    async def test_tui_applies_high_contrast_from_prefs(self, tmp_path):
+        """TUI applies High Contrast theme from saved preferences."""
+        from fenris.tui import FenrisTuiApp
+
+        config_home = _make_prefs_dir(tmp_path)
+        with patch.dict(os.environ, {"XDG_CONFIG_HOME": str(config_home)}):
+            save_preferences(theme="high_contrast", reduced_motion=False)
+            app = FenrisTuiApp(store_path=tmp_path / "nonexistent.db")
+            async with app.run_test() as pilot:
+                assert app.theme == "fenris-high-contrast"
+
+    @pytest.mark.asyncio
+    async def test_tui_applies_reduced_motion_from_prefs(self, tmp_path):
+        """TUI respects reduced_motion preference."""
+        from fenris.tui import FenrisTuiApp
+        from fenris.status_composition import compose_status
+
+        config_home = _make_prefs_dir(tmp_path)
+        with patch.dict(os.environ, {"XDG_CONFIG_HOME": str(config_home)}):
+            save_preferences(theme="amber", reduced_motion=True)
+            app = FenrisTuiApp(store_path=tmp_path / "nonexistent.db")
+            async with app.run_test() as pilot:
+                # The app should have reduced_motion set
+                assert app._reduced_motion is True
+
+
+# ---------------------------------------------------------------------------
+# AC80-2: t and m key bindings
+# ---------------------------------------------------------------------------
+
+class TestKeyBindings:
+    """t cycles presets and m toggles reduced motion."""
+
+    @pytest.mark.asyncio
+    async def test_t_binding_exists(self, tmp_path):
+        """The TUI has a 't' binding for theme cycling."""
+        from fenris.tui import FenrisTuiApp
+        config_home = _make_prefs_dir(tmp_path)
+        with patch.dict(os.environ, {"XDG_CONFIG_HOME": str(config_home)}):
+            app = FenrisTuiApp(store_path=tmp_path / "nonexistent.db")
+            binding_keys = {b.key for b in app.BINDINGS}
+            assert "t" in binding_keys
+
+    @pytest.mark.asyncio
+    async def test_m_binding_exists(self, tmp_path):
+        """The TUI has an 'm' binding for motion toggle."""
+        from fenris.tui import FenrisTuiApp
+        config_home = _make_prefs_dir(tmp_path)
+        with patch.dict(os.environ, {"XDG_CONFIG_HOME": str(config_home)}):
+            app = FenrisTuiApp(store_path=tmp_path / "nonexistent.db")
+            binding_keys = {b.key for b in app.BINDINGS}
+            assert "m" in binding_keys
+
+    @pytest.mark.asyncio
+    async def test_t_cycles_through_themes(self, tmp_path):
+        """Pressing t cycles through the three presets."""
+        from fenris.tui import FenrisTuiApp
+
+        config_home = _make_prefs_dir(tmp_path)
+        with patch.dict(os.environ, {"XDG_CONFIG_HOME": str(config_home)}):
+            app = FenrisTuiApp(store_path=tmp_path / "nonexistent.db")
+            async with app.run_test() as pilot:
+                # Start at amber
+                assert app.theme == "fenris-amber"
+
+                # Press t to cycle
+                await pilot.press("t")
+                await pilot.pause()
+
+                # Should be nord or high_contrast now
+                assert app.theme in ("fenris-nord", "fenris-high-contrast")
+
+    @pytest.mark.asyncio
+    async def test_m_toggles_reduced_motion(self, tmp_path):
+        """Pressing m toggles reduced motion."""
+        from fenris.tui import FenrisTuiApp
+
+        config_home = _make_prefs_dir(tmp_path)
+        with patch.dict(os.environ, {"XDG_CONFIG_HOME": str(config_home)}):
+            app = FenrisTuiApp(store_path=tmp_path / "nonexistent.db")
+            async with app.run_test() as pilot:
+                # Start with normal motion
+                assert app._reduced_motion is False
+
+                # Press m to toggle
+                await pilot.press("m")
+                await pilot.pause()
+
+                # Should be reduced motion now
+                assert app._reduced_motion is True
+
+                # Press m again to toggle back
+                await pilot.press("m")
+                await pilot.pause()
+
+                assert app._reduced_motion is False
+
+
+# ---------------------------------------------------------------------------
+# AC80-3: Persistence across restart
+# ---------------------------------------------------------------------------
+
+class TestPersistence:
+    """Preferences survive app restart."""
+
+    @pytest.mark.asyncio
+    async def test_theme_survives_restart(self, tmp_path):
+        """Theme preference persists across TUI restart."""
+        from fenris.tui import FenrisTuiApp
+
+        config_home = _make_prefs_dir(tmp_path)
+        with patch.dict(os.environ, {"XDG_CONFIG_HOME": str(config_home)}):
+            # First run: change theme
+            app1 = FenrisTuiApp(store_path=tmp_path / "nonexistent.db")
+            async with app1.run_test() as pilot:
+                await pilot.press("t")
+                await pilot.pause()
+                theme_after_t = app1.theme
+                assert theme_after_t != "fenris-amber"
+
+            # Second run: theme should persist
+            app2 = FenrisTuiApp(store_path=tmp_path / "nonexistent.db")
+            async with app2.run_test() as pilot:
+                assert app2.theme == theme_after_t
+
+    @pytest.mark.asyncio
+    async def test_reduced_motion_survives_restart(self, tmp_path):
+        """Reduced motion preference persists across TUI restart."""
+        from fenris.tui import FenrisTuiApp
+
+        config_home = _make_prefs_dir(tmp_path)
+        with patch.dict(os.environ, {"XDG_CONFIG_HOME": str(config_home)}):
+            # First run: toggle motion
+            app1 = FenrisTuiApp(store_path=tmp_path / "nonexistent.db")
+            async with app1.run_test() as pilot:
+                await pilot.press("m")
+                await pilot.pause()
+                assert app1._reduced_motion is True
+
+            # Second run: motion should persist
+            app2 = FenrisTuiApp(store_path=tmp_path / "nonexistent.db")
+            async with app2.run_test() as pilot:
+                assert app2._reduced_motion is True
+
+
+# ---------------------------------------------------------------------------
+# AC80-4: Reduced motion makes Monitoring steady
+# ---------------------------------------------------------------------------
+
+class TestReducedMotion:
+    """Reduced motion disables the Monitoring dot blink."""
+
+    def test_reduced_motion_disables_blink(self, tmp_path):
+        """compose_status with reduced_motion=True → should_blink=False."""
+        conn = init_store(tmp_path / "test.db")
+        _insert_segment(conn)
+        _open_period(conn)
+        now = _clock()
+        ts = (now - timedelta(minutes=2)).isoformat()
+        _insert_sample(conn, ts)
+        for i in range(20):
+            d = (datetime(2026, 9, 10) + timedelta(days=i)).strftime("%Y-%m-%d")
+            _insert_day(conn, d, bw=1024*1024*100)
+        conn.close()
+
+        conn = init_store(tmp_path / "test.db")
+        svc = {
+            "boot_enabled": True, "timer_active": True,
+            "last_collect_ok": True, "last_collect_age_s": 120,
+            "last_collect_reason": None,
+        }
+        comp = compose_status(conn, svc, now, store_fault=None, newer_schema=None,
+                              reduced_motion=True)
+        assert comp.state == StatusState.MONITORING
+        assert comp.should_blink is False
+        conn.close()
+
+    def test_normal_motion_allows_blink(self, tmp_path):
+        """compose_status with reduced_motion=False → should_blink=True for Monitoring."""
+        conn = init_store(tmp_path / "test.db")
+        _insert_segment(conn)
+        _open_period(conn)
+        now = _clock()
+        ts = (now - timedelta(minutes=2)).isoformat()
+        _insert_sample(conn, ts)
+        for i in range(20):
+            d = (datetime(2026, 9, 10) + timedelta(days=i)).strftime("%Y-%m-%d")
+            _insert_day(conn, d, bw=1024*1024*100)
+        conn.close()
+
+        conn = init_store(tmp_path / "test.db")
+        svc = {
+            "boot_enabled": True, "timer_active": True,
+            "last_collect_ok": True, "last_collect_age_s": 120,
+            "last_collect_reason": None,
+        }
+        comp = compose_status(conn, svc, now, store_fault=None, newer_schema=None,
+                              reduced_motion=False)
+        assert comp.state == StatusState.MONITORING
+        assert comp.should_blink is True
+        conn.close()
+
+    @pytest.mark.asyncio
+    async def test_framework_reduced_motion_honoured(self, tmp_path):
+        """TUI honours Textual's reduced_motion signal."""
+        from fenris.tui import FenrisTuiApp
+
+        config_home = _make_prefs_dir(tmp_path)
+        with patch.dict(os.environ, {"XDG_CONFIG_HOME": str(config_home)}):
+            app = FenrisTuiApp(store_path=tmp_path / "nonexistent.db")
+            async with app.run_test() as pilot:
+                # The app should check for reduced motion on mount
+                assert hasattr(app, '_reduced_motion')
+
+
+# ---------------------------------------------------------------------------
+# AC80-5: Theme roles for graph rendering
+# ---------------------------------------------------------------------------
+
+class TestGraphThemeRoles:
+    """Graph uses theme-derived colours for each bar role."""
+
+    def test_graph_colors_available_for_all_themes(self):
+        """Every theme provides all required graph colour roles."""
+        required_roles = {"allocated", "unallocated", "gap", "zero", "partial"}
+        for name in THEME_NAMES:
+            colors = get_graph_colors(name)
+            assert required_roles.issubset(set(colors.keys())),                 "Theme %s missing roles: %s" % (name, required_roles - set(colors.keys()))
+
+    def test_graph_colors_are_strings(self):
+        """All graph colour values are strings (Textual CSS colour values)."""
+        for name in THEME_NAMES:
+            colors = get_graph_colors(name)
+            for role, color in colors.items():
+                assert isinstance(color, str),                     "Theme %s role %s has non-string color: %s" % (name, role, color)
+
+
+# ---------------------------------------------------------------------------
+# AC80-6: Safe persistence — failure modes
+# ---------------------------------------------------------------------------
+
+class TestSafePersistence:
+    """Preference failures never crash the dashboard."""
+
+    @pytest.mark.asyncio
+    async def test_corrupt_prefs_does_not_crash_tui(self, tmp_path):
+        """Corrupt preference file does not prevent TUI from starting."""
+        from fenris.tui import FenrisTuiApp
+
+        config_home = _make_prefs_dir(tmp_path)
+        fenris_dir = config_home / "fenris"
+        fenris_dir.mkdir(parents=True, exist_ok=True)
+        (fenris_dir / "preferences.json").write_text("{bad json!!!")
+
+        with patch.dict(os.environ, {"XDG_CONFIG_HOME": str(config_home)}):
+            app = FenrisTuiApp(store_path=tmp_path / "nonexistent.db")
+            async with app.run_test() as pilot:
+                # TUI should start with default theme
+                assert app.theme == "fenris-amber"
+                # Dashboard should be functional
+                headline = str(app.query_one("#headline-band").render())
+                assert headline is not None
+
+    @pytest.mark.asyncio
+    async def test_readonly_config_dir_does_not_crash(self, tmp_path):
+        """Read-only config directory does not prevent TUI from starting."""
+        from fenris.tui import FenrisTuiApp
+
+        config_home = _make_prefs_dir(tmp_path)
+        fenris_dir = config_home / "fenris"
+        fenris_dir.mkdir(parents=True, exist_ok=True)
+        fenris_dir.chmod(0o555)
+
+        with patch.dict(os.environ, {"XDG_CONFIG_HOME": str(config_home)}):
+            app = FenrisTuiApp(store_path=tmp_path / "nonexistent.db")
+            async with app.run_test() as pilot:
+                # TUI should start without crash
+                assert app.theme in ("fenris-amber", "fenris-nord", "fenris-high-contrast")
+
+
+# ---------------------------------------------------------------------------
+# CLI isolation (preferences do not affect CLI)
+# ---------------------------------------------------------------------------
+
+class TestCLIIsolation:
+    """Preferences are TUI-only — CLI status is independent."""
+
+    def test_cli_status_unchanged_by_theme(self, tmp_path):
+        """fenris status output does not change based on theme preference."""
+        from fenris.status import get_status
+
+        conn = init_store(tmp_path / "test.db")
+        _insert_segment(conn)
+        _open_period(conn)
+        now = _clock()
+        ts = (now - timedelta(minutes=2)).isoformat()
+        _insert_sample(conn, ts)
+        for i in range(20):
+            d = (datetime(2026, 9, 10) + timedelta(days=i)).strftime("%Y-%m-%d")
+            _insert_day(conn, d, bw=1024*1024*100)
+        conn.close()
+
+        config_home = _make_prefs_dir(tmp_path)
+
+        # With amber theme
+        with patch.dict(os.environ, {"XDG_CONFIG_HOME": str(config_home)}):
+            save_preferences(theme="amber", reduced_motion=False)
+            status_amber = get_status(
+                store_path=tmp_path / "test.db",
+                clock_now=now,
+                query_services=False,
+                query_journal=False,
+            )
+
+        # With high contrast theme
+        with patch.dict(os.environ, {"XDG_CONFIG_HOME": str(config_home)}):
+            save_preferences(theme="high_contrast", reduced_motion=True)
+            status_hc = get_status(
+                store_path=tmp_path / "test.db",
+                clock_now=now,
+                query_services=False,
+                query_journal=False,
+            )
+
+        # Status output should be identical
+        assert status_amber == status_hc
+
+    def test_cli_status_unchanged_by_motion(self, tmp_path):
+        """fenris status output does not change based on reduced_motion preference."""
+        from fenris.status import get_status
+
+        conn = init_store(tmp_path / "test.db")
+        _insert_segment(conn)
+        _open_period(conn)
+        now = _clock()
+        ts = (now - timedelta(minutes=2)).isoformat()
+        _insert_sample(conn, ts)
+        for i in range(20):
+            d = (datetime(2026, 9, 10) + timedelta(days=i)).strftime("%Y-%m-%d")
+            _insert_day(conn, d, bw=1024*1024*100)
+        conn.close()
+
+        config_home = _make_prefs_dir(tmp_path)
+
+        with patch.dict(os.environ, {"XDG_CONFIG_HOME": str(config_home)}):
+            save_preferences(theme="amber", reduced_motion=False)
+            status_normal = get_status(
+                store_path=tmp_path / "test.db",
+                clock_now=now,
+                query_services=False,
+                query_journal=False,
+            )
+
+        with patch.dict(os.environ, {"XDG_CONFIG_HOME": str(config_home)}):
+            save_preferences(theme="amber", reduced_motion=True)
+            status_reduced = get_status(
+                store_path=tmp_path / "test.db",
+                clock_now=now,
+                query_services=False,
+                query_journal=False,
+            )
+
+        assert status_normal == status_reduced

