fix: follow live activity until inspection (#102)

The _add_unattributed_bytes function was adding the same cross-hour
delta to both days when the interval spanned midnight, violating the
spec requirement to preserve measured volume once as shared boundary
evidence.

Store the unattributed bytes only on the day where the interval starts
(the earlier day). This ensures the total across both days equals the
actual delta without duplication.

Closes #88 (cross-day delta duplication portion)

CHANGELOG.md

@@ -9,6 +9,44 @@ backfill releases from before this changelog.
 
 ## [Unreleased]
 
+## [0.5.0] - 2026-09-19
+
+### Changed
+
+- Make drive activity the focus of a Chalktone dashboard with Live, Day, and History tabs, panel zoom, and fixed monitoring controls.
+- Replace block bars with labelled dotted volume plots that fit the terminal and preserve gaps, partial evidence, and point inspection.
+
+### Fixed
+
+- Preserve historical selections and store-fault messages through graph refresh and resize.
+- Show hourly drill-down results without overwriting them with a loading placeholder.
+- Keep known unallocated daily volume visible across coverage gaps, and distinguish missing hourly evidence from zero on small terminals.
+- Stage package directories with consistent public permissions, avoiding openSUSE RPM conflicts and inaccessible runtime paths when built with a restrictive umask.
+
+## [0.4.0] - 2026-09-18
+
+### Added
+
+- Show local-day read and write totals with their recorded timezone, labelled as totals so far for the current day.
+- Open the dashboard on a live three-hour written-volume graph with a read/write toggle and selected-point inspection.
+- Browse history by day from the keyboard with `[`, `]`, `g` date entry, and `t` for today and the live view.
+
+### Changed
+
+- Collect every three minutes on systemd and runit, plot live points at their actual timestamps, and retain three-minute detail for 14 days before durable summaries.
+- Withhold the endurance outlook until one full local observation day has usable evidence, then show it with categorical confidence.
+
+### Fixed
+
+- Keep midnight-spanning activity once as shared boundary evidence instead of adding it to both days.
+- Publish derived hour and day history consistently with each collection run.
+
+## [0.3.7] - 2026-09-16
+
+### Changed
+
+- Make usage-history axes, units, UTC boundaries, active 7/14/30/90-day window, gaps, partial periods, stacked write attribution, and hourly drill-down explicit; keep live graph data refreshed on the current three-minute cadence.
+
 ## [0.3.6] - 2026-09-16
 
 ### Changed

CONTEXT.md

@@ -40,6 +40,14 @@ _Avoid_: Hourly record, hourly.jsonl entry
 One row per UTC day derived from hour observations; the grain at which usage-habit evidence is judged.
 _Avoid_: Daily summary, daily stats
 
+**Usage-history window**:
+An exact consecutive span of UTC calendar days ending today, shown from day aggregates; a day without trustworthy evidence remains an explicit gap rather than disappearing or being estimated.
+_Avoid_: Available records, dataset range
+
+**Unallocated write evidence**:
+Writes known to belong to a UTC day but which cannot be assigned honestly to a particular hour; they contribute to that day's total but are never distributed across hourly bars.
+_Avoid_: Missing writes, estimated hourly writes
+
 **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

README.md

@@ -211,7 +211,7 @@ Uninstall performs the sanctioned disable first (`fenris-monitor disable --now`)
 
 ## Cadence drop-ins
 
-The default collection cadence is **5 minutes** (`OnUnitInactiveSec=5min` in the timer unit). To change it, place a systemd drop-in:
+The default collection cadence is **3 minutes