tests/test_legacy_migration.py

@@ -0,0 +1,404 @@
+"""Legacy migration tests.
+
+Tests the idempotent, interruption-safe import of history.jsonl into the
+observation store.
+"""
+import json
+import os
+import sqlite3
+import tempfile
+from datetime import datetime, timezone
+from pathlib import Path
+from typing import Any, Dict
+
+import pytest
+
+# Add src to path for imports
+import sys
+sys.path.insert(0, str(Path(__file__).parent.parent / "src"))
+
+from fenris.legacy import import_legacy_history, is_legacy_imported, _parse_history_line
+from fenris.store import init_store
+
+
+# Fixtures
+
+@pytest.fixture
+def history_fixture() -> str:
+    """Minimal history.jsonl content with two samples."""
+    samples = [
+        {
+            "timestamp": "2026-08-30T10:00:00Z",
+            "device": "/dev/nvme0",
+            "model": "Samsung SSD 970 EVO Plus 1TB",
+            "serial": "S4EWNX0N123456",
+            "firmware_version": "2B2QEXM7",
+            "capacity_bytes": 1024000000000,
+            "data_units_written": 1000000,
+            "data_units_read": 500000,
+            "percentage_used": 5,
+            "power_on_hours": 8765,
+            "temperature": 35,
+            "available_spare": 100,
+            "media_errors": 0,
+            "power_cycles": 1234,
+            "unsafe_shutdowns": 5,
+            "critical_warning": 0,
+        },
+        {
+            "timestamp": "2026-08-30T11:00:00Z",
+            "device": "/dev/nvme0",
+            "model": "Samsung SSD 970 EVO Plus 1TB",
+            "serial": "S4EWNX0N123456",
+            "firmware_version": "2B2QEXM7",
+            "capacity_bytes": 1024000000000,
+            "data_units_written": 1001000,
+            "data_units_read": 501000,
+            "percentage_used": 5,
+            "power_on_hours": 8766,
+            "temperature": 36,
+            "available_spare": 100,
+            "media_errors": 0,
+            "power_cycles": 1234,
+            "unsafe_shutdowns": 5,
+            "critical_warning": 0,
+        },
+    ]
+    return "\n".join(json.dumps(s) for s in samples)
+
+
+@pytest.fixture
+def hourly_fixture() -> str:
+    """Minimal hourly.jsonl content for diffing."""
+    hours = [
+        {
+            "hour": "2026-08-30T10:00:00Z",
+            "bytes_written_delta": 512000000,
+            "bytes_read_delta": 256000000,
+            "sample_count": 1,
+        },
+        {
+            "hour": "2026-08-30T11:00:00Z",
+            "bytes_written_delta": 513000000,
+            "bytes_read_delta": 257000000,
+            "sample_count": 1,
+        },
+    ]
+    return "\n".join(json.dumps(h) for h in hours)
+
+
+@pytest.fixture
+def config_fixture(tmp_path: Path) -> Dict[str, Any]:
+    """Configuration fixture."""
+    return {
+        "device": "/dev/nvme0",
+        "store_path": str(tmp_path / "observations.db"),
+        "data_dir": str(tmp_path),
+    }
+
+
+@pytest.fixture
+def clock_fixture():
+    """Injected clock returning fixed time."""
+    class FakeClock:
+        def __init__(self):
+            self.now = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        
+        def utcnow(self):
+            return self.now
+    
+    return FakeClock()
+
+
+# Test: Idempotency - second run no-ops
+
+def test_import_idempotent(
+    history_fixture: str,
+    config_fixture: Dict[str, Any],
+    clock_fixture,
+):
+    """Given a store with legacy import marker,
+    when import is called again,
+    then it no-ops."""
+    # Create history file
+    history_path = Path(config_fixture["data_dir"]) / "history.jsonl"
+    history_path.write_text(history_fixture)
+    
+    # Initialize store
+    store_path = Path(config_fixture["store_path"])
+    conn = init_store(store_path)
+    
+    # First import
+    result1 = import_legacy_history(conn, history_path, clock=clock_fixture)
+    assert result1["ok"] is True
+    assert result1["skipped"] is False
+    
+    # Second import (should no-op)
+    history_path2 = Path(config_fixture["data_dir"]) / "history.jsonl"
+    history_path2.write_text(history_fixture)
+    result2 = import_legacy_history(conn, history_path2, clock=clock_fixture)
+    assert result2["ok"] is True
+    assert result2["skipped"] is True
+    
+    conn.close()
+
+
+# Test: Interruption safety - single transaction
+
+def test_import_single_transaction(
+    history_fixture: str,
+    config_fixture: Dict[str, Any],
+    clock_fixture,
+):
+    """Given history.jsonl,
+    when import runs,
+    then the entire import is a single transaction."""
+    # Create history file
+    history_path = Path(config_fixture["data_dir"]) / "history.jsonl"
+    history_path.write_text(history_fixture)
+    
+    # Initialize store
+    store_path = Path(config_fixture["store_path"])
+    conn = init_store(store_path)
+    
+    # Import
+    result = import_legacy_history(conn, history_path, clock=clock_fixture)
+    assert result["ok"] is True
+    
+    # Verify all data was imported atomically
+    cursor = conn.execute("SELECT COUNT(*) FROM samples")
+    assert cursor.fetchone()[0] == 2
+    
+    cursor = conn.execute("SELECT COUNT(*) FROM hour_observations")
+    assert cursor.fetchone()[0] == 2
+    
+    cursor = conn.execute("SELECT COUNT(*) FROM monitoring_periods")
+    assert cursor.fetchone()[0] == 1
+    
+    conn.close()
+
+
+# Test: Legacy files renamed to *.migrated after commit
+
+def test_legacy_files_renamed(
+    history_fixture: str,
+    config_fixture: Dict[str, Any],
+    clock_fixture,
+):
+    """Given history.jsonl and hourly.jsonl,
+    when import commits,
+    then files are renamed to *.migrated."""
+    # Create files
+    history_path = Path(config_fixture["data_dir"]) / "history.jsonl"
+    history_path.write_text(history_fixture)
+    
+    hourly_path = Path(config_fixture["data_dir"]) / "hourly.jsonl"
+    hourly_path.write_text("{}")
+    
+    # Initialize store
+    store_path = Path(config_fixture["store_path"])
+    conn = init_store(store_path)
+    
+    # Import
+    result = import_legacy_history(conn, history_path, hourly_path=hourly_path, clock=clock_fixture)
+    assert result["ok"] is True
+    
+    # Verify files renamed
+    assert not history_path.exists()
+    assert history_path.with_suffix(history_path.suffix + ".migrated").exists()
+    
+    assert not hourly_path.exists()
+    assert hourly_path.with_suffix(hourly_path.suffix + ".migrated").exists()
+    
+    conn.close()
+
+
+# Test: Malformed lines quarantined with logged count
+
+def test_malformed_lines_quarantined(
+    config_fixture: Dict[str, Any],
+    clock_fixture,
+):
+    """Given history.jsonl with malformed lines,
+    when import runs,
+    then malformed lines are quarantined with logged count."""
+    # Create history with malformed lines
+    history_content = "\n".join([
+        '{"timestamp": "2026-08-30T10:00:00Z", "model": "Test", "serial": "123", "firmware_version": "1.0", "data_units_written": 1000, "data_units_read": 500, "percentage_used": 5, "power_on_hours": 100, "temperature": 35}',
+        'NOT JSON',
+        '{"timestamp": "2026-08-30T11:00:00Z", "model": "Test", "serial": "123", "firmware_version": "1.0", "data_units_written": 1001, "data_units_read": 501, "percentage_used": 5, "power_on_hours": 101, "temperature": 36}',
+    ])
+    history_path = Path(config_fixture["data_dir"]) / "history.jsonl"
+    history_path.write_text(history_content)
+    
+    # Initialize store
+    store_path = Path(config_fixture["store_path"])
+    conn = init_store(store_path)
+    
+    # Import
+    result = import_legacy_history(conn, history_path, clock=clock_fixture)
+    assert result["ok"] is True
+    assert result["malformed_lines"] == 1
+    assert result["samples_imported"] == 2
+    
+    conn.close()
+
+
+# Test: hourly.jsonl diffed and logged but never trusted
+
+def test_hourly_jsonl_diffed(
+    history_fixture: str,
+    hourly_fixture: str,
+    config_fixture: Dict[str, Any],
+    clock_fixture,
+):
+    """Given history.jsonl and hourly.jsonl with mismatches,
+    when import runs,
+    then mismatches are diffed and logged."""
+    # Create files
+    history_path = Path(config_fixture["data_dir"]) / "history.jsonl"
+    history_path.write_text(history_fixture)
+    
+    hourly_path = Path(config_fixture["data_dir"]) / "hourly.jsonl"
+    hourly_path.write_text(hourly_fixture)
+    
+    # Initialize store
+    store_path = Path(config_fixture["store_path"])
+    conn = init_store(store_path)
+    
+    # Import (should not fail even with mismatches)
+    result = import_legacy_history(conn, history_path, hourly_path=hourly_path, clock=clock_fixture)
+    assert result["ok"] is True
+    
+    # Verify data was imported from history.jsonl, not hourly.jsonl
+    cursor = conn.execute("SELECT bytes_written_delta FROM hour_observations ORDER BY hour")
+    deltas = [row[0] for row in cursor.fetchall()]
+    
+    # Should match history.jsonl derived values, not hourly.jsonl
+    assert len(deltas) == 2
+    
+    conn.close()
+
+
+# Test: Legacy identity is mn-only
+
+def test_legacy_identity_mn_only(
+    history_fixture: str,
+    config_fixture: Dict[str, Any],
+    clock_fixture,
+):
+    """Given history.jsonl,
+    when import runs,
+    then legacy segment has mn-only identity."""
+    # Create history file
+    history_path = Path(config_fixture["data_dir"]) / "history.jsonl"
+    history_path.write_text(history_fixture)
+    
+    # Initialize store
+    store_path = Path(config_fixture["store_path"])
+    conn = init_store(store_path)
+    
+    # Import
+    result = import_legacy_history(conn, history_path, clock=clock_fixture)
+    assert result["ok"] is True
+    assert result["legacy_identity_key"] == "legacy|Samsung SSD 970 EVO Plus 1TB"
+    
+    # Verify segment has mn-only identity
+    cursor = conn.execute("SELECT identity_key, mn, sn, subnqn FROM controller_segments")
+    row = cursor.fetchone()
+    assert row[0] == "legacy|Samsung SSD 970 EVO Plus 1TB"
+    assert row[1] == "Samsung SSD 970 EVO Plus 1TB"
+    assert row[2] is None  # sn is None for legacy
+    assert row[3] is None  # subnqn is None for legacy
+    
+    conn.close()
+
+
+# Test: No synthetic baseline created
+
+def test_no_synthetic_baseline(
+    history_fixture: str,
+    config_fixture: Dict[str, Any],
+    clock_fixture,
+):
+    """Given history.jsonl,
+    when import runs,
+    then no endurance baseline is created."""
+    # Create history file
+    history_path = Path(config_fixture["data_dir"]) / "history.jsonl"
+    history_path.write_text(history_fixture)
+    
+    # Initialize store
+    store_path = Path(config_fixture["store_path"])
+    conn = init_store(store_path)
+    
+    # Import
+    result = import_legacy_history(conn, history_path, clock=clock_fixture)
+    assert result["ok"] is True
+    
+    # Verify no baseline created
+    cursor = conn.execute("SELECT COUNT(*) FROM endurance_baseline")
+    assert cursor.fetchone()[0] == 0
+    
+    conn.close()
+
+
+# Test: Monitoring period opened and closed
+
+def test_monitoring_period_opened_closed(
+    history_fixture: str,
+    config_fixture: Dict[str, Any],
+    clock_fixture,
+):
+    """Given history.jsonl,
+    when import runs,
+    then one monitoring period is opened at first sample and closed at migration."""
+    # Create history file
+    history_path = Path(config_fixture["data_dir"]) / "history.jsonl"
+    history_path.write_text(history_fixture)
+    
+    # Initialize store
+    store_path = Path(config_fixture["store_path"])
+    conn = init_store(store_path)
+    
+    # Import
+    result = import_legacy_history(conn, history_path, clock=clock_fixture)
+    assert result["ok"] is True
+    
+    # Verify monitoring period
+    cursor = conn.execute("SELECT started_at, ended_at, end_cause FROM monitoring_periods")
+    row = cursor.fetchone()
+    assert row[0] == "2026-08-30T10:00:00+00:00"  # First sample time
+    assert row[1] == clock_fixture.now.isoformat()  # Migration time
+    assert row[2] == "migrated"
+    
+    conn.close()
+
+
+# Test: Parse history line
+
+def test_parse_history_line_valid():
+    """Given a valid history line,
+    when parsed,
+    then returns the record."""
+    line = '{"timestamp": "2026-08-30T10:00:00Z", "model": "Test", "serial": "123", "firmware_version": "1.0", "data_units_written": 1000, "data_units_read": 500, "percentage_used": 5, "power_on_hours": 100, "temperature": 35}'
+    result = _parse_history_line(line, 1)
+    assert result is not None
+    assert result["model"] == "Test"
+
+
+def test_parse_history_line_malformed():
+    """Given a malformed JSON line,
+    when parsed,
+    then returns None."""
+    result = _parse_history_line("NOT JSON", 1)
+    assert result is None
+
+
+def test_parse_history_line_missing_field():
+    """Given a line with missing required field,
+    when parsed,
+    then returns None."""
+    line = '{"timestamp": "2026-08-30T10:00:00Z", "model": "Test"}'
+    result = _parse_history_line(line, 1)
+    assert result is None

tests/test_monitor.py

@@ -0,0 +1,310 @@
+"""Tests for fenris-monitor helper.
+
+Spec: §8.4, §8.5, §8.6, §8.7
+"""
+import json
+import sqlite3
+from datetime import datetime, timezone
+from pathlib import Path
+from unittest.mock import patch, MagicMock
+
+import pytest
+
+import sys
+sys.path.insert(0, str(Path(__file__).parent.parent / "src"))
+
+from fenris.monitor import (
+    cmd_enable,
+    cmd_disable,
+    cmd_collect,
+    cmd_baseline_set,
+    cmd_baseline_clear,
+    is_root,
+)
+from fenris.store import init_store
+
+
+@pytest.fixture
+def tmp_store(tmp_path):
+    """Create a temporary observation store."""
+    store_path = tmp_path / "observations.db"
+    conn = init_store(store_path)
+    yield conn
+    conn.close()
+
+
+@pytest.fixture
+def store_path(tmp_path):
+    """Return path to a temporary observation store."""
+    return tmp_path / "observations.db"
+
+
+class TestIsRoot:
+    def test_root_returns_true(self):
+        with patch("os.geteuid", return_value=0):
+            assert is_root() is True
+
+    def test_non_root_returns_false(self):
+        with patch("os.geteuid", return_value=1000):
+            assert is_root() is False
+
+
+class TestEnableIdempotentMatrix:
+    """§8.6: Period-row idempotent matrix."""
+
+    def test_first_enable_creates_missing_store(self, store_path):
+        """A fresh package install has a store directory but no database yet."""
+        args = MagicMock(now=False, store_path=store_path)
+
+        with patch("fenris.monitor.enable_timer") as mock_enable:
+            cmd_enable(args)
+
+        conn = init_store(store_path)
+        row = conn.execute(
+            "SELECT ended_at FROM monitoring_periods WHERE ended_at IS NULL"
+        ).fetchone()
+        conn.close()
+        assert row is not None
+
+    def test_first_opens_period(self, store_path):
+        """First-ever enable opens a period at the enable moment."""
+        # Initialize store
+        init_store(store_path)
+        
+        args = MagicMock(now=False, store_path=store_path)
+
+        with patch("fenris.monitor.enable_timer") as mock_enable:
+            cmd_enable(args)
+
+        # Period should be open
+        conn = init_store(store_path)
+        cursor = conn.execute(
+            "SELECT ended_at FROM monitoring_periods WHERE ended_at IS NULL"
+        )
+        assert cursor.fetchone() is not None
+        conn.close()
+
+    def test_resume_with_open_period_noop(self, store_path):
+        """Resume with open period: no-op (gap stays inside as unknown)."""
+        # Initialize store and open a period
+        conn = init_store(store_path)
+        now = datetime.now(timezone.utc)
+        conn.execute(
+            "INSERT INTO monitoring_periods (started_at) VALUES (?)",
+            (now.isoformat(),),
+        )
+        conn.commit()
+        conn.close()
+
+        args = MagicMock(now=True, store_path=store_path)
+
+        with patch("fenris.monitor.enable_timer") as mock_enable:
+            cmd_enable(args)
+
+        # Should still have exactly one open period
+        conn = init_store(store_path)
+        cursor = conn.execute(
+            "SELECT COUNT(*) FROM monitoring_periods WHERE ended_at IS NULL"
+        )
+        assert cursor.fetchone()[0] == 1
+        conn.close()
+
+    def test_resume_with_no_period_opens_new(self, store_path):
+        """Resume with no open period opens a new row."""
+        # Initialize store and close any existing period
+        conn = init_store(store_path)
+        conn.execute(
+            "UPDATE monitoring_periods SET ended_at = ?, end_cause = ?",
+            (datetime.now(timezone.utc).isoformat(), "user_disabled"),
+        )
+        conn.commit()
+        conn.close()
+
+        args = MagicMock(now=True, store_path=store_path)
+
+        with patch("fenris.monitor.enable_timer") as mock_enable:
+            cmd_enable(args)
+
+        # Should have a new open period
+        conn = init_store(store_path)
+        cursor = conn.execute(
+            "SELECT COUNT(*) FROM monitoring_periods WHERE ended_at IS NULL"
+        )
+        assert cursor.fetchone()[0] == 1
+        conn.close()
+
+
+class TestDisableIdempotentMatrix:
+    """§8.6: Period-row idempotent matrix."""
+
+    def test_pause_with_open_period_closes_user_disabled(self, store_path):
+        """Pause with open period closes it user_disabled."""
+        # Initialize store and open a period
+        conn = init_store(store_path)
+        now = datetime.now(timezone.utc)
+        conn.execute(
+            "INSERT INTO monitoring_periods (started_at) VALUES (?)",
+            (now.isoformat(),),
+        )
+        conn.commit()
+        conn.close()
+
+        args = MagicMock(now=True, store_path=store_path)
+
+        with patch("fenris.monitor.disable_timer") as mock_disable:
+            cmd_disable(args)
+
+        # Period should be closed with user_disabled
+        conn = init_store(store_path)
+        cursor = conn.execute(
+            "SELECT end_cause FROM monitoring_periods WHERE ended_at IS NOT NULL"
+        )
+        assert cursor.fetchone()[0] == "user_disabled"
+        conn.close()
+
+    def test_pause_without_open_period_noop(self, store_path):
+        """Pause otherwise no-ops."""
+        # Initialize store
+        init_store(store_path)
+
+        args = MagicMock(now=True, store_path=store_path)
+
+        with patch("fenris.monitor.disable_timer") as mock_disable:
+            cmd_disable(args)
+
+        # No periods should exist
+        conn = init_store(store_path)
+        cursor = conn.execute("SELECT COUNT(*) FROM monitoring_periods")
+        assert cursor.fetchone()[0] == 0
+        conn.close()
+
+    def test_raw_systemctl_stop_never_records_user_disabled(self, store_path):
+        """Raw systemctl stop outside helper never records user_disabled."""
+        # Initialize store and open a period
+        conn = init_store(store_path)
+        now = datetime.now(timezone.utc)
+        conn.execute(
+            "INSERT INTO monitoring_periods (started_at) VALUES (?)",
+            (now.isoformat(),),
+        )
+        conn.commit()
+
+        # Simulate raw systemctl stop (no monitor involved)
+        # The period stays open - only the sanctioned path closes it
+        cursor = conn.execute(
+            "SELECT end_cause FROM monitoring_periods WHERE ended_at IS NULL"
+        )
+        assert cursor.fetchone() is not None  # Still open
+        conn.close()
+
+
+class TestCollectTrigger:
+    """§8.7: On-demand collection via helper path."""
+
+    def test_collect_triggers_init_system(self):
+        """Collect triggers init_system.collect_now."""
+        args = MagicMock()
+
+        with patch("fenris.monitor.collect_now") as mock_collect:
+            cmd_collect(args)
+            mock_collect.assert_called_once()
+
+    def test_collect_failure_exits_nonzero(self):
+        """Collect failure exits with nonzero status."""
+        args = MagicMock()
+
+        with patch("fenris.monitor.collect_now", side_effect=SystemExit(1)):
+            with pytest.raises(SystemExit) as exc_info:
+                cmd_collect(args)
+            assert exc_info.value.code == 1
+
+
+class TestBaselinePersistence:
+    """PR-14: Baseline persistence behind polkit-guarded helper."""
+
+    def test_baseline_set_persists(self, store_path):
+        """baseline set persists the baseline row."""
+        # Initialize store
+        init_store(store_path)
+
+        args = MagicMock(
+            store_path=store_path,
+            baseline_json=json.dumps(
+                {
+                    "tbw_terabytes": 600,
+                    "source_url": "https://example.com/spec",
+                    "document_revision": "rev1",
+                    "entry_date": "2024-01-01",
+                    "model_string": "Samsung 990 Pro",
+                    "nominal_capacity_bytes": 2000000000000,
+                }
+            )
+        )
+
+        cmd_baseline_set(args)
+
+        conn = init_store(store_path)
+        cursor = conn.execute("SELECT * FROM endurance_baseline")
+        row = cursor.fetchone()
+        assert row is not None
+        assert row[1] == 600.0  # tbw_terabytes
+        conn.close()
+
+    def test_baseline_set_replaces_existing(self, store_path):
+        """baseline set replaces any existing baseline."""
+        # Initialize store and insert initial baseline
+        conn = init_store(store_path)
+        now = datetime.now(timezone.utc)
+        conn.execute(
+            "INSERT INTO endurance_baseline (tbw_terabytes, source_url, "
+            "document_revision, entry_date, model_string, nominal_capacity_bytes, "
+            "created_at, updated_at) VALUES (?, ?, ?, ?, ?, ?, ?, ?)",
+            (400, "old", "v1", "2023-01-01", "Old Model", 1000000000000,
+             now.isoformat(), now.isoformat()),
+        )
+        conn.commit()
+        conn.close()
+
+        args = MagicMock(
+            store_path=store_path,
+            baseline_json=json.dumps(
+                {
+                    "tbw_terabytes": 600,
+                    "source_url": "new",
+                    "document_revision": "v2",
+                    "entry_date": "2024-01-01",
+                    "model_string": "New Model",
+                    "nominal_capacity_bytes": 2000000000000,
+                }
+            )
+        )
+
+        cmd_baseline_set(args)
+
+        conn = init_store(store_path)
+        cursor = conn.execute("SELECT COUNT(*) FROM endurance_baseline")
+        assert cursor.fetchone()[0] == 1  # Only one row
+        conn.close()
+
+    def test_baseline_clear_removes(self, store_path):
+        """baseline clear removes the baseline."""
+        # Initialize store and insert baseline
+        conn = init_store(store_path)
+        now = datetime.now(timezone.utc)
+        conn.execute(
+            "INSERT INTO endurance_baseline (tbw_terabytes, source_url, "
+            "document_revision, entry_date, model_string, nominal_capacity_bytes, "
+            "created_at, updated_at) VALUES (?, ?, ?, ?, ?, ?, ?, ?)",
+            (400, "src", "v1", "2024-01-01", "Model", 1000000000000,
+             now.isoformat(), now.isoformat()),
+        )
+        conn.commit()
+        conn.close()
+
+        args = MagicMock(store_path=store_path)
+        cmd_baseline_clear(args)
+
+        conn = init_store(store_path)
+        cursor = conn.execute("SELECT COUNT(*) FROM endurance_baseline")
+        assert cursor.fetchone()[0] == 0
+        conn.close()

tests/test_monitoring_periods.py

@@ -0,0 +1,147 @@
+"""Monitoring period tests.
+
+From spec §5.2, §8.6, §9.8:
+- Run finding no open period opens one at the run moment, never backdated
+- Wall-clock outside periods excluded from numerator/denominator
+- Powered-off time stays inside a period; disabled time does not
+- End causes: user_disabled, migrated, unknown_gap
+"""
+import sqlite3
+import sys
+from datetime import datetime, timezone, timedelta
+from pathlib import Path
+
+import pytest
+
+sys.path.insert(0, str(Path(__file__).parent.parent / "src"))
+
+from fenris.store import init_store
+from fenris.monitoring_periods import (
+    ensure_period_open,
+    close_period,
+    get_open_period,
+    is_inside_period,
+)
+
+
+@pytest.fixture
+def store_conn(tmp_path: Path):
+    """Initialize an observation store and return a connection."""
+    db_path = tmp_path / "test.db"
+    conn = init_store(db_path)
+    yield conn
+    conn.close()
+
+
+class TestEnsurePeriodOpen:
+    """Spec §9.8: Run finding no open period opens one at the run moment."""
+
+    def test_opens_period_when_none_exists(self, store_conn):
+        """First collection run opens a period at the run moment."""
+        run_time = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        ensure_period_open(store_conn, run_time)
+
+        period = get_open_period(store_conn)
+        assert period is not None
+        assert period["started_at"] == "2026-09-01T12:00:00+00:00"
+        assert period["ended_at"] is None
+        assert period["end_cause"] is None
+
+    def test_no_opener_when_already_open(self, store_conn):
+        """If a period is already open, no new period is created."""
+        t1 = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        t2 = datetime(2026, 9, 1, 12, 5, 0, tzinfo=timezone.utc)
+
+        ensure_period_open(store_conn, t1)
+        ensure_period_open(store_conn, t2)
+
+        period = get_open_period(store_conn)
+        assert period is not None
+        assert period["started_at"] == "2026-09-01T12:00:00+00:00"
+
+    def test_never_backdated(self, store_conn):
+        """Period starts at the run moment, not the beginning of the hour."""
+        run_time = datetime(2026, 9, 1, 12, 3, 45, tzinfo=timezone.utc)
+        ensure_period_open(store_conn, run_time)
+
+        period = get_open_period(store_conn)
+        assert period["started_at"] == "2026-09-01T12:03:45+00:00"
+
+    def test_new_period_after_close(self, store_conn):
+        """After closing a period, next run opens a new one."""
+        t1 = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        t2 = datetime(2026, 9, 1, 13, 0, 0, tzinfo=timezone.utc)
+        t3 = datetime(2026, 9, 1, 14, 0, 0, tzinfo=timezone.utc)
+
+        ensure_period_open(store_conn, t1)
+        close_period(store_conn, t2, "user_disabled")
+        ensure_period_open(store_conn, t3)
+
+        period = get_open_period(store_conn)
+        assert period is not None
+        assert period["started_at"] == "2026-09-01T14:00:00+00:00"
+
+
+class TestClosePeriod:
+    """Spec §8.6: Pause closes with user_disabled."""
+
+    def test_close_with_user_disabled(self, store_conn):
+        t1 = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        t2 = datetime(2026, 9, 1, 13, 0, 0, tzinfo=timezone.utc)
+
+        ensure_period_open(store_conn, t1)
+        close_period(store_conn, t2, "user_disabled")
+
+        period = get_open_period(store_conn)
+        assert period is None
+
+        cursor = store_conn.execute(
+            "SELECT ended_at, end_cause FROM monitoring_periods WHERE id = 1"
+        )
+        row = cursor.fetchone()
+        assert row[0] == "2026-09-01T13:00:00+00:00"
+        assert row[1] == "user_disabled"
+
+    def test_close_nonexistent_is_noop(self, store_conn):
+        """Closing when no period is open is a no-op (spec §8.6 pause otherwise)."""
+        t = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        close_period(store_conn, t, "user_disabled")
+
+        cursor = store_conn.execute("SELECT COUNT(*) FROM monitoring_periods")
+        assert cursor.fetchone()[0] == 0
+
+
+class TestIsInsidePeriod:
+    """Spec §5.2: Wall-clock outside periods excluded from numerator/denominator."""
+
+    def test_inside_open_period(self, store_conn):
+        t_start = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        t_inside = datetime(2026, 9, 1, 12, 30, 0, tzinfo=timezone.utc)
+
+        ensure_period_open(store_conn, t_start)
+        assert is_inside_period(store_conn, t_inside) is True
+
+    def test_outside_closed_period(self, store_conn):
+        t_start = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        t_end = datetime(2026, 9, 1, 13, 0, 0, tzinfo=timezone.utc)
+        t_outside = datetime(2026, 9, 1, 14, 0, 0, tzinfo=timezone.utc)
+
+        ensure_period_open(store_conn, t_start)
+        close_period(store_conn, t_end, "user_disabled")
+        assert is_inside_period(store_conn, t_outside) is False
+
+    def test_outside_no_periods(self, store_conn):
+        t = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        assert is_inside_period(store_conn, t) is False
+
+    def test_inside_second_period(self, store_conn):
+        """Two periods with a gap; time in second period is inside."""
+        t1_start = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        t1_end = datetime(2026, 9, 1, 13, 0, 0, tzinfo=timezone.utc)
+        t2_start = datetime(2026, 9, 1, 14, 0, 0, tzinfo=timezone.utc)
+        t_inside = datetime(2026, 9, 1, 14, 30, 0, tzinfo=timezone.utc)
+
+        ensure_period_open(store_conn, t1_start)
+        close_period(store_conn, t1_end, "user_disabled")
+        ensure_period_open(store_conn, t2_start)
+        assert is_inside_period(store_conn, t_inside) is True

tests/test_preferences.py

@@ -0,0 +1,301 @@
+"""Tests for user-scoped TUI preferences (issue #80).
+
+Covers:
+  - Preference load/save with safe defaults
+  - XDG_CONFIG_HOME user-scoped persistence
+  - Amber default theme, normal-motion default
+  - Invalid/unreadable/unwritable preference data does not crash
+  - Theme presets: Amber, Nord, High Contrast
+  - Reduced motion preference persistence
+  - CLI status and collector behaviour unchanged by preferences
+"""
+import json
+import os
+from pathlib import Path
+from unittest.mock import patch
+
+import pytest
+import sys
+
+sys.path.insert(0, str(Path(__file__).parent.parent / "src"))
+
+from fenris.preferences import (
+    load_preferences,
+    save_preferences,
+    get_preference_path,
+    PREFERENCE_FILE_NAME,
+    VALID_THEMES,
+    DEFAULT_THEME,
+    DEFAULT_REDUCED_MOTION,
+)
+
+
+# ---------------------------------------------------------------------------
+# Helpers
+# ---------------------------------------------------------------------------
+
+def _make_prefs_dir(tmp_path: Path) -> Path:
+    """Create a fake XDG_CONFIG_HOME with fenris subdir."""
+    config_home = tmp_path / ".config"
+    config_home.mkdir(parents=True, exist_ok=True)
+    return config_home
+
+
+# ---------------------------------------------------------------------------
+# Preference path tests
+# ---------------------------------------------------------------------------
+
+class TestPreferencePath:
+    """Preference file lives at XDG_CONFIG_HOME/fenris/preferences.json."""
+
+    def test_uses_xdg_config_home(self, tmp_path):
+        """Path respects XDG_CONFIG_HOME environment variable."""
+        config_home = _make_prefs_dir(tmp_path)
+        with patch.dict(os.environ, {"XDG_CONFIG_HOME": str(config_home)}):
+            path = get_preference_path()
+            assert path == config_home / "fenris" / PREFERENCE_FILE_NAME
+
+    def test_default_path_fallback(self):
+        """When XDG_CONFIG_HOME is unset, falls back to ~/.config."""
+        with patch.dict(os.environ, {}, clear=True):
+            # Remove XDG_CONFIG_HOME if present
+            os.environ.pop("XDG_CONFIG_HOME", None)
+            path = get_preference_path()
+            assert "fenris" in str(path)
+            assert PREFERENCE_FILE_NAME in str(path)
+
+
+# ---------------------------------------------------------------------------
+# Default preferences tests
+# ---------------------------------------------------------------------------
+
+class TestDefaults:
+    """When no preference file exists, defaults are returned."""
+
+    def test_default_theme_is_amber(self):
+        """Amber is the default theme preset."""
+        assert DEFAULT_THEME == "amber"
+
+    def test_default_reduced_motion_is_false(self):
+        """Normal motion is the default."""
+        assert DEFAULT_REDUCED_MOTION is False
+
+    def test_valid_themes_are_all_presets(self):
+        """Three valid presets exist."""
+        assert VALID_THEMES == {"amber", "nord", "high_contrast"}
+
+    def test_load_returns_defaults_when_no_file(self, tmp_path):
+        """Missing preference file returns safe defaults."""
+        with patch.dict(os.environ, {"XDG_CONFIG_HOME": str(tmp_path)}):
+            prefs = load_preferences()
+            assert prefs["theme"] == "amber"
+            assert prefs["reduced_motion"] is False
+
+
+# ---------------------------------------------------------------------------
+# Save and load round-trip tests
+# ---------------------------------------------------------------------------
+
+class TestRoundTrip:
+    """Preferences survive save → load."""
+
+    def test_save_and_load_basic(self, tmp_path):
+        """Basic theme and motion save/load."""
+        config_home = _make_prefs_dir(tmp_path)
+        with patch.dict(os.environ, {"XDG_CONFIG_HOME": str(config_home)}):
+            save_preferences(theme="nord", reduced_motion=True)
+            prefs = load_preferences()
+            assert prefs["theme"] == "nord"
+            assert prefs["reduced_motion"] is True
+
+    def test_save_creates_directory(self, tmp_path):
+        """Save creates the fenris config directory if missing."""
+        config_home = tmp_path / ".config"
+        with patch.dict(os.environ, {"XDG_CONFIG_HOME": str(config_home)}):
+            save_preferences(theme="amber", reduced_motion=False)
+            assert (config_home / "fenris" / PREFERENCE_FILE_NAME).exists()
+
+    def test_overwrites_existing(self, tmp_path):
+        """Second save overwrites the first."""
+        config_home = _make_prefs_dir(tmp_path)
+        with patch.dict(os.environ, {"XDG_CONFIG_HOME": str(config_home)}):
+            save_preferences(theme="amber", reduced_motion=False)
+            save_preferences(theme="high_contrast", reduced_motion=True)
+            prefs = load_preferences()
+            assert prefs["theme"] == "high_contrast"
+            assert prefs["reduced_motion"] is True
+
+    def test_all_themes_round_trip(self, tmp_path):
+        """Every valid theme saves and loads correctly."""
+        config_home = _make_prefs_dir(tmp_path)
+        for theme in VALID_THEMES:
+            with patch.dict(os.environ, {"XDG_CONFIG_HOME": str(config_home)}):
+                save_preferences(theme=theme, reduced_motion=False)
+                prefs = load_preferences()
+                assert prefs["theme"] == theme
+
+
+# ---------------------------------------------------------------------------
+# Safe failure tests — invalid/unreadable/unwritable
+# ---------------------------------------------------------------------------
+
+class TestSafeFailures:
+    """Invalid data never crashes the dashboard."""
+
+    def test_corrupt_json_returns_defaults(self, tmp_path):
+        """Malformed JSON returns safe defaults."""
+        config_home = _make_prefs_dir(tmp_path)
+        fenris_dir = config_home / "fenris"
+        fenris_dir.mkdir(parents=True, exist_ok=True)
+        (fenris_dir / PREFERENCE_FILE_NAME).write_text("{corrupt json!!")
+
+        with patch.dict(os.environ, {"XDG_CONFIG_HOME": str(config_home)}):
+            prefs = load_preferences()
+            assert prefs["theme"] == "amber"
+            assert prefs["reduced_motion"] is False
+
+    def test_unknown_theme_returns_default(self, tmp_path):
+        """Unrecognized theme value falls back to amber."""
+        config_home = _make_prefs_dir(tmp_path)
+        fenris_dir = config_home / "fenris"
+        fenris_dir.mkdir(parents=True, exist_ok=True)
+        (fenris_dir / PREFERENCE_FILE_NAME).write_text(
+            json.dumps({"theme": "neon-pink", "reduced_motion": False})
+        )
+
+        with patch.dict(os.environ, {"XDG_CONFIG_HOME": str(config_home)}):
+            prefs = load_preferences()
+            assert prefs["theme"] == "amber"
+
+    def test_missing_keys_get_defaults(self, tmp_path):
+        """Partial preference file fills in missing keys."""
+        config_home = _make_prefs_dir(tmp_path)
+        fenris_dir = config_home / "fenris"
+        fenris_dir.mkdir(parents=True, exist_ok=True)
+        (fenris_dir / PREFERENCE_FILE_NAME).write_text(
+            json.dumps({"theme": "nord"})
+        )
+
+        with patch.dict(os.environ, {"XDG_CONFIG_HOME": str(config_home)}):
+            prefs = load_preferences()
+            assert prefs["theme"] == "nord"
+            assert prefs["reduced_motion"] is False
+
+    def test_unreadable_file_returns_defaults(self, tmp_path):
+        """Permission denied on preference file returns defaults."""
+        config_home = _make_prefs_dir(tmp_path)
+        fenris_dir = config_home / "fenris"
+        fenris_dir.mkdir(parents=True, exist_ok=True)
+        pref_file = fenris_dir / PREFERENCE_FILE_NAME
+        pref_file.write_text(json.dumps({"theme": "nord"}))
+        pref_file.chmod(0o000)
+
+        with patch.dict(os.environ, {"XDG_CONFIG_HOME": str(config_home)}):
+            prefs = load_preferences()
+            # Should fall back to defaults without crashing
+            assert prefs["theme"] in VALID_THEMES
+
+    def test_unwritable_location_returns_defaults(self, tmp_path):
+        """Read-only config directory returns defaults without crashing."""
+        config_home = _make_prefs_dir(tmp_path)
+        fenris_dir = config_home / "fenris"
+        fenris_dir.mkdir(parents=True, exist_ok=True)
+        fenris_dir.chmod(0o555)
+
+        with patch.dict(os.environ, {"XDG_CONFIG_HOME": str(config_home)}):
+            # Should not raise
+            save_preferences(theme="nord", reduced_motion=True)
+            prefs = load_preferences()
+            # Either saved successfully or fell back — either way, no crash
+            assert prefs["theme"] in VALID_THEMES
+
+    def test_non_json_file_returns_defaults(self, tmp_path):
+        """A file that isn't JSON returns defaults."""
+        config_home = _make_prefs_dir(tmp_path)
+        fenris_dir = config_home / "fenris"
+        fenris_dir.mkdir(parents=True, exist_ok=True)
+        (fenris_dir / PREFERENCE_FILE_NAME).write_text("this is not json")
+
+        with patch.dict(os.environ, {"XDG_CONFIG_HOME": str(config_home)}):
+            prefs = load_preferences()
+            assert prefs["theme"] == "amber"
+
+    def test_wrong_type_for_reduced_motion(self, tmp_path):
+        """Non-boolean reduced_motion falls back to default."""
+        config_home = _make_prefs_dir(tmp_path)
+        fenris_dir = config_home / "fenris"
+        fenris_dir.mkdir(parents=True, exist_ok=True)
+        (fenris_dir / PREFERENCE_FILE_NAME).write_text(
+            json.dumps({"theme": "amber", "reduced_motion": "yes"})
+        )
+
+        with patch.dict(os.environ, {"XDG_CONFIG_HOME": str(config_home)}):
+            prefs = load_preferences()
+            assert prefs["reduced_motion"] is False
+
+
+# ---------------------------------------------------------------------------
+# CLI/collector isolation tests
+# ---------------------------------------------------------------------------
+
+class TestCLIIsolation:
+    """TUI display preferences do not affect CLI status or collector."""
+
+    def test_cli_status_ignores_preferences(self, tmp_path):
+        """fenris status output is independent of TUI preferences."""
+        from fenris.status import get_status
+
+        # Create a valid store with data
+        from fenris.store import init_store
+        conn = init_store(tmp_path / "test.db")
+        conn.execute(
+            "INSERT INTO samples (ts, device, data_units_written, data_units_read, "
+            "percentage_used, bytes_written, bytes_read, power_on_hours) "
+            "VALUES (?, ?, ?, ?, ?, ?, ?, ?)",
+            ("2026-09-30T10:00:00+00:00", "/dev/nvme0n1", 1000000, 500000,
+             5, 512000000000, 256000000000, 8765),
+        )
+        conn.commit()
+        conn.close()
+
+        # Save non-default preferences
+        config_home = _make_prefs_dir(tmp_path)
+        with patch.dict(os.environ, {"XDG_CONFIG_HOME": str(config_home)}):
+            save_preferences(theme="high_contrast", reduced_motion=True)
+            status_text = get_status(
+                store_path=tmp_path / "test.db",
+                clock_now=datetime(2026, 9, 30, 12, 0, 0, tzinfo=timezone.utc),
+                query_services=False,
+                query_journal=False,
+            )
+            # Status output should NOT contain theme names or motion settings
+            assert "high_contrast" not in status_text.lower()
+            assert "reduced_motion" not in status_text.lower()
+            assert "amber" not in status_text.lower()
+
+    def test_preferences_do_not_alter_store(self, tmp_path):
+        """Saving preferences never writes to the observation store."""
+        import sqlite3
+        config_home = _make_prefs_dir(tmp_path)
+        store_path = tmp_path / "observations.db"
+
+        from fenris.store import init_store
+        conn = init_store(store_path)
+        # Record store state before preference save
+        cursor = conn.execute("SELECT name FROM sqlite_master WHERE type='table'")
+        tables_before = sorted(r[0] for r in cursor.fetchall())
+        conn.close()
+
+        with patch.dict(os.environ, {"XDG_CONFIG_HOME": str(config_home)}):
+            save_preferences(theme="nord", reduced_motion=True)
+
+        # Store schema should be unchanged
+        conn = sqlite3.connect(store_path)
+        cursor = conn.execute("SELECT name FROM sqlite_master WHERE type='table'")
+        tables_after = sorted(r[0] for r in cursor.fetchall())
+        conn.close()
+        assert tables_before == tables_after
+
+
+# Need datetime for CLI isolation test
+from datetime import datetime, timezone

tests/test_pruning.py

@@ -0,0 +1,155 @@
+"""Raw sample pruning tests.
+
+Spec §3.4, ST-5: Raw samples pruned to 14 days; hour observations and
+day aggregates are retained indefinitely.
+
+Issue #74: Boundary anchors required for successor evidence are retained.
+"""
+import sqlite3
+import sys
+from datetime import datetime, timezone, timedelta
+from pathlib import Path
+
+import pytest
+
+sys.path.insert(0, str(Path(__file__).parent.parent / "src"))
+
+from fenris.store import init_store
+from fenris.pruning import prune_old_samples
+
+
+@pytest.fixture
+def store_conn(tmp_path: Path):
+    db_path = tmp_path / "test.db"
+    conn = init_store(db_path)
+    yield conn
+    conn.close()
+
+
+def _insert_sample(conn, ts_iso, device="/dev/nvme0"):
+    conn.execute(
+        "INSERT INTO samples (ts, device, data_units_written, data_units_read, "
+        " bytes_written, bytes_read, percentage_used) VALUES (?, ?, 0, 0, 0, 0, 0)",
+        (ts_iso, device),
+    )
+    conn.commit()
+
+
+class TestPruneOldSamples:
+    """Spec §3.4: Raw samples pruned to 14 days."""
+
+    def test_keeps_recent_samples(self, store_conn):
+        now = datetime(2026, 9, 15, 12, 0, 0, tzinfo=timezone.utc)
+        # Insert a sample 1 day ago
+        ts = (now - timedelta(days=1)).isoformat()
+        _insert_sample(store_conn, ts)
+
+        pruned = prune_old_samples(store_conn, now, retention_days=14)
+        assert pruned == 0
+
+        cursor = store_conn.execute("SELECT COUNT(*) FROM samples")
+        assert cursor.fetchone()[0] == 1
+
+    def test_removes_old_samples(self, store_conn):
+        now = datetime(2026, 9, 15, 12, 0, 0, tzinfo=timezone.utc)
+        # Insert samples at 10, 14, and 15 days ago
+        # All three are before the cutoff (2026-09-01T12:00:00)
+        # The 15-day-old sample is not a boundary anchor because
+        # the next sample (14 days ago) is also before the cutoff
+        for days_ago in [10, 14, 15]:
+            ts = (now - timedelta(days=days_ago)).isoformat()
+            _insert_sample(store_conn, ts)
+
+        pruned = prune_old_samples(store_conn, now, retention_days=14)
+        assert pruned == 1  # Only the 15-day-old sample removed
+
+        cursor = store_conn.execute("SELECT COUNT(*) FROM samples")
+        assert cursor.fetchone()[0] == 2
+
+    def test_removes_many_old_samples(self, store_conn):
+        now = datetime(2026, 9, 15, 12, 0, 0, tzinfo=timezone.utc)
+        for days_ago in range(1, 30):
+            ts = (now - timedelta(days=days_ago)).isoformat()
+            _insert_sample(store_conn, ts)
+
+        pruned = prune_old_samples(store_conn, now, retention_days=14)
+        assert pruned == 15  # Days 15-29 removed
+
+        cursor = store_conn.execute("SELECT COUNT(*) FROM samples")
+        assert cursor.fetchone()[0] == 14  # Days 1-14 kept
+
+    def test_empty_store_no_error(self, store_conn):
+        now = datetime(2026, 9, 15, 12, 0, 0, tzinfo=timezone.utc)
+        pruned = prune_old_samples(store_conn, now, retention_days=14)
+        assert pruned == 0
+
+    def test_hour_observations_not_pruned(self, store_conn):
+        """Hour observations are retained indefinitely."""
+        now = datetime(2026, 9, 15, 12, 0, 0, tzinfo=timezone.utc)
+        # Insert an old sample and a recent sample
+        # The old sample is a boundary anchor (needed for derivation)
+        _insert_sample(store_conn, (now - timedelta(days=20)).isoformat())
+        _insert_sample(store_conn, (now - timedelta(days=1)).isoformat())
+
+        # Insert an old hour observation
+        store_conn.execute(
+            "INSERT INTO hour_observations (hour, active_seconds, sample_count) "
+            "VALUES (?, 3600, 1)",
+            ((now - timedelta(days=20)).replace(hour=0, minute=0, second=0).isoformat(),),
+        )
+        store_conn.commit()
+
+        prune_old_samples(store_conn, now, retention_days=14)
+
+        # Old sample is retained as boundary anchor (needed for derivation)
+        cursor = store_conn.execute("SELECT COUNT(*) FROM samples")
+        assert cursor.fetchone()[0] == 2
+
+        # Hour observation retained
+        cursor = store_conn.execute("SELECT COUNT(*) FROM hour_observations")
+        assert cursor.fetchone()[0] == 1
+
+    def test_boundary_anchor_retained(self, store_conn):
+        """Boundary anchors required for derivation are retained."""
+        now = datetime(2026, 9, 30, 12, 0, 0, tzinfo=timezone.utc)
+        
+        # Old sample before boundary (2026-09-14T23:55:00)
+        # is 15 days and 0.75 hours old (before cutoff at 2026-09-16T12:00:00)
+        _insert_sample(store_conn, "2026-09-14T23:55:00+00:00", 1000000)
+        
+        # Sample after boundary (2026-09-16T12:30:00)
+        # is 13 days and 23.5 hours old (within retention)
+        _insert_sample(store_conn, "2026-09-16T12:30:00+00:00", 2000000)
+        
+        # Run pruning
+        pruned = prune_old_samples(store_conn, now, retention_days=14)
+        
+        # The boundary anchor should be retained
+        cursor = store_conn.execute(
+            "SELECT COUNT(*) FROM samples WHERE ts = '2026-09-14T23:55:00+00:00'"
+        )
+        assert cursor.fetchone()[0] == 1
+
+    def test_old_sample_with_derived_interval_removed(self, store_conn):
+        """Old samples with fully derived intervals are removed."""
+        now = datetime(2026, 9, 30, 12, 0, 0, tzinfo=timezone.utc)
+        
+        # Old sample with derived interval
+        _insert_sample(store_conn, "2026-09-10T10:00:00+00:00", 1000000)
+        _insert_sample(store_conn, "2026-09-10T10:30:00+00:00", 2000000)
+        
+        # Hour observation exists for the interval
+        store_conn.execute(
+            "INSERT INTO hour_observations (hour, active_seconds, bytes_written_delta, bytes_read_delta, sample_count, coverage) "
+            "VALUES ('2026-09-10T10:00:00+00:00', 3600, 1000000, 0, 1, 1.0)",
+        )
+        store_conn.commit()
+        
+        # Run pruning
+        pruned = prune_old_samples(store_conn, now, retention_days=14)
+        
+        # Old sample should be removed (interval is derived)
+        cursor = store_conn.execute(
+            "SELECT COUNT(*) FROM samples WHERE ts = '2026-09-10T10:00:00+00:00'"
+        )
+        assert cursor.fetchone()[0] == 0

tests/test_release.py

@@ -0,0 +1,390 @@
+"""Release flow tests (issue #52).
+
+Tests the one-command release flow: build, sign, publish, and attach — with
+dry-run mode that is what the tests assert.  All assertions are structural:
+dry-run output contains the expected commands without any network or registry
+access.
+
+Requirements:
+  - scripts/release.sh exists and is executable
+  - No network access required for dry-run tests
+  - No GPG key or registry token required for dry-run tests
+
+Spec: release-packaging.md §5, issue #52 acceptance criteria
+"""
+import subprocess
+from pathlib import Path
+
+import pytest
+
+REPO_ROOT = Path(__file__).resolve().parent.parent
+RELEASE_SCRIPT = REPO_ROOT / "scripts" / "release.sh"
+
+
+# ---------------------------------------------------------------------------
+# Helpers
+# ---------------------------------------------------------------------------
+
+def _read(path: str | Path) -> str:
+    from tests.conftest import read
+    return read(path)
+
+
+def _get_version() -> str:
+    """Extract version from pyproject.toml."""
+    from tests.conftest import get_version
+    return get_version()
+
+
+def _run_dry_run(*args: str) -> tuple[int, str]:
+    """Run the release script in dry-run mode and return (exit_code, stdout)."""
+    cmd = ["bash", str(RELEASE_SCRIPT), "--dry-run"] + list(args)
+    r = subprocess.run(
+        cmd, capture_output=True, text=True, timeout=30,
+        cwd=REPO_ROOT,
+    )
+    return r.returncode, r.stdout + r.stderr
+
+
+def _deb_filename(version: str, release: int = 1) -> str:
+    """Expected deb filename for a given version and release."""
+    return f"fenris_{version}_amd64.deb"
+
+
+def _rpm_filename(version: str, release: int = 1) -> str:
+    """Expected RPM filename for a given version and release."""
+    return f"fenris-{version}-{release}.x86_64.rpm"
+
+
+def _registry_upload_deb_url(version: str) -> str:
+    """Expected registry upload URL for a deb package."""
+    return f"debian/pool/bookworm/main/upload"
+
+
+def _registry_upload_rpm_url() -> str:
+    """Expected registry upload URL for an RPM package."""
+    return "rpm/fenris/upload"
+
+
+# ---------------------------------------------------------------------------
+# Tests — release script existence and permissions
+# ---------------------------------------------------------------------------
+
+class TestReleaseScriptExists:
+    """Verify the release script is present and executable."""
+
+    def test_script_exists(self):
+        assert RELEASE_SCRIPT.exists(), \
+            "scripts/release.sh must exist"
+
+    def test_script_is_executable(self):
+        assert RELEASE_SCRIPT.stat().st_mode & 0o111, \
+            "scripts/release.sh must be executable"
+
+    def test_script_has_shebang(self):
+        first_line = RELEASE_SCRIPT.read_text().splitlines()[0]
+        assert first_line.startswith("#!/"), \
+            "scripts/release.sh must have a shebang"
+
+
+# ---------------------------------------------------------------------------
+# Tests — dry-run prints all expected commands
+# ---------------------------------------------------------------------------
+
+class TestDryRunCommandPrintout:
+    """Verify dry-run prints every command that would execute."""
+
+    def test_dry_run_exits_zero(self):
+        rc, _ = _run_dry_run()
+        assert rc == 0, "Dry-run must exit zero"
+
+    def test_dry_run_prints_make_package(self):
+        _, output = _run_dry_run()
+        assert "make" in output.lower() and "package" in output.lower(), \
+            "Dry-run must print the make package command"
+
+    def test_dry_run_prints_rpm_signing(self):
+        _, output = _run_dry_run()
+        assert "rpmsign" in output or "sign" in output.lower(), \
+            "Dry-run must print RPM signing step"
+
+    def test_dry_run_prints_sha256sums(self):
+        _, output = _run_dry_run()
+        assert "sha256sum" in output, \
+            "Dry-run must print SHA256SUMS generation"
+
+    def test_dry_run_prints_clearsign(self):
+        _, output = _run_dry_run()
+        assert "clearsign" in output or "SHA256SUMS.asc" in output, \
+            "Dry-run must print clearsign step"
+
+    def test_dry_run_prints_deb_upload(self):
+        version = _get_version()
+        _, output = _run_dry_run()
+        assert _registry_upload_deb_url(version) in output, \
+            f"Dry-run must print deb upload URL ({_registry_upload_deb_url(version)})"
+
+    def test_dry_run_prints_deb_upload_for_all_codenames(self):
+        _, output = _run_dry_run()
+        for codename in ("bookworm", "jammy", "noble"):
+            assert codename in output, \
+                f"Dry-run must include upload for {codename}"
+
+    def test_dry_run_prints_rpm_upload(self):
+        _, output = _run_dry_run()
+        assert _registry_upload_rpm_url() in output, \
+            f"Dry-run must print RPM upload URL ({_registry_upload_rpm_url()})"
+
+    def test_dry_run_prints_release_creation(self):
+        _, output = _run_dry_run()
+        assert "release" in output.lower(), \
+            "Dry-run must print release creation step"
+
+    def test_dry_run_prints_attachment_upload(self):
+        _, output = _run_dry_run()
+        assert "SHA256SUMS.asc" in output, \
+            "Dry-run must print SHA256SUMS.asc attachment upload"
+
+    def test_dry_run_prints_tag_push(self):
+        _, output = _run_dry_run()
+        # The tag is created atomically by the Gitea release API (step 5),
+        # not by a separate git push. Verify the release creation step is present.
+        assert "tag_name" in output or "release" in output.lower(), \
+            "Dry-run must print release creation (which creates the tag)"
+
+    def test_dry_run_no_network_calls(self):
+        """Dry-run must not execute curl, rpmsign, or any network tools."""
+        _, output = _run_dry_run()
+        # The dry-run mode prints a marker at the top; all commands are
+        # echoed (prefixed by spaces) but never executed.  Verify the
+        # marker is present, confirming we're in dry-run mode.
+        assert "[dry-run]" in output, \
+            "Output must contain [dry-run] marker"
+        # Verify dangerous tools only appear as printed commands (not executed).
+        # Printed commands are indented; the dry-run section header confirms
+        # no commands were actually run.
+        assert "Commands below will be executed" in output, \
+            "Dry-run must indicate commands are for display only"
+
+
+# ---------------------------------------------------------------------------
+# Tests — dry-run prints correct package filenames
+# ---------------------------------------------------------------------------
+
+class TestDryRunFilenames:
+    """Verify dry-run uses the correct artifact filenames."""
+
+    def test_deb_filename_in_output(self):
+        version = _get_version()
+        _, output = _run_dry_run()
+        expected = _deb_filename(version)
+        assert expected in output, \
+            f"Dry-run must reference deb filename {expected}"
+
+    def test_rpm_filename_in_output(self):
+        version = _get_version()
+        _, output = _run_dry_run()
+        expected = _rpm_filename(version)
+        assert expected in output, \
+            f"Dry-run must reference RPM filename {expected}"
+
+    def test_checksums_filename_in_output(self):
+        _, output = _run_dry_run()
+        assert "SHA256SUMS" in output, \
+            "Dry-run must reference SHA256SUMS filename"
+
+
+# ---------------------------------------------------------------------------
+# Tests — dry-run does not create artifacts or tags
+# ---------------------------------------------------------------------------
+
+class TestDryRunNoSideEffects:
+    """Verify dry-run creates no filesystem or git side effects."""
+
+    def test_dry_run_no_git_tag_created(self):
+        version = _get_version()
+        tag = f"v{version}"
+        # Ensure tag doesn't exist before
+        r = subprocess.run(
+            ["git", "tag", "-l", tag], capture_output=True, text=True,
+            cwd=REPO_ROOT,
+        )
+        pre_tags = r.stdout.strip()
+
+        _run_dry_run()
+
+        # Verify tag was not created
+        r = subprocess.run(
+            ["git", "tag", "-l", tag], capture_output=True, text=True,
+            cwd=REPO_ROOT,
+        )
+        post_tags = r.stdout.strip()
+        assert pre_tags == post_tags, \
+            f"Dry-run must not create git tag {tag}"
+
+
+# ---------------------------------------------------------------------------
+# Tests — revision bumping (structural: output contains incremented release)
+# ---------------------------------------------------------------------------
+
+class TestRevisionBumping:
+    """Verify the release script handles revision bumping.
+
+    When a version already exists in the registry (HTTP 409), the script
+    bumps the revision and retries.  These tests verify the dry-run output
+    reflects the correct revision logic — without any network access.
+    """
+
+    def test_dry_run_starts_at_revision_one(self):
+        version = _get_version()
+        _, output = _run_dry_run()
+        rpm_expected = _rpm_filename(version, 1)
+        assert rpm_expected in output, \
+            f"Dry-run must start at release 1: expected {rpm_expected} in output"
+
+    def test_revision_bump_changes_rpm_filename(self):
+        """When revision is bumped, the RPM filename changes accordingly."""
+        version = _get_version()
+        rpm_r1 = _rpm_filename(version, 1)
+        rpm_r2 = _rpm_filename(version, 2)
+        # R2 filename must differ from R1
+        assert rpm_r1 != rpm_r2, \
+            "R2 filename must differ from R1"
+        # Both must contain the version
+        assert version in rpm_r1
+        assert version in rpm_r2
+
+    def test_revision_bump_changes_deb_filename(self):
+        """When revision is bumped, the deb filename also changes."""
+        version = _get_version()
+        # Deb filename includes release in nfpm naming
+        deb_r1 = f"fenris_{version}_amd64.deb"
+        deb_r2 = f"fenris_{version}_amd64.deb"
+        # For deb, the filename doesn't change with revision (deb uses epoch)
+        # But the RPM does — this verifies we test RPM revision correctly
+        rpm_r1 = _rpm_filename(version, 1)
+        rpm_r2 = _rpm_filename(version, 2)
+        assert "-1." in rpm_r1, "R1 RPM must contain -1."
+        assert "-2." in rpm_r2, "R2 RPM must contain -2."
+
+
+# ---------------------------------------------------------------------------
+# Tests — bare tag prevention (structural)
+# ---------------------------------------------------------------------------
+
+class TestBareTagPrevention:
+    """Verify the flow prevents bare tags.
+
+    A bare tag (tag without packages, release entry, notes, and checksums)
+    must not result from the flow.  The script checks for existing bare
+    tags before proceeding.  These tests verify the dry-run doesn't create
+    any tags.
+    """
+
+    def test_dry_run_does_not_push_tag(self):
+        _, output = _run_dry_run()
+        # The dry-run marker confirms no commands are executed.
+        # git push appears only as a printed command, never executed.
+        assert "[dry-run]" in output, \
+            "Must be in dry-run mode"
+        # Tag push is printed but the [dry-run] marker confirms nothing ran
+        assert "Commands below will be executed" in output, \
+            "Dry-run must indicate commands are for display only"
+
+
+# ---------------------------------------------------------------------------
+# Tests — CI workflow file
+# ---------------------------------------------------------------------------
+
+class TestCIWorkflow:
+    """Verify the dormant CI workflow is present and correctly structured."""
+
+    def test_workflow_file_exists(self):
+        path = REPO_ROOT / ".gitea" / "workflows" / "release.yml"
+        assert path.exists(), \
+            ".gitea/workflows/release.yml must exist"
+
+    def test_workflow_triggers_on_tags(self):
+        content = _read(".gitea/workflows/release.yml")
+        assert "v*" in content, \
+            "Workflow must trigger on version tags (v*)"
+
+    def test_workflow_has_release_step(self):
+        content = _read(".gitea/workflows/release.yml")
+        assert "release" in content.lower(), \
+            "Workflow must have a release step"
+
+    def test_workflow_mentions_signing(self):
+        content = _read(".gitea/workflows/release.yml")
+        assert "sign" in content.lower(), \
+            "Workflow must include signing step"
+
+    def test_workflow_mentions_upload(self):
+        content = _read(".gitea/workflows/release.yml")
+        assert "upload" in content.lower() or "publish" in content.lower(), \
+            "Workflow must include upload/publish step"
+
+    def test_workflow_validates_notes_before_publication(self):
+        content = _read(".gitea/workflows/release.yml")
+        assert "scripts/extract_changelog.py" in content, \
+            "Workflow must fail before publication if release notes cannot be extracted"
+        assert "--footer packaging/release-footer.md" in content, \
+            "Workflow must assemble the body from the standing release footer"
+
+    def test_workflow_resynchronizes_existing_release_bodies(self):
+        content = _read(".gitea/workflows/release.yml")
+        assert "scripts/release_request.py" in content, \
+            "Workflow must make the create-versus-update decision through the request seam"
+        assert '"${METHOD}"' in content, \
+            "Workflow must execute the helper-selected create-or-update request"
+        assert 'RELEASE_PATH="$(printf' in content and '\n          PATH="$(printf' not in content, \
+            "Workflow must not overwrite the shell PATH while preparing the request URL"
+
+
+def test_readme_points_consumers_to_release_notes():
+    readme = _read("README.md")
+
+    assert "Per-release notes live on the [releases page]" in readme
+    assert "standing install and verification instructions" in readme
+
+
+# ---------------------------------------------------------------------------
+# Tests — Makefile release targets
+# ---------------------------------------------------------------------------
+
+class TestMakefileReleaseTargets:
+    """Verify the Makefile exposes release-related targets."""
+
+    def _makefile_content(self) -> str:
+        return _read("Makefile")
+
+    def test_release_run_target_exists(self):
+        content = self._makefile_content()
+        assert "release-run:" in content, \
+            "Makefile must have a release-run target"
+
+    def test_release_dry_run_target_exists(self):
+        content = self._makefile_content()
+        assert "release-dry-run:" in content, \
+            "Makefile must have a release-dry-run target"
+
+    def test_release_run_calls_script(self):
+        content = self._makefile_content()
+        assert "release.sh" in content, \
+            "release-run target must call scripts/release.sh"
+
+    def test_release_dry_run_uses_dry_run_flag(self):
+        content = self._makefile_content()
+        # Find the release-dry-run target and verify it passes --dry-run
+        in_target = False
+        for line in content.splitlines():
+            if line.startswith("release-dry-run:"):
+                in_target = True
+                continue
+            if in_target and line.strip():
+                if "--dry-run" in line:
+                    break
+                if not line.startswith("\t"):
+                    break
+        else:
+            pytest.fail("release-dry-run target must pass --dry-run to release.sh")

tests/test_repair.py

@@ -0,0 +1,398 @@
+"""Repair and retention tests (issue #74).
+
+Tests the idempotent, safe repair of hour observations and day aggregates
+from surviving raw samples, boundary anchor retention, and legacy summary
+handling at actual precision.
+"""
+import sqlite3
+import sys
+from datetime import datetime, timedelta, timezone
+from pathlib import Path
+
+import pytest
+
+sys.path.insert(0, str(Path(__file__).parent.parent / "src"))
+
+from fenris.store import init_store
+from fenris.repair import (
+    repair_derivation,
+    is_repair_in_progress,
+    get_repair_status,
+)
+from fenris.pruning import prune_old_samples, needs_boundary_anchor
+
+
+# ---------------------------------------------------------------------------
+# Fixtures
+# ---------------------------------------------------------------------------
+
+@pytest.fixture
+def store_conn(tmp_path: Path):
+    """Create a fresh store for each test."""
+    db_path = tmp_path / "test.db"
+    conn = init_store(db_path)
+    yield conn
+    conn.close()
+
+
+def _insert_sample(conn, ts_iso, bytes_written, bytes_read=0, power_on_hours=100,
+                   device="/dev/nvme0", segment_id=None):
+    """Insert a raw sample."""
+    conn.execute(
+        """INSERT INTO samples 
+           (ts, device, bytes_written, bytes_read, power_on_hours, 
+            data_units_written, data_units_read, segment_id)
+           VALUES (?, ?, ?, ?, ?, ?, ?, ?)""",
+        (ts_iso, device, bytes_written, bytes_read, power_on_hours,
+         bytes_written // 512000, bytes_read // 512000, segment_id),
+    )
+    conn.commit()
+
+
+def _insert_hour(conn, hour_iso, bytes_written_delta=0, active_seconds=3600,
+                 idle_seconds=0, powered_off_seconds=0, unknown_seconds=0,
+                 sample_count=1, coverage=1.0):
+    """Insert an hour observation."""
+    conn.execute(
+        """INSERT INTO hour_observations 
+           (hour, active_seconds, idle_seconds, powered_off_seconds, unknown_seconds,
+            bytes_written_delta, bytes_read_delta, sample_count, coverage)
+           VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)""",
+        (hour_iso, active_seconds, idle_seconds, powered_off_seconds, unknown_seconds,
+         bytes_written_delta, 0, sample_count, coverage),
+    )
+    conn.commit()
+
+
+def _insert_day_aggregate(conn, day, bytes_written_delta=0, coverage=1.0):
+    """Insert a day aggregate."""
+    conn.execute(
+        """INSERT INTO day_aggregates 
+           (day, active_seconds, bytes_written_delta, coverage, sample_count)
+           VALUES (?, 3600, ?, ?, 1)""",
+        (day, bytes_written_delta, coverage),
+    )
+    conn.commit()
+
+
+def _open_period(conn, start_iso, end_iso=None, end_cause=None):
+    """Insert a monitoring period."""
+    conn.execute(
+        """INSERT INTO monitoring_periods (started_at, ended_at, end_cause)
+           VALUES (?, ?, ?)""",
+        (start_iso, end_iso, end_cause),
+    )
+    conn.commit()
+
+
+# ---------------------------------------------------------------------------
+# AC1: Normal collection, legacy import and recovery use same evidence rules
+# ---------------------------------------------------------------------------
+
+class TestRepairUsesSameEvidenceRules:
+    """AC1: Repair derives only surviving supported evidence, transactionally
+    and idempotently."""
+
+    def test_repair_idempotent_on_empty_store(self, store_conn):
+        """Repair on empty store succeeds and does nothing."""
+        result = repair_derivation(store_conn)
+        assert result.ok is True
+        assert result.hours_created == 0
+        assert result.days_created == 0
+
+    def test_repair_idempotent_on_fully_derived(self, store_conn):
+        """Repair on store with existing derived data does not duplicate."""
+        now = datetime(2026, 9, 15, 12, 0, 0, tzinfo=timezone.utc)
+        _open_period(store_conn, "2026-09-14T00:00:00+00:00")
+        
+        # Insert samples that span an hour
+        _insert_sample(store_conn, "2026-09-14T10:00:00+00:00", 1000000)
+        _insert_sample(store_conn, "2026-09-14T10:30:00+00:00", 2000000)
+        
+        # Pre-existing hour observation for the 10:00 hour
+        # This hour observation captures the interval [10:00, 10:30]
+        _insert_hour(store_conn, "2026-09-14T10:00:00+00:00", 
+                     bytes_written_delta=1000000)
+        _insert_day_aggregate(store_conn, "2026-09-14", 
+                             bytes_written_delta=1000000)
+        
+        # Run repair
+        result = repair_derivation(store_conn)
+        
+        # Should not create new observations (already exist)
+        assert result.hours_created == 0
+        assert result.days_created == 0
+        
+        # Verify no duplicates
+        cursor = store_conn.execute(
+            "SELECT COUNT(*) FROM hour_observations WHERE hour = '2026-09-14T10:00:00+00:00'"
+        )
+        assert cursor.fetchone()[0] == 1
+
+    def test_repair_preserves_import_markers(self, store_conn):
+        """Repair does not remove legacy import markers."""
+        # Set legacy import marker
+        store_conn.execute(
+            "INSERT INTO store_metadata (key, value) VALUES ('legacy_imported', 'true')"
+        )
+        store_conn.commit()
+        
+        # Run repair
+        result = repair_derivation(store_conn)
+        
+        # Verify marker preserved
+        cursor = store_conn.execute(
+            "SELECT value FROM store_metadata WHERE key = 'legacy_imported'"
+        )
+        assert cursor.fetchone()[0] == "true"
+
+
+# ---------------------------------------------------------------------------
+# AC2: Rerunning or interrupting repair produces no duplicates
+# ---------------------------------------------------------------------------
+
+class TestRepairIdempotency:
+    """AC2: No duplicated intervals or totals from repeated repair."""
+
+    def test_repair_no_duplicate_hours(self, store_conn):
+        """Running repair twice produces no duplicate hour observations."""
+        _open_period(store_conn, "2026-09-14T00:00:00+00:00")
+        _insert_sample(store_conn, "2026-09-14T10:00:00+00:00", 1000000)
+        _insert_sample(store_conn, "2026-09-14T10:30:00+00:00", 2000000)
+        
+        # First repair
+        result1 = repair_derivation(store_conn)
+        assert result1.hours_created == 1
+        
+        # Second repair
+        result2 = repair_derivation(store_conn)
+        assert result2.hours_created == 0  # No new hours
+        
+        # Verify only one hour observation
+        cursor = store_conn.execute("SELECT COUNT(*) FROM hour_observations")
+        assert cursor.fetchone()[0] == 1
+
+    def test_repair_no_duplicate_days(self, store_conn):
+        """Running repair twice produces no duplicate day aggregates."""
+        _open_period(store_conn, "2026-09-14T00:00:00+00:00")
+        _insert_sample(store_conn, "2026-09-14T10:00:00+00:00", 1000000)
+        _insert_sample(store_conn, "2026-09-14T10:30:00+00:00", 2000000)
+        
+        # First repair
+        result1 = repair_derivation(store_conn)
+        assert result1.days_created == 1
+        
+        # Second repair
+        result2 = repair_derivation(store_conn)
+        assert result2.days_created == 0  # No new days
+        
+        # Verify only one day aggregate
+        cursor = store_conn.execute("SELECT COUNT(*) FROM day_aggregates")
+        assert cursor.fetchone()[0] == 1
+
+    def test_interrupted_repair_preserves_evidence(self, store_conn):
+        """If repair fails, prior valid history is preserved."""
+        _open_period(store_conn, "2026-09-14T00:00:00+00:00")
+        
+        # Insert valid existing data
+        _insert_hour(store_conn, "2026-09-14T10:00:00+00:00", 
+                     bytes_written_delta=500000)
+        _insert_day_aggregate(store_conn, "2026-09-14", 
+                             bytes_written_delta=500000)
+        
+        # Run repair (should succeed but not modify existing valid data)
+        result = repair_derivation(store_conn)
+        assert result.ok is True
+        
+        # Verify existing data preserved
+        cursor = store_conn.execute(
+            "SELECT bytes_written_delta FROM hour_observations "
+            "WHERE hour = '2026-09-14T10:00:00+00:00'"
+        )
+        assert cursor.fetchone()[0] == 500000
+
+
+# ---------------------------------------------------------------------------
+# AC3: Boundary anchor retention
+# ---------------------------------------------------------------------------
+
+class TestBoundaryAnchorRetention:
+    """AC3: Prune samples only after durable derivation; retain anchors."""
+
+    def test_needs_boundary_anchor_sample(self, store_conn):
+        """Sample before 14-day boundary is needed for derivation."""
+        now = datetime(2026, 9, 30, 12, 0, 0, tzinfo=timezone.utc)
+        
+        # Sample just before 14-day boundary (2026-09-15T23:55:00)
+        # is 14 days and 0.75 hours old (before cutoff at 2026-09-16T12:00:00)
+        _insert_sample(store_conn, "2026-09-15T23:55:00+00:00", 1000000)
+        
+        # Sample just after boundary (2026-09-16T12:30:00)
+        # is 13 days and 23.5 hours old (within retention)
+        _insert_sample(store_conn, "2026-09-16T12:30:00+00:00", 2000000)
+        
+        # The sample at 2026-09-15 is a boundary anchor because
+        # the interval spans the retention boundary
+        assert needs_boundary_anchor(store_conn, "2026-09-15T23:55:00+00:00", now)
+
+    def test_not_boundary_anchor_if_fully_derived(self, store_conn):
+        """Sample that's fully derived is not a boundary anchor."""
+        now = datetime(2026, 9, 30, 12, 0, 0, tzinfo=timezone.utc)
+        
+        # Insert sample and fully derive its interval
+        _insert_sample(store_conn, "2026-09-14T10:00:00+00:00", 1000000)
+        _insert_sample(store_conn, "2026-09-14T10:30:00+00:00", 2000000)
+        
+        # Hour observation already exists for this interval
+        _insert_hour(store_conn, "2026-09-14T10:00:00+00:00", 
+                     bytes_written_delta=1000000)
+        
+        # Not a boundary anchor
+        assert not needs_boundary_anchor(store_conn, "2026-09-14T10:00:00+00:00", now)
+
+    def test_pruning_retains_boundary_anchors(self, store_conn):
+        """Pruning keeps samples needed as boundary anchors."""
+        now = datetime(2026, 9, 30, 12, 0, 0, tzinfo=timezone.utc)
+        
+        # Old sample before boundary (2026-09-14T23:55:00)
+        # is 15 days and 0.75 hours old (before cutoff at 2026-09-16T12:00:00)
+        _insert_sample(store_conn, "2026-09-14T23:55:00+00:00", 1000000)
+        
+        # Sample after boundary (2026-09-16T12:30:00)
+        # is 13 days and 23.5 hours old (within retention)
+        _insert_sample(store_conn, "2026-09-16T12:30:00+00:00", 2000000)
+        
+        # Recent sample
+        _insert_sample(store_conn, "2026-09-29T12:00:00+00:00", 3000000)
+        
+        # Run pruning
+        pruned = prune_old_samples(store_conn, now, retention_days=14)
+        
+        # The boundary anchor should be retained
+        cursor = store_conn.execute(
+            "SELECT COUNT(*) FROM samples WHERE ts = '2026-09-14T23:55:00+00:00'"
+        )
+        assert cursor.fetchone()[0] == 1
+
+    def test_pruning_removes_old_sample_with_derived_interval(self, store_conn):
+        """Pruning removes old samples when interval is fully derived."""
+        now = datetime(2026, 9, 30, 12, 0, 0, tzinfo=timezone.utc)
+        
+        # Old sample with derived interval
+        _insert_sample(store_conn, "2026-09-10T10:00:00+00:00", 1000000)
+        _insert_sample(store_conn, "2026-09-10T10:30:00+00:00", 2000000)
+        
+        # Hour observation exists for the interval
+        _insert_hour(store_conn, "2026-09-10T10:00:00+00:00", 
+                     bytes_written_delta=1000000)
+        
+        # Run pruning
+        pruned = prune_old_samples(store_conn, now, retention_days=14)
+        
+        # Old sample should be removed (interval is derived)
+        cursor = store_conn.execute(
+            "SELECT COUNT(*) FROM samples WHERE ts = '2026-09-10T10:00:00+00:00'"
+        )
+        assert cursor.fetchone()[0] == 0
+
+
+# ---------------------------------------------------------------------------
+# AC4: Legacy day-only summaries retain actual precision
+# ---------------------------------------------------------------------------
+
+class TestLegacySummaryPrecision:
+    """AC4: Legacy summaries at actual precision, no interpolation."""
+
+    def test_legacy_summary_not_reconstructed(self, store_conn):
+        """Legacy day-only summaries are not interpolated to hour detail."""
+        # Insert a legacy-style day aggregate without hour observations
+        _insert_day_aggregate(store_conn, "2026-08-01", 
+                             bytes_written_delta=5000000)
+        
+        # Run repair
+        result = repair_derivation(store_conn)
+        
+        # Should not create hour observations for legacy day
+        cursor = store_conn.execute(
+            "SELECT COUNT(*) FROM hour_observations WHERE hour LIKE '2026-08-01%'"
+        )
+        assert cursor.fetchone()[0] == 0
+
+    def test_legacy_summary_no_double_counting(self, store_conn):
+        """Legacy summaries and derived intervals don't double-count."""
+        # Insert legacy day aggregate
+        _insert_day_aggregate(store_conn, "2026-08-01", 
+                             bytes_written_delta=5000000)
+        
+        # Run repair
+        result = repair_derivation(store_conn)
+        
+        # Day aggregate should not be modified
+        cursor = store_conn.execute(
+            "SELECT bytes_written_delta FROM day_aggregates WHERE day = '2026-08-01'"
+        )
+        assert cursor.fetchone()[0] == 5000000
+
+
+# ---------------------------------------------------------------------------
+# AC5: Status distinguishes evidence states
+# ---------------------------------------------------------------------------
+
+class TestStatusEvidenceDistingushing:
+    """AC5: Read-only views distinguish evidence states."""
+
+    def test_repair_status_available(self, store_conn):
+        """Repair status is available for read-only views."""
+        status = get_repair_status(store_conn)
+        assert hasattr(status, 'last_repair')
+        assert hasattr(status, 'repair_in_progress')
+        assert hasattr(status, 'hours_derived')
+        assert hasattr(status, 'days_derived')
+
+    def test_repair_in_progress_flag(self, store_conn):
+        """Repair in progress flag is trackable."""
+        assert not is_repair_in_progress(store_conn)
+
+
+# ---------------------------------------------------------------------------
+# AC6: Migration then collection then reader consumption
+# ---------------------------------------------------------------------------
+
+class TestMigrationCollectionReader:
+    """AC6: End-to-end migration, collection, and reader consumption."""
+
+    def test_store_with_raw_evidence_and_summaries(self, store_conn):
+        """Store with raw evidence and old summaries works correctly."""
+        # Set up store with mixed data
+        _open_period(store_conn, "2026-08-01T00:00:00+00:00")
+        
+        # Old day-only summary (legacy)
+        _insert_day_aggregate(store_conn, "2026-08-01", 
+                             bytes_written_delta=5000000)
+        
+        # Recent raw samples
+        _insert_sample(store_conn, "2026-09-14T10:00:00+00:00", 1000000)
+        _insert_sample(store_conn, "2026-09-14T10:30:00+00:00", 2000000)
+        
+        # Run repair
+        result = repair_derivation(store_conn)
+        assert result.ok is True
+        
+        # Verify legacy summary preserved
+        cursor = store_conn.execute(
+            "SELECT bytes_written_delta FROM day_aggregates WHERE day = '2026-08-01'"
+        )
+        assert cursor.fetchone()[0] == 5000000
+        
+        # Verify new hour observation created
+        cursor = store_conn.execute(
+            "SELECT COUNT(*) FROM hour_observations WHERE hour LIKE '2026-09-14%'"
+        )
+        assert cursor.fetchone()[0] == 1
+
+    def test_concurrent_reader_consistency(self, store_conn):
+        """Reader sees consistent snapshot during repair."""
+        # This is more of a documentation test - SQLite WAL mode handles this
+        # We verify the store is in WAL mode
+        cursor = store_conn.execute("PRAGMA journal_mode")
+        assert cursor.fetchone()[0] == "wal"

tests/test_segmentation.py

@@ -0,0 +1,465 @@
+"""Controller segmentation tests.
+
+Covers acceptance criteria:
+- ID-1: Identity key ladder, FR metadata only, independent axes
+- ID-2: Frozen metadata snapshot at segment open
+- ID-4: identity_degraded set exactly when key is blank
+- AC-4: vid/ssvid from PCI node, stored null otherwise
+- PR-16: Blank-key semantics (to/from blank quarantines, equal blanks continue)
+"""
+import sqlite3
+from datetime import datetime, timezone
+from pathlib import Path
+from typing import Any, Dict
+
+import pytest
+
+import sys
+sys.path.insert(0, str(Path(__file__).parent.parent / "src"))
+
+from fenris.store import init_store
+from fenris.collector import normalize_identity, compute_identity_degraded, acquire_from_sysfs
+from fenris.segment import find_current_segment, should_open_new_segment, open_segment
+
+
+# Fixtures
+
+@pytest.fixture
+def store(tmp_path: Path) -> sqlite3.Connection:
+    conn = init_store(tmp_path / "observations.db")
+    yield conn
+    conn.close()
+
+
+@pytest.fixture
+def clock():
+    class FakeClock:
+        def __init__(self):
+            self.now = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        def utcnow(self):
+            return self.now
+    return FakeClock()
+
+
+@pytest.fixture
+def identity_nqn() -> Dict[str, Any]:
+    return {
+        "subnqn": "nqn.2014-08.org.nvmexpress:uuid:12345678-1234-1234-1234-123456789abc",
+        "mn": "Samsung SSD 970 EVO Plus 1TB",
+        "sn": "S4EWNX0N123456",
+        "fr": "2B2QEXM7",
+        "vid": "0x144d",
+        "ssvid": "0x144d",
+        "transport": "pcie",
+    }
+
+
+@pytest.fixture
+def identity_model_serial() -> Dict[str, Any]:
+    return {
+        "subnqn": "",
+        "mn": "Samsung SSD 970 EVO Plus 1TB",
+        "sn": "S4EWNX0N123456",
+        "fr": "2B2QEXM7",
+        "vid": "0x144d",
+        "ssvid": "0x144d",
+        "transport": "pcie",
+    }
+
+
+@pytest.fixture
+def identity_degraded() -> Dict[str, Any]:
+    return {
+        "subnqn": "",
+        "mn": "",
+        "sn": "",
+        "fr": "2B2QEXM7",
+        "vid": "0x144d",
+        "ssvid": "0x144d",
+        "transport": "pcie",
+    }
+
+
+# ID-1: Identity key ladder
+
+class TestIdentityKeyLadder:
+    def test_subnqn_primary(self, identity_nqn):
+        key = normalize_identity(identity_nqn)
+        assert key == "nqn.2014-08.org.nvmexpress:uuid:12345678-1234-1234-1234-123456789abc"
+
+    def test_fallback_to_model_serial(self, identity_model_serial):
+        key = normalize_identity(identity_model_serial)
+        assert key == "Samsung SSD 970 EVO Plus 1TB|S4EWNX0N123456"
+
+    def test_all_blank_degraded(self, identity_degraded):
+        key = normalize_identity(identity_degraded)
+        assert key == ""
+
+    def test_firmware_is_metadata_only(self, identity_nqn):
+        key = normalize_identity(identity_nqn)
+        assert "2B2QEXM7" not in key
+
+
+# ID-2: Frozen metadata snapshot
+
+class TestFrozenMetadataSnapshot:
+    def test_segment_stores_all_metadata_fields(self, store, clock, identity_nqn):
+        key = normalize_identity(identity_nqn)
+        degraded = compute_identity_degraded(identity_nqn)
+        
+        segment = open_segment(store, clock.now, identity_nqn, key, degraded)
+        
+        assert segment["identity_key"] == key
+        assert segment["identity_degraded"] is False
+        assert segment["subnqn"] == identity_nqn["subnqn"]
+        assert segment["sn"] == identity_nqn["sn"]
+        assert segment["mn"] == identity_nqn["mn"]
+        assert segment["fr"] == identity_nqn["fr"]
+        assert segment["vid"] == identity_nqn["vid"]
+        assert segment["ssvid"] == identity_nqn["ssvid"]
+        assert segment["transport"] == identity_nqn["transport"]
+
+    def test_metadata_nullable(self, store, clock):
+        sparse_identity = {
+            "subnqn": "",
+            "mn": "Legacy Model",
+            "sn": "LEGACY123",
+            "fr": "1.0",
+            "vid": None,
+            "ssvid": None,
+            "transport": None,
+        }
+        
+        key = normalize_identity(sparse_identity)
+        degraded = compute_identity_degraded(sparse_identity)
+        segment = open_segment(store, clock.now, sparse_identity, key, degraded)
+        
+        assert segment["vid"] is None
+        assert segment["ssvid"] is None
+        assert segment["transport"] is None
+
+    def test_cntlid_excluded(self, store, clock, identity_nqn):
+        key = normalize_identity(identity_nqn)
+        degraded = compute_identity_degraded(identity_nqn)
+        
+        segment = open_segment(store, clock.now, identity_nqn, key, degraded)
+        
+        assert "cntlid" not in segment
+
+    def test_metadata_immutable_after_open(self, store, clock, identity_nqn):
+        key = normalize_identity(identity_nqn)
+        degraded = compute_identity_degraded(identity_nqn)
+        
+        open_segment(store, clock.now, identity_nqn, key, degraded)
+        
+        found = find_current_segment(store)
+        assert found["subnqn"] == identity_nqn["subnqn"]
+        assert found["vid"] == identity_nqn["vid"]
+        assert found["ssvid"] == identity_nqn["ssvid"]
+
+
+# ID-4: identity_degraded
+
+class TestIdentityDegraded:
+    def test_degraded_when_blank_key(self, store, clock, identity_degraded):
+        key = normalize_identity(identity_degraded)
+        degraded = compute_identity_degraded(identity_degraded)
+        
+        assert key == ""
+        assert degraded is True
+        
+        segment = open_segment(store, clock.now, identity_degraded, key, degraded)
+        assert segment["identity_degraded"] is True
+
+    def test_not_degraded_with_subnqn(self, store, clock, identity_nqn):
+        key = normalize_identity(identity_nqn)
+        degraded = compute_identity_degraded(identity_nqn)
+        
+        assert key != ""
+        assert degraded is False
+        
+        segment = open_segment(store, clock.now, identity_nqn, key, degraded)
+        assert segment["identity_degraded"] is False
+
+    def test_not_degraded_with_model_serial(self, store, clock, identity_model_serial):
+        key = normalize_identity(identity_model_serial)
+        degraded = compute_identity_degraded(identity_model_serial)
+        
+        assert key != ""
+        assert degraded is False
+        
+        segment = open_segment(store, clock.now, identity_model_serial, key, degraded)
+        assert segment["identity_degraded"] is False
+
+
+# AC-4: vid/ssvid from PCI node
+
+class TestVidSsvidAcquisition:
+    def test_vid_ssvid_from_pci_node(self, tmp_path: Path):
+        ctrl_dir = tmp_path / "nvme0"
+        ctrl_dir.mkdir()
+        
+        (ctrl_dir / "subsysnqn").write_text("nqn.test\n")
+        (ctrl_dir / "model").write_text("Test Model\n")
+        (ctrl_dir / "serial").write_text("TEST123\n")
+        (ctrl_dir / "firmware_rev").write_text("1.0\n")
+        (ctrl_dir / "vendor").write_text("0x144d\n")
+        (ctrl_dir / "subsystem_vendor").write_text("0x144d\n")
+        
+        identity = acquire_from_sysfs(ctrl_dir)
+        
+        assert identity["vid"] == "0x144d"
+        assert identity["ssvid"] == "0x144d"
+
+    def test_vid_ssvid_null_when_absent(self, tmp_path: Path):
+        ctrl_dir = tmp_path / "nvme0"
+        ctrl_dir.mkdir()
+        
+        (ctrl_dir / "subsysnqn").write_text("nqn.test\n")
+        (ctrl_dir / "model").write_text("Test Model\n")
+        (ctrl_dir / "serial").write_text("TEST123\n")
+        (ctrl_dir / "firmware_rev").write_text("1.0\n")
+        
+        identity = acquire_from_sysfs(ctrl_dir)
+        
+        assert identity["vid"] is None
+        assert identity["ssvid"] is None
+
+    def test_vid_ssvid_metadata_only(self, store, clock, identity_nqn):
+        identity_a = {**identity_nqn, "vid": "0x144d", "ssvid": "0x144d"}
+        identity_b = {**identity_nqn, "vid": "0xFFFF", "ssvid": "0xFFFF"}
+        
+        key_a = normalize_identity(identity_a)
+        key_b = normalize_identity(identity_b)
+        
+        assert key_a == key_b
+
+
+# PR-16: Blank-key semantics
+
+class TestBlankKeySemantics:
+    def test_to_blank_quarantines(self, store, clock):
+        healthy = {
+            "subnqn": "nqn.healthy",
+            "mn": "Model A", "sn": "SN1", "fr": "1.0",
+            "vid": "0x1", "ssvid": "0x1", "transport": "pcie",
+        }
+        key_healthy = normalize_identity(healthy)
+        degraded_healthy = compute_identity_degraded(healthy)
+        
+        open_segment(store, clock.now, healthy, key_healthy, degraded_healthy)
+        current = find_current_segment(store)
+        
+        blank = {
+            "subnqn": "", "mn": "", "sn": "",
+            "fr": "1.0", "vid": "0x1", "ssvid": "0x1", "transport": "pcie",
+        }
+        key_blank = normalize_identity(blank)
+        
+        should_open, reason = should_open_new_segment(
+            current, key_blank, 1000, store
+        )
+        
+        assert should_open is True
+        assert reason == "identity_change"
+
+    def test_from_blank_quarantines(self, store, clock):
+        blank = {
+            "subnqn": "", "mn": "", "sn": "",
+            "fr": "1.0", "vid": "0x1", "ssvid": "0x1", "transport": "pcie",
+        }
+        key_blank = normalize_identity(blank)
+        degraded_blank = compute_identity_degraded(blank)
+        
+        open_segment(store, clock.now, blank, key_blank, degraded_blank)
+        current = find_current_segment(store)
+        
+        healthy = {
+            "subnqn": "nqn.healthy",
+            "mn": "Model A", "sn": "SN1", "fr": "1.0",
+            "vid": "0x1", "ssvid": "0x1", "transport": "pcie",
+        }
+        key_healthy = normalize_identity(healthy)
+        
+        should_open, reason = should_open_new_segment(
+            current, key_healthy, 1000, store
+        )
+        
+        assert should_open is True
+        assert reason == "identity_change"
+
+    def test_equal_blanks_continue_by_duw(self, store, clock):
+        blank = {
+            "subnqn": "", "mn": "", "sn": "",
+            "fr": "1.0", "vid": "0x1", "ssvid": "0x1", "transport": "pcie",
+        }
+        key_blank = normalize_identity(blank)
+        degraded_blank = compute_identity_degraded(blank)
+        
+        open_segment(store, clock.now, blank, key_blank, degraded_blank)
+        current = find_current_segment(store)
+        
+        store.execute(
+            "INSERT INTO samples (ts, device, bytes_written) VALUES (?, ?, ?)",
+            ("2026-09-01T12:00:00Z", "/dev/nvme0", 1000)
+        )
+        store.commit()
+        
+        should_open, reason = should_open_new_segment(
+            current, key_blank, 2000, store
+        )
+        
+        assert should_open is False
+        assert reason is None
+
+    def test_equal_blanks_duw_decrease_opens(self, store, clock):
+        blank = {
+            "subnqn": "", "mn": "", "sn": "",
+            "fr": "1.0", "vid": "0x1", "ssvid": "0x1", "transport": "pcie",
+        }
+        key_blank = normalize_identity(blank)
+        degraded_blank = compute_identity_degraded(blank)
+        
+        open_segment(store, clock.now, blank, key_blank, degraded_blank)
+        current = find_current_segment(store)
+        
+        store.execute(
+            "INSERT INTO samples (ts, device, bytes_written) VALUES (?, ?, ?)",
+            ("2026-09-01T12:00:00Z", "/dev/nvme0", 2000)
+        )
+        store.commit()
+        
+        should_open, reason = should_open_new_segment(
+            current, key_blank, 1000, store
+        )
+        
+        assert should_open is True
+        assert reason == "duw_decrease"
+
+
+# Independent segmentation axes
+
+class TestIndependentAxes:
+    def test_identity_change_with_duw_increase(self, store, clock):
+        identity_a = {
+            "subnqn": "nqn.drive-a",
+            "mn": "Model A", "sn": "SN1", "fr": "1.0",
+            "vid": "0x1", "ssvid": "0x1", "transport": "pcie",
+        }
+        key_a = normalize_identity(identity_a)
+        degraded_a = compute_identity_degraded(identity_a)
+        
+        open_segment(store, clock.now, identity_a, key_a, degraded_a)
+        current = find_current_segment(store)
+        
+        store.execute(
+            "INSERT INTO samples (ts, device, bytes_written) VALUES (?, ?, ?)",
+            ("2026-09-01T12:00:00Z", "/dev/nvme0", 2000)
+        )
+        store.commit()
+        
+        identity_b = {
+            "subnqn": "nqn.drive-b",
+            "mn": "Model B", "sn": "SN2", "fr": "2.0",
+            "vid": "0x2", "ssvid": "0x2", "transport": "pcie",
+        }
+        key_b = normalize_identity(identity_b)
+        
+        should_open, reason = should_open_new_segment(
+            current, key_b, 3000, store
+        )
+        
+        assert should_open is True
+        assert reason == "identity_change"
+
+    def test_duw_decrease_same_identity(self, store, clock):
+        identity = {
+            "subnqn": "nqn.drive-a",
+            "mn": "Model A", "sn": "SN1", "fr": "1.0",
+            "vid": "0x1", "ssvid": "0x1", "transport": "pcie",
+        }
+        key = normalize_identity(identity)
+        degraded = compute_identity_degraded(identity)
+        
+        open_segment(store, clock.now, identity, key, degraded)
+        current = find_current_segment(store)
+        
+        store.execute(
+            "INSERT INTO samples (ts, device, bytes_written) VALUES (?, ?, ?)",
+            ("2026-09-01T12:00:00Z", "/dev/nvme0", 5000)
+        )
+        store.commit()
+        
+        should_open, reason = should_open_new_segment(
+            current, key, 3000, store
+        )
+        
+        assert should_open is True
+        assert reason == "duw_decrease"
+
+
+# Segment lifecycle
+
+class TestSegmentLifecycle:
+    def test_first_segment_always_opens(self, store):
+        key = "nqn.test"
+        
+        should_open, reason = should_open_new_segment(
+            None, key, 1000, store
+        )
+        
+        assert should_open is True
+        assert reason == "first_segment"
+
+    def test_same_identity_duw_non_decreasing_continues(self, store, clock):
+        identity = {
+            "subnqn": "nqn.drive",
+            "mn": "Model", "sn": "SN1", "fr": "1.0",
+            "vid": "0x1", "ssvid": "0x1", "transport": "pcie",
+        }
+        key = normalize_identity(identity)
+        degraded = compute_identity_degraded(identity)
+        
+        open_segment(store, clock.now, identity, key, degraded)
+        current = find_current_segment(store)
+        
+        store.execute(
+            "INSERT INTO samples (ts, device, bytes_written) VALUES (?, ?, ?)",
+            ("2026-09-01T12:00:00Z", "/dev/nvme0", 1000)
+        )
+        store.commit()
+        
+        should_open, reason = should_open_new_segment(
+            current, key, 1500, store
+        )
+        
+        assert should_open is False
+        assert reason is None
+
+    def test_multiple_segments(self, store, clock):
+        identity_a = {
+            "subnqn": "nqn.drive-a",
+            "mn": "Model A", "sn": "SN1", "fr": "1.0",
+            "vid": "0x1", "ssvid": "0x1", "transport": "pcie",
+        }
+        key_a = normalize_identity(identity_a)
+        degraded_a = compute_identity_degraded(identity_a)
+        
+        open_segment(store, clock.now, identity_a, key_a, degraded_a)
+        
+        identity_b = {
+            "subnqn": "nqn.drive-b",
+            "mn": "Model B", "sn": "SN2", "fr": "2.0",
+            "vid": "0x2", "ssvid": "0x2", "transport": "pcie",
+        }
+        key_b = normalize_identity(identity_b)
+        degraded_b = compute_identity_degraded(identity_b)
+        
+        open_segment(store, clock.now, identity_b, key_b, degraded_b)
+        
+        cursor = store.execute("SELECT COUNT(*) FROM controller_segments")
+        count = cursor.fetchone()[0]
+        assert count == 2
+        
+        current = find_current_segment(store)
+        assert current["identity_key"] == key_b

tests/test_signing.py

@@ -0,0 +1,480 @@
+"""Signing and consumer-repo structural tests (issue #51).
+
+Verifies that the signing infrastructure, consumer setup docs, and key
+publication are correctly wired — without requiring a real GPG key,
+network access, or Docker.
+
+All assertions are structural: config keys exist, URLs match, docs
+are present, and the Makefile exposes the right targets.  A throwaway
+test key exercise is included for rpm signature verification mechanics.
+"""
+import subprocess
+import tempfile
+from pathlib import Path
+
+import pytest
+
+REPO_ROOT = Path(__file__).resolve().parent.parent
+
+
+# ---------------------------------------------------------------------------
+# Helpers
+# ---------------------------------------------------------------------------
+
+def _read(path: str | Path) -> str:
+    from tests.conftest import read
+    return read(path)
+
+
+def _gpg_available() -> bool:
+    try:
+        r = subprocess.run(
+            ["gpg", "--version"], capture_output=True, timeout=5,
+        )
+        return r.returncode == 0
+    except (FileNotFoundError, subprocess.TimeoutExpired):
+        return False
+
+
+def _rpmsign_available() -> bool:
+    try:
+        r = subprocess.run(
+            ["rpmsign", "--version"], capture_output=True, timeout=5,
+        )
+        return r.returncode == 0
+    except (FileNotFoundError, subprocess.TimeoutExpired):
+        return False
+
+
+# ---------------------------------------------------------------------------
+# Tests — nfpm.yaml signing configuration
+# ---------------------------------------------------------------------------
+
+class TestNfpmSigningConfig:
+    """Verify that nfpm.yaml is correctly configured for RPM builds.
+
+    Note: RPM signing is done via rpmsign post-build (make sign-rpm),
+    not through nfpm's built-in signing. This keeps the build unsigned
+    and the signing step explicit and key-controlled.
+    """
+
+    def test_rpm_overrides_exist(self):
+        """nfpm.yaml must have overrides.rpm for per-format deltas."""
+        content = _read("packaging/nfpm.yaml")
+        assert "overrides:" in content, "overrides section missing from nfpm.yaml"
+        assert "rpm:" in content, "rpm overrides missing from nfpm.yaml"
+
+    def test_rpm_scripts_configured(self):
+        """RPM must use the dedicated scriptlets, not deb scripts."""
+        content = _read("packaging/nfpm.yaml")
+        assert "packaging/rpm/post.sh" in content, \
+            "RPM postinstall must use rpm/post.sh"
+        assert "packaging/rpm/preun.sh" in content, \
+            "RPM preremove must use rpm/preun.sh"
+        assert "packaging/rpm/postun.sh" in content, \
+            "RPM postremove must use rpm/postun.sh"
+
+    def test_rpm_depends_use_correct_syntax(self):
+        """RPM dependencies must use rpm-style version syntax."""
+        content = _read("packaging/nfpm.yaml")
+        assert "python3 >= 3.10" in content, \
+            "RPM depends must use rpm-style version constraint"
+
+
+# ---------------------------------------------------------------------------
+# Tests — Makefile signing targets
+# ---------------------------------------------------------------------------
+
+class TestMakefileSigningTargets:
+    """Verify that the Makefile exposes signing-related targets."""
+
+    def _makefile_content(self) -> str:
+        return _read("Makefile")
+
+    def test_generate_test_key_target(self):
+        content = self._makefile_content()
+        assert "generate-test-key:" in content, \
+            "Makefile must have a generate-test-key target"
+        assert "packaging-test@bongbetic.com" in content or \
+               "packaging@bongbetic.com" in content, \
+            "generate-test-key must reference the packaging key UID"
+
+    def test_sign_rpm_target(self):
+        content = self._makefile_content()
+        assert "sign-rpm:" in content, \
+            "Makefile must have a sign-rpm target"
+        assert "rpmsign" in content, \
+            "sign-rpm target must use rpmsign"
+
+    def test_checksums_target(self):
+        content = self._makefile_content()
+        assert "checksums:" in content, \
+            "Makefile must have a checksums target"
+        assert "sha256sum" in content, \
+            "checksums target must use sha256sum"
+
+    def test_clearsign_target(self):
+        content = self._makefile_content()
+        assert "clearsign:" in content, \
+            "Makefile must have a clearsign target"
+        assert "--clearsign" in content, \
+            "clearsign target must use gpg --clearsign"
+
+    def test_release_depends_on_signing(self):
+        content = self._makefile_content()
+        for line in content.splitlines():
+            if line.startswith("release:"):
+                deps = line.split(":", 1)[1].strip()
+                assert "sign-rpm" in deps, \
+                    "release target must depend on sign-rpm"
+                assert "clearsign" in deps, \
+                    "release target must depend on clearsign"
+                break
+        else:
+            pytest.fail("release target not found in Makefile")
+
+    def test_packaging_key_uid_defined(self):
+        content = self._makefile_content()
+        assert "PACKAGING_KEY" in content, \
+            "Makefile must define PACKAGING_KEY variable"
+
+    def test_release_mentions_key_ceremony(self):
+        content = self._makefile_content()
+        assert "signing-key-ceremony.md" in content, \
+            "release target must reference the key ceremony doc"
+
+
+# ---------------------------------------------------------------------------
+# Tests — fenris.repo configuration
+# ---------------------------------------------------------------------------
+
+class TestFenrisRepo:
+    """Verify the dnf repo file is correctly configured for Fenris."""
+
+    def _repo_content(self) -> str:
+        return _read("packaging/fenris.repo")
+
+    def test_gpgcheck_enabled(self):
+        content = self._repo_content()
+        assert "gpgcheck=1" in content, \
+            "fenris.repo must set gpgcheck=1 for payload verification"
+
+    def test_repo_gpgcheck_disabled(self):
+        content = self._repo_content()
+        assert "repo_gpgcheck=0" in content, \
+            "fenris.repo must set repo_gpgcheck=0 (metadata check via TLS)"
+
+    def test_gpgkey_points_to_packaging_key(self):
+        content = self._repo_content()
+        assert "gpgkey=" in content, \
+            "fenris.repo must have a gpgkey directive"
+        assert "fenris-packaging.asc" in content, \
+            "gpgkey must point at the packaging key"
+        assert "raw/branch/main" in content, \
+            "gpgkey must use raw URL for the public key"
+
+    def test_baseurl_is_fenris_rpm_group(self):
+        content = self._repo_content()
+        assert "rpm/fenris" in content, \
+            "baseurl must point at the fenris RPM group"
+
+
+# ---------------------------------------------------------------------------
+# Tests — public key publication
+# ---------------------------------------------------------------------------
+
+class TestKeyPublication:
+    """Verify the public key is published in-repo with correct metadata."""
+
+    def test_key_file_exists(self):
+        key_path = REPO_ROOT / "packaging" / "keys" / "fenris-packaging.asc"
+        assert key_path.exists(), \
+            "packaging/keys/fenris-packaging.asc must exist"
+
+    def test_key_file_has_raw_url(self):
+        content = _read("packaging/keys/fenris-packaging.asc")
+        raw_url = (
+            "https://git.bongbetic.com/xavierk/Fenris/raw/branch/main/"
+            "packaging/keys/fenris-packaging.asc"
+        )
+        assert raw_url in content, \
+            "Key file must contain its own raw URL as documentation"
+
+    def test_key_file_documents_algorithm(self):
+        content = _read("packaging/keys/fenris-packaging.asc")
+        assert "RSA 3072" in content or "rsa3072" in content.lower(), \
+            "Key file must document the algorithm as RSA 3072"
+
+    def test_key_file_documents_uid(self):
+        content = _read("packaging/keys/fenris-packaging.asc")
+        assert "Fenris Packaging" in content, \
+            "Key file must document the UID"
+
+    def test_key_file_documents_expiry(self):
+        content = _read("packaging/keys/fenris-packaging.asc")
+        assert "2 year" in content or "2-year" in content or "expiry" in content.lower(), \
+            "Key file must document the expiry policy"
+
+    def test_key_file_references_ceremony_doc(self):
+        content = _read("packaging/keys/fenris-packaging.asc")
+        assert "signing-key-ceremony.md" in content, \
+            "Key file must reference the key ceremony document"
+
+
+# ---------------------------------------------------------------------------
+# Tests — key ceremony documentation
+# ---------------------------------------------------------------------------
+
+class TestKeyCeremonyDoc:
+    """Verify the key ceremony document is complete and accurate."""
+
+    def _doc_content(self) -> str:
+        return _read("docs/install/signing-key-ceremony.md")
+
+    def test_ceremony_doc_exists(self):
+        assert (REPO_ROOT / "docs" / "install" / "signing-key-ceremony.md").exists(), \
+            "docs/install/signing-key-ceremony.md must exist"
+
+    def test_documents_key_specification(self):
+        content = self._doc_content()
+        assert "RSA 3072" in content, "Must document RSA 3072 algorithm"
+        assert "Fenris Packaging" in content, "Must document the UID"
+        assert "packaging@bongbetic.com" in content, "Must document the email"
+
+    def test_documents_import_sign_delete(self):
+        content = self._doc_content()
+        assert "import" in content.lower(), "Must document import step"
+        assert "sign" in content.lower(), "Must document sign step"
+        assert "delete" in content.lower(), "Must document delete step"
+
+    def test_documents_rotation_outline(self):
+        content = self._doc_content()
+        assert "rotation" in content.lower(), \
+            "Must document key rotation procedure"
+
+    def test_documents_dual_key_approach(self):
+        content = self._doc_content()
+        assert "previous" in content.lower() or "old" in content.lower(), \
+            "Must document old key retention during rotation"
+
+    def test_documents_private_key_storage(self):
+        content = self._doc_content()
+        assert "password manager" in content.lower(), \
+            "Must document that private key lives in password manager"
+
+
+# ---------------------------------------------------------------------------
+# Tests — consumer setup documentation
+# ---------------------------------------------------------------------------
+
+class TestConsumerDocs:
+    """Verify consumer setup docs are present and correctly wired."""
+
+    def _readme_content(self) -> str:
+        return _read("README.md")
+
+    def test_apt_signed_by_flow(self):
+        content = self._readme_content()
+        assert "signed-by" in content, \
+            "README must document apt signed-by keyring flow"
+        assert "keyrings" in content, \
+            "README must show the keyrings directory"
+
+    def test_apt_fingerprint_placeholder(self):
+        content = self._readme_content()
+        assert "Fingerprint" in content or "fingerprint" in content, \
+            "README must include fingerprint placeholder for TOFU hardening"
+
+    def test_dnf_repo_flow(self):
+        content = self._readme_content()
+        assert "dnf config-manager --add-repo" in content or \
+               "dnf install" in content, \
+            "README must document dnf install flow"
+        assert "fenris.repo" in content, \
+            "README must reference the Fenris-owned repo file"
+
+    def test_no_gitea_auto_repo(self):
+        """Gitea's auto-generated .repo must never be referenced in docs."""
+        content = self._readme_content()
+        # The Gitea auto-generated repo would have gpgcheck=1 against the
+        # instance key, which is a trap. Our docs should only reference
+        # our own fenris.repo file.
+        assert "auto-generated" not in content.lower() or \
+               "never" in content.lower(), \
+            "README must not recommend Gitea's auto-generated .repo"
+
+    def test_package_signature_verification(self):
+        content = self._readme_content()
+        assert "rpm -K" in content or "rpm --checksig" in content, \
+            "README must document RPM signature verification"
+        assert "gpg --verify" in content, \
+            "README must document GPG verification for SHA256SUMS"
+
+    def test_migration_from_make_install(self):
+        content = self._readme_content()
+        assert "migrate-from-makeinstall" in content.lower() or \
+               "migration" in content.lower(), \
+            "README must reference the migration runbook"
+
+
+# ---------------------------------------------------------------------------
+# Tests — release spec references
+# ---------------------------------------------------------------------------
+
+class TestReleaseSpecReferences:
+    """Verify the release spec references the ceremony doc and nfpm config."""
+
+    def _spec_content(self) -> str:
+        return _read("docs/spec/release-packaging.md")
+
+    def test_spec_references_rpmsign(self):
+        content = self._spec_content()
+        assert "rpmsign" in content.lower() or "sign-rpm" in content, \
+            "Spec must reference rpmsign or make sign-rpm for RPM signing"
+
+    def test_spec_references_ceremony_doc(self):
+        content = self._spec_content()
+        assert "signing-key-ceremony.md" in content, \
+            "Spec must reference the key ceremony document"
+
+
+# ---------------------------------------------------------------------------
+# Tests — RPM signature mechanics (throwaway test key, no network)
+# ---------------------------------------------------------------------------
+
+class TestRpmSignatureMechanics:
+    """Verify RPM signing mechanics using a throwaway test key.
+
+    These tests generate a temporary GPG key, build an RPM (or use an
+    existing one), sign it, and verify the signature — all without
+    network access.  They require gpg and rpmsign to be available.
+    """
+
+    @pytest.mark.skipif(
+        not _gpg_available() or not _rpmsign_available(),
+        reason="gpg or rpmsign not available",
+    )
+    def test_throwaway_key_signs_and_verifies(self):
+        """Generate a throwaway key, sign a test RPM, verify signature."""
+        # Find existing RPM
+        version = None
+        for line in (REPO_ROOT / "pyproject.toml").read_text().splitlines():
+            if line.startswith("version"):
+                version = line.split("=")[1].strip().strip('"')
+                break
+        rpm_path = REPO_ROOT / "dist" / f"fenris-{version}-1.x86_64.rpm"
+        if not rpm_path.exists():
+            pytest.skip("RPM not built — run `make package-rpm` first")
+
+        key_uid = "fenris-test-signing@example.com"
+        try:
+            # Generate throwaway key
+            subprocess.run(
+                ["gpg", "--batch", "--gen-key"],
+                input=f"""%no-protection
+Key-Type: RSA
+Key-Length: 3072
+Name-Real: {key_uid}
+Name-Email: {key_uid}
+Expire-Date: 0
+%commit
+""",
+                text=True, check=True, timeout=30,
+            )
+
+            # Copy RPM to temp dir for signing
+            with tempfile.TemporaryDirectory() as tmpdir:
+                signed_rpm = Path(tmpdir) / rpm_path.name
+                signed_rpm.write_bytes(rpm_path.read_bytes())
+
+                # Sign the RPM
+                subprocess.run(
+                    ["rpmsign", "--addsign",
+                     "--define", f"_gpg_name {key_uid}",
+                     str(signed_rpm)],
+                    check=True, timeout=30,
+                )
+
+                # Verify the signature exists and has correct format
+                # (rpm -Kv returns NOKEY if key isn't imported, but the
+                # signature header is still present and verifiable)
+                r = subprocess.run(
+                    ["rpm", "-Kv", str(signed_rpm)],
+                    capture_output=True, text=True, timeout=10,
+                )
+                output = r.stdout + r.stderr
+                assert "RSA" in output or "rsa" in output.lower(), \
+                    f"RPM must have RSA signature: {output}"
+                assert "SHA256" in output or "sha256" in output.lower(), \
+                    f"RPM must have SHA256 digest: {output}"
+                assert "Header V4" in output or "Header" in output, \
+                    f"RPM must have V4 signature header: {output}"
+                assert "Signature" in output, \
+                    f"RPM must show signature info: {output}"
+
+        finally:
+            # Clean up the test key
+            subprocess.run(
+                ["gpg", "--batch", "--yes", "--delete-secret-keys", key_uid],
+                capture_output=True, timeout=5,
+            )
+            subprocess.run(
+                ["gpg", "--batch", "--yes", "--delete-keys", key_uid],
+                capture_output=True, timeout=5,
+            )
+
+    @pytest.mark.skipif(
+        not _gpg_available(),
+        reason="gpg not available",
+    )
+    def test_clearsign_and_verify(self):
+        """Clearsign a test manifest and verify the signature."""
+        key_uid = "fenris-test-clearsign@example.com"
+        try:
+            # Generate throwaway key
+            subprocess.run(
+                ["gpg", "--batch", "--gen-key"],
+                input=f"""%no-protection
+Key-Type: RSA
+Key-Length: 3072
+Name-Real: {key_uid}
+Name-Email: {key_uid}
+Expire-Date: 0
+%commit
+""",
+                text=True, check=True, timeout=30,
+            )
+
+            with tempfile.TemporaryDirectory() as tmpdir:
+                sums = Path(tmpdir) / "SHA256SUMS"
+                sums.write_text(
+                    "abc123  fenris_0.3.0_amd64.deb\n"
+                    "def456  fenris-0.3.0-1.x86_64.rpm\n"
+                )
+
+                # Clearsign
+                subprocess.run(
+                    ["gpg", "--batch", "--yes", "--clearsign",
+                     "--local-user", key_uid, str(sums)],
+                    check=True, timeout=10,
+                )
+
+                # Verify (clearsigned file — just one argument to --verify)
+                r = subprocess.run(
+                    ["gpg", "--verify", str(sums.with_suffix(".asc"))],
+                    capture_output=True, text=True, timeout=10,
+                )
+                assert r.returncode == 0, \
+                    f"Clearsign verification failed: {r.stderr}"
+                assert "Good signature" in r.stderr, \
+                    f"Expected Good signature: {r.stderr}"
+
+        finally:
+            subprocess.run(
+                ["gpg", "--batch", "--yes", "--delete-secret-keys", key_uid],
+                capture_output=True, timeout=5,
+            )
+            subprocess.run(
+                ["gpg", "--batch", "--yes", "--delete-keys", key_uid],
+                capture_output=True, timeout=5,
+            )

tests/test_status.py

@@ -0,0 +1,687 @@
+"""Tests for the read-only CLI status command (issue #27).
+
+Covers:
+  - LC-9: status is a pure read-only composition
+  - CI-2: TUI/CLI parity (status fact set matches TUI's four separate facts)
+  - CI-4: Required wording and six disclosures render as adopted
+  - FL-4: Store fault renders exact fixed phrase
+  - FL-5: Newer-schema store renders exact fixed phrase
+  - FL-7: Drive anomalies render as ordinary facts, never affecting projection
+  - LC-10: Freshness grading with shared constants
+  - Retired command rejection with migration pointers
+  - Configuration error surfaced from direct reads
+"""
+import os
+import sqlite3
+import sys
+import tempfile
+from datetime import datetime, timedelta, timezone
+from pathlib import Path
+from unittest.mock import patch, MagicMock
+
+import pytest
+
+sys.path.insert(0, str(Path(__file__).parent.parent / "src"))
+
+from fenris.status import (
+    grade_freshness,
+    freshness_age_human,
+    format_disclosures,
+    check_retired_command,
+    check_retired_flag,
+    FRESH_THRESHOLD_S,
+    STALENESS_THRESHOLD_S,
+    CADENCE_DEFAULT_S,
+    ACCURACY_SEC,
+)
+from fenris.store import init_store, SCHEMA_VERSION
+from fenris.projection import DISCLOSURES, ConfidenceState
+
+
+# ---------------------------------------------------------------------------
+# Freshness grading (§8.9, LC-10)
+# ---------------------------------------------------------------------------
+
+class TestFreshnessGrading:
+    """Freshness constants are defined once and shared (§8.9)."""
+
+    def test_constants_match_spec(self):
+        """Fresh threshold = 2 × cadence + AccuracySec + 60 s."""
+        expected = 2 * CADENCE_DEFAULT_S + ACCURACY_SEC + 60
+        assert FRESH_THRESHOLD_S == expected
+        assert STALENESS_THRESHOLD_S == 48 * 3600
+
+    def test_empty_store(self):
+        """Empty store reads 'no observations yet' (§8.9)."""
+        now = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        assert grade_freshness(None, now) == "empty"
+
+    def test_fresh_sample(self):
+        """Newest sample within threshold → fresh."""
+        now = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        ts = (now - timedelta(seconds=FRESH_THRESHOLD_S - 1)).isoformat()
+        assert grade_freshness(ts, now) == "fresh"
+
+    def test_missed_sample(self):
+        """Between fresh and 48h → missed."""
+        now = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        ts = (now - timedelta(hours=2)).isoformat()
+        assert grade_freshness(ts, now) == "missed"
+
+    def test_stale_sample(self):
+        """≥ 48h → stale."""
+        now = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        ts = (now - timedelta(hours=49)).isoformat()
+        assert grade_freshness(ts, now) == "stale"
+
+    def test_fresh_at_boundary(self):
+        """Exactly at threshold → fresh (within means ≤)."""
+        now = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        ts = (now - timedelta(seconds=FRESH_THRESHOLD_S)).isoformat()
+        assert grade_freshness(ts, now) == "fresh"
+
+    def test_missed_at_just_past_fresh(self):
+        """One second past threshold → missed."""
+        now = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        ts = (now - timedelta(seconds=FRESH_THRESHOLD_S + 1)).isoformat()
+        assert grade_freshness(ts, now) == "missed"
+
+    def test_stale_at_boundary(self):
+        """Exactly 48h → stale."""
+        now = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        ts = (now - timedelta(hours=48)).isoformat()
+        assert grade_freshness(ts, now) == "stale"
+
+    def test_naive_timestamp_treated_as_utc(self):
+        """Naive timestamp is treated as UTC — within fresh threshold."""
+        now = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        # Construct a truly naive ISO string (no +00:00 suffix), 5 min ago
+        naive_dt = datetime(2026, 9, 1, 11, 55, 0)  # 5 min ago, naive
+        ts = naive_dt.isoformat()  # "2026-09-01T11:55:00"
+        assert grade_freshness(ts, now) == "fresh"
+
+    def test_malformed_timestamp_returns_empty(self):
+        """Malformed timestamp → empty."""
+        now = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        assert grade_freshness("not-a-timestamp", now) == "empty"
+
+
+# ---------------------------------------------------------------------------
+# Freshness age human-readable
+# ---------------------------------------------------------------------------
+
+class TestFreshnessAgeHuman:
+    def test_seconds(self):
+        assert freshness_age_human(30) == "30s ago"
+
+    def test_minutes(self):
+        assert freshness_age_human(120) == "2m ago"
+
+    def test_hours_and_minutes(self):
+        assert freshness_age_human(3661) == "1h 1m ago"
+
+    def test_days(self):
+        assert freshness_age_human(90000) == "1d ago"
+
+    def test_none(self):
+        assert freshness_age_human(None) == "unknown age"
+
+
+# ---------------------------------------------------------------------------
+# Retired command rejection (§8.8)
+# ---------------------------------------------------------------------------
+
+class TestRetiredCommands:
+    """Retired commands and --device are rejected with one-line pointers."""
+
+    def test_start_rejected(self):
+        ptr = check_retired_command("start")
+        assert ptr is not None
+        assert "resume" in ptr.lower() or "enable" in ptr.lower()
+
+    def test_stop_rejected(self):
+        ptr = check_retired_command("stop")
+        assert ptr is not None
+        assert "pause" in ptr.lower() or "disable" in ptr.lower()
+
+    def test_run_rejected(self):
+        ptr = check_retired_command("run")
+        assert ptr is not None
+
+    def test_status_not_rejected(self):
+        assert check_retired_command("status") is None
+
+    def test_sample_not_rejected(self):
+        assert check_retired_command("sample") is None
+
+    def test_device_flag_rejected(self):
+        ptr = check_retired_flag("--device")
+        assert ptr is not None
+        assert "fenris.conf" in ptr
+
+    def test_unknown_flag_not_rejected(self):
+        assert check_retired_flag("--unknown") is None
+
+
+# ---------------------------------------------------------------------------
+# Disclosures (§6.11, CI-4)
+# ---------------------------------------------------------------------------
+
+class TestDisclosures:
+    """Required wording and six disclosures render as adopted (CI-4)."""
+
+    def test_six_disclosures(self):
+        assert len(DISCLOSURES) == 6
+
+    def test_disclosures_text(self):
+        """Each disclosure matches the spec verbatim."""
+        assert "endurance projection" in DISCLOSURES[0].lower()
+        assert "hardware-failure" in DISCLOSURES[0].lower() or "failure date" in DISCLOSURES[0].lower()
+        assert "vendor-specific" in DISCLOSURES[1]
+        assert "255 is saturated" in DISCLOSURES[1]
+        assert "warranty" in DISCLOSURES[2] or "endurance threshold" in DISCLOSURES[2]
+        assert "DUW" in DISCLOSURES[3]
+        assert "metadata" in DISCLOSURES[3]
+        assert "future workload" in DISCLOSURES[4]
+        assert "deliberately disabled" in DISCLOSURES[5]
+
+    def test_format_disclosures_returns_all_six(self):
+        output = format_disclosures()
+        for i in range(1, 7):
+            assert "%d." % i in output
+
+    def test_disclosures_header(self):
+        output = format_disclosures()
+        assert output.startswith("Disclosures")
+
+
+# ---------------------------------------------------------------------------
+# Store fault rendering (§9.4, FL-4)
+# ---------------------------------------------------------------------------
+
+class TestStoreFault:
+    """Store fault surfaces exact fixed phrase (FL-4)."""
+
+    def test_store_fault_phrase(self, tmp_path):
+        """observation store unreadable with journal hint."""
+        from fenris.status import open_store_readonly, StoreFault
+
+        nonexistent = tmp_path / "nonexistent.db"
+        with pytest.raises(StoreFault):
+            open_store_readonly(nonexistent)
+
+    def test_corrupt_store(self, tmp_path):
+        """Corrupt file raises StoreFault."""
+        from fenris.status import open_store_readonly, StoreFault
+
+        corrupt = tmp_path / "corrupt.db"
+        corrupt.write_bytes(b"this is not a sqlite database")
+        with pytest.raises(StoreFault):
+            open_store_readonly(corrupt)
+
+
+# ---------------------------------------------------------------------------
+# Newer schema rendering (§9.5, FL-5)
+# ---------------------------------------------------------------------------
+
+class TestNewerSchema:
+    """Newer-schema store renders exact fixed phrase (FL-5)."""
+
+    def test_newer_schema_detected(self, tmp_path):
+        from fenris.status import open_store_readonly, NewerSchema
+
+        db = tmp_path / "test.db"
+        conn = sqlite3.connect(str(db))
+        conn.execute("PRAGMA user_version=%d" % (SCHEMA_VERSION + 1))
+        conn.commit()
+        conn.close()
+
+        with pytest.raises(NewerSchema):
+            open_store_readonly(db)
+
+
+# ---------------------------------------------------------------------------
+# Configuration error (§8.3, LC-4)
+# ---------------------------------------------------------------------------
+
+class TestConfigError:
+    """Configuration error surfaced as configuration error: <reason>."""
+
+    def test_missing_config(self):
+        from fenris.status import read_config, ConfigError
+        with patch("fenris.status.CONFIG_PATH", Path("/nonexistent/fenris.conf")):
+            with pytest.raises(ConfigError, match="not found"):
+                read_config()
+
+    def test_empty_config(self, tmp_path):
+        from fenris.status import read_config, ConfigError
+        conf = tmp_path / "fenris.conf"
+        conf.write_text("# empty config\n")
+        with patch("fenris.status.CONFIG_PATH", conf):
+            with pytest.raises(ConfigError, match="no device selector"):
+                read_config()
+
+    def test_valid_config(self, tmp_path):
+        from fenris.status import read_config
+        conf = tmp_path / "fenris.conf"
+        conf.write_text("device = /dev/disk/by-id/nvme-test\n")
+        with patch("fenris.status.CONFIG_PATH", conf):
+            result = read_config()
+            assert result["device"] == "/dev/disk/by-id/nvme-test"
+
+
+# ---------------------------------------------------------------------------
+# Drive anomalies (§9.7, FL-7)
+# ---------------------------------------------------------------------------
+
+class TestDriveAnomalies:
+    """Drive anomalies render as ordinary facts, never affecting projection."""
+
+    def test_no_anomalies(self, tmp_path):
+        from fenris.status import _query_drive_facts
+
+        db = tmp_path / "test.db"
+        conn = init_store(db)
+        conn.execute(
+            "INSERT INTO samples (ts, device, mn, sn, fr, capacity_bytes, "
+            "percentage_used, available_spare, media_errors, power_on_hours, "
+            "power_cycles, unsafe_shutdowns, temperature_c, "
+            "data_units_written, data_units_read, bytes_written, bytes_read, "
+            "critical_warning) "
+            "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)",
+            ("2026-09-01T12:00:00Z", "/dev/nvme0", "Test", "SN", "FR",
+             1000000000000, 5, 100, 0, 1000, 100, 0, 35,
+             1000000, 500000, 512000000000, 256000000000, 0),
+        )
+        conn.commit()
+        facts = _query_drive_facts(conn)
+        assert facts == []
+        conn.close()
+
+    def test_critical_warning(self, tmp_path):
+        from fenris.status import _query_drive_facts
+
+        db = tmp_path / "test.db"
+        conn = init_store(db)
+        conn.execute(
+            "INSERT INTO samples (ts, device, mn, sn, fr, capacity_bytes, "
+            "percentage_used, available_spare, media_errors, power_on_hours, "
+            "power_cycles, unsafe_shutdowns, temperature_c, "
+            "data_units_written, data_units_read, bytes_written, bytes_read, "
+            "critical_warning) "
+            "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)",
+            ("2026-09-01T12:00:00Z", "/dev/nvme0", "Test", "SN", "FR",
+             1000000000000, 5, 100, 0, 1000, 100, 0, 35,
+             1000000, 500000, 512000000000, 256000000000, 1),
+        )
+        conn.commit()
+        facts = _query_drive_facts(conn)
+        assert any("critical warning" in f for f in facts)
+        conn.close()
+
+    def test_media_errors(self, tmp_path):
+        from fenris.status import _query_drive_facts
+
+        db = tmp_path / "test.db"
+        conn = init_store(db)
+        conn.execute(
+            "INSERT INTO samples (ts, device, mn, sn, fr, capacity_bytes, "
+            "percentage_used, available_spare, media_errors, power_on_hours, "
+            "power_cycles, unsafe_shutdowns, temperature_c, "
+            "data_units_written, data_units_read, bytes_written, bytes_read, "
+            "critical_warning) "
+            "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)",
+            ("2026-09-01T12:00:00Z", "/dev/nvme0", "Test", "SN", "FR",
+             1000000000000, 5, 100, 3, 1000, 100, 0, 35,
+             1000000, 500000, 512000000000, 256000000000, 0),
+        )
+        conn.commit()
+        facts = _query_drive_facts(conn)
+        assert any("media errors" in f for f in facts)
+        conn.close()
+
+    def test_unsafe_shutdowns(self, tmp_path):
+        from fenris.status import _query_drive_facts
+
+        db = tmp_path / "test.db"
+        conn = init_store(db)
+        conn.execute(
+            "INSERT INTO samples (ts, device, mn, sn, fr, capacity_bytes, "
+            "percentage_used, available_spare, media_errors, power_on_hours, "
+            "power_cycles, unsafe_shutdowns, temperature_c, "
+            "data_units_written, data_units_read, bytes_written, bytes_read, "
+            "critical_warning) "
+            "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)",
+            ("2026-09-01T12:00:00Z", "/dev/nvme0", "Test", "SN", "FR",
+             1000000000000, 5, 100, 0, 1000, 100, 5, 35,
+             1000000, 500000, 512000000000, 256000000000, 0),
+        )
+        conn.commit()
+        facts = _query_drive_facts(conn)
+        assert any("unsafe shutdowns" in f for f in facts)
+        conn.close()
+
+
+# ---------------------------------------------------------------------------
+# Empty store greeting (§8.9, LC-10)
+# ---------------------------------------------------------------------------
+
+class TestEmptyStoreGreeting:
+    """Empty store reads 'no observations yet' with enable hint."""
+
+    def test_empty_store_message(self, tmp_path):
+        from fenris.status import get_status
+
+        db = tmp_path / "observations.db"
+        init_store(db)
+        now = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+
+        with patch("fenris.status.query_service_state", return_value={
+            "boot_enabled": False, "timer_active": False,
+            "last_collect_ok": None, "last_collect_age_s": None,
+            "last_collect_reason": None,
+        }):
+            result = get_status(store_path=db, clock_now=now,
+                                query_services=True, query_journal=False)
+
+        assert "no observations yet" in result
+        assert "enable" in result.lower() or "resume" in result.lower()
+
+
+# ---------------------------------------------------------------------------
+# Four separate service facts (§7.3, LC-9, CI-2)
+# ---------------------------------------------------------------------------
+
+class TestServiceFacts:
+    """Status renders four separate service facts matching TUI (CI-2)."""
+
+    def test_service_facts_present(self, tmp_path):
+        from fenris.status import get_status
+
+        db = tmp_path / "observations.db"
+        init_store(db)
+        now = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+
+        with patch("fenris.status.query_service_state", return_value={
+            "boot_enabled": True, "timer_active": True,
+            "last_collect_ok": True, "last_collect_age_s": 120,
+            "last_collect_reason": None,
+        }):
+            result = get_status(store_path=db, clock_now=now,
+                                query_services=True, query_journal=False)
+
+        assert "boot:" in result
+        assert "timer:" in result
+        assert "last collect:" in result
+        assert "freshness:" in result
+
+    def test_continuity_reports_boot_enabled_independently_of_runtime(self, tmp_path):
+        """Status names reboot continuity while retaining the timer fact."""
+        from fenris.status import get_status
+
+        db = tmp_path / "observations.db"
+        init_store(db)
+        now = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+
+        with patch("fenris.status.query_service_state", return_value={
+            "boot_enabled": True, "timer_active": False,
+            "last_collect_ok": None, "last_collect_age_s": None,
+            "last_collect_reason": None,
+        }):
+            result = get_status(store_path=db, clock_now=now,
+                                query_services=True, query_journal=False)
+
+        assert "monitoring: active in background · persists across reboots" in result
+        assert "timer: inactive" in result
+
+    def test_continuity_and_deliberate_pause_are_reported_separately(self, tmp_path):
+        """Only a sanctioned user_disabled period renders the paused wording."""
+        from fenris.status import get_status
+
+        db = tmp_path / "observations.db"
+        conn = init_store(db)
+        conn.execute(
+            "INSERT INTO monitoring_periods (started_at, ended_at, end_cause) "
+            "VALUES (?, ?, ?)",
+            ("2026-09-01T09:00:00+00:00", "2026-09-01T10:00:00+00:00", "user_disabled"),
+        )
+        conn.commit()
+        conn.close()
+        now = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+
+        with patch("fenris.status.query_service_state", return_value={
+            "boot_enabled": False, "timer_active": False,
+            "last_collect_ok": None, "last_collect_age_s": None,
+            "last_collect_reason": None,
+        }):
+            result = get_status(store_path=db, clock_now=now,
+                                query_services=True, query_journal=False)
+
+        assert "monitoring: does not start on next boot" in result
+        assert "monitoring: paused — deliberate disable" in result
+        assert "paused time is excluded from your usage habit · resume: fenris monitor resume" in result
+
+    def test_raw_system_state_without_user_disabled_is_not_a_deliberate_pause(self, tmp_path):
+        """A non-sanctioned stop never acquires the deliberate-disable label."""
+        from fenris.status import get_status
+
+        db = tmp_path / "observations.db"
+        conn = init_store(db)
+        conn.execute(
+            "INSERT INTO monitoring_periods (started_at, ended_at, end_cause) "
+            "VALUES (?, ?, ?)",
+            ("2026-09-01T09:00:00+00:00", "2026-09-01T10:00:00+00:00", "migrated"),
+        )
+        conn.commit()
+        conn.close()
+        now = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+
+        with patch("fenris.status.query_service_state", return_value={
+            "boot_enabled": False, "timer_active": False,
+            "last_collect_ok": None, "last_collect_age_s": None,
+            "last_collect_reason": None,
+        }):
+            result = get_status(store_path=db, clock_now=now,
+                                query_services=True, query_journal=False)
+
+        assert "monitoring: paused — deliberate disable" not in result
+
+    def test_resumed_open_period_clears_a_previous_deliberate_pause(self, tmp_path):
+        """A later sanctioned resume takes precedence over an older pause."""
+        from fenris.status import get_status
+
+        db = tmp_path / "observations.db"
+        conn = init_store(db)
+        conn.execute(
+            "INSERT INTO monitoring_periods (started_at, ended_at, end_cause) "
+            "VALUES (?, ?, ?)",
+            ("2026-09-01T09:00:00+00:00", "2026-09-01T10:00:00+00:00", "user_disabled"),
+        )
+        conn.execute(
+            "INSERT INTO monitoring_periods (started_at) VALUES (?)",
+            ("2026-09-01T11:00:00+00:00",),
+        )
+        conn.commit()
+        conn.close()
+        now = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+
+        with patch("fenris.status.query_service_state", return_value={
+            "boot_enabled": True, "timer_active": True,
+            "last_collect_ok": None, "last_collect_age_s": None,
+            "last_collect_reason": None,
+        }):
+            result = get_status(store_path=db, clock_now=now,
+                                query_services=True, query_journal=False)
+
+        assert "monitoring: paused — deliberate disable" not in result
+
+    def test_live_enabled_service_suppresses_a_stale_pause_marker(self, tmp_path):
+        """A raw re-enable cannot leave a contradictory paused presentation."""
+        from fenris.status import get_status
+
+        db = tmp_path / "observations.db"
+        conn = init_store(db)
+        conn.execute(
+            "INSERT INTO monitoring_periods (started_at, ended_at, end_cause) "
+            "VALUES (?, ?, ?)",
+            ("2026-09-01T09:00:00+00:00", "2026-09-01T10:00:00+00:00", "user_disabled"),
+        )
+        conn.commit()
+        conn.close()
+        now = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+
+        with patch("fenris.status.query_service_state", return_value={
+            "boot_enabled": True, "timer_active": True,
+            "last_collect_ok": None, "last_collect_age_s": None,
+            "last_collect_reason": None,
+        }):
+            result = get_status(store_path=db, clock_now=now,
+                                query_services=True, query_journal=False)
+
+        assert "monitoring: paused — deliberate disable" not in result
+
+
+# ---------------------------------------------------------------------------
+# Status output structure (§8.8, LC-9)
+# ---------------------------------------------------------------------------
+
+class TestStatusOutput:
+    """Status is a pure read-only composition (LC-9)."""
+
+    def test_status_returns_string(self, tmp_path):
+        from fenris.status import get_status
+
+        db = tmp_path / "observations.db"
+        init_store(db)
+        now = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+
+        with patch("fenris.status.query_service_state", return_value={
+            "boot_enabled": False, "timer_active": False,
+            "last_collect_ok": None, "last_collect_age_s": None,
+            "last_collect_reason": None,
+        }):
+            result = get_status(store_path=db, clock_now=now,
+                                query_services=True, query_journal=False)
+
+        assert isinstance(result, str)
+        assert len(result) > 0
+
+    def test_status_excludes_tui_identity_and_auth_notice(self, tmp_path):
+        """CLI status never renders TUI-only identity or launch guidance."""
+        from fenris.status import get_status
+
+        db = tmp_path / "observations.db"
+        init_store(db)
+        now = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+
+        with patch("fenris.status.query_service_state", return_value={
+            "boot_enabled": False, "timer_active": False,
+            "last_collect_ok": None, "last_collect_age_s": None,
+            "last_collect_reason": None,
+        }):
+            result = get_status(store_path=db, clock_now=now,
+                                query_services=True, query_journal=False)
+
+        for tui_only in (
+            "Fenris — NVMe endurance monitor",
+            "by Bongbetic",
+            "privileged actions will prompt for authentication (polkit)",
+        ):
+            assert tui_only not in result
+
+    def test_status_never_writes(self, tmp_path):
+        """Status never writes to the store."""
+        from fenris.status import get_status
+
+        db = tmp_path / "observations.db"
+        init_store(db)
+
+        mtime_before = db.stat().st_mtime
+        now = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+
+        with patch("fenris.status.query_service_state", return_value={
+            "boot_enabled": False, "timer_active": False,
+            "last_collect_ok": None, "last_collect_age_s": None,
+            "last_collect_reason": None,
+        }):
+            get_status(store_path=db, clock_now=now,
+                       query_services=True, query_journal=False)
+
+        mtime_after = db.stat().st_mtime
+        assert mtime_before == mtime_after
+
+
+# ---------------------------------------------------------------------------
+# Projection in status (§6.10)
+# ---------------------------------------------------------------------------
+
+class TestProjectionInStatus:
+    """Projection is recomputed on read, never stored (§6.10)."""
+
+    def test_store_fault_suppresses_projection(self, tmp_path):
+        from fenris.status import get_status
+
+        nonexistent = tmp_path / "nonexistent.db"
+        now = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+
+        with patch("fenris.status.query_service_state", return_value={
+            "boot_enabled": False, "timer_active": False,
+            "last_collect_ok": None, "last_collect_age_s": None,
+            "last_collect_reason": None,
+        }):
+            result = get_status(store_path=nonexistent, clock_now=now,
+                                query_services=True, query_journal=False)
+
+        assert "observation store unreadable" in result
+        assert "%" not in result  # no projection numbers
+
+    def test_newer_schema_suppresses_projection(self, tmp_path):
+        from fenris.status import get_status
+
+        db = tmp_path / "test.db"
+        conn = sqlite3.connect(str(db))
+        conn.execute("PRAGMA user_version=%d" % (SCHEMA_VERSION + 1))
+        conn.commit()
+        conn.close()
+
+        now = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+
+        with patch("fenris.status.query_service_state", return_value={
+            "boot_enabled": False, "timer_active": False,
+            "last_collect_ok": None, "last_collect_age_s": None,
+            "last_collect_reason": None,
+        }):
+            result = get_status(store_path=db, clock_now=now,
+                                query_services=True, query_journal=False)
+
+        assert "newer Fenris" in result
+        assert "upgrade Fenris" in result
+
+
+# ---------------------------------------------------------------------------
+# render_status with disclosures (CI-4)
+# ---------------------------------------------------------------------------
+
+class TestRenderStatusDisclosures:
+    """Disclosures are always available in status."""
+
+    def test_disclosures_in_output(self, tmp_path):
+        from fenris.status import render_status
+
+        db = tmp_path / "observations.db"
+        init_store(db)
+        now = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+
+        with patch("fenris.status.query_service_state", return_value={
+            "boot_enabled": False, "timer_active": False,
+            "last_collect_ok": None, "last_collect_age_s": None,
+            "last_collect_reason": None,
+        }):
+            result = render_status(store_path=db, clock_now=now,
+                                   query_services=True, query_journal=False,
+                                   show_disclosures=True)
+
+        assert "Disclosures" in result
+        assert "endurance projection" in result.lower()
+        assert "1." in result
+        assert "6." in result

tests/test_store_config.py

@@ -0,0 +1,56 @@
+"""Store path resolution from config — regression coverage for issue #53.
+
+A fresh install ships a placeholder-commented config whose only required
+key is the device selector. The collector must not crash with
+KeyError 'store_path' when the key is absent.
+"""
+import sys
+from pathlib import Path
+
+sys.path.insert(0, str(Path(__file__).parent.parent / "src"))
+
+from fenris.store import DEFAULT_STORE_PATH, get_store_path
+
+
+REPO_ROOT = Path(__file__).resolve().parent.parent
+TEMPLATE = REPO_ROOT / "packaging" / "fenris.conf"
+
+
+def _parse_like_load_config(text: str) -> dict:
+    """Mirror collect.load_config()'s key=value parsing rules."""
+    config = {}
+    for line in text.splitlines():
+        line = line.strip()
+        if not line or line.startswith("#"):
+            continue
+        if "=" in line:
+            key, value = line.split("=", 1)
+            config[key.strip()] = value.strip()
+    return config
+
+
+def test_missing_store_path_falls_back_to_default():
+    """Config with only the device selector resolves to the packaged default."""
+    assert get_store_path({"device": "/dev/nvme0n1"}) == DEFAULT_STORE_PATH
+
+
+def test_explicit_store_path_wins():
+    """An explicit store_path override is honored."""
+    assert get_store_path({"store_path": "/tmp/other.db"}) == Path("/tmp/other.db")
+
+
+def test_packaged_template_yields_collectable_config():
+    """The packaged template, once a device is set, must be collector-ready.
+
+    Reproduces the fresh-install path: parse packaging/fenris.conf the way
+    collect.load_config() does, add the device selector, then resolve the
+    store. Issue #53 made this raise KeyError.
+    """
+    config = _parse_like_load_config(TEMPLATE.read_text())
+    config["device"] = "/dev/nvme0n1"
+    assert get_store_path(config) == DEFAULT_STORE_PATH
+
+
+def test_template_documents_store_path():
+    """The template must mention store_path so admins know it is overridable."""
+    assert "store_path" in TEMPLATE.read_text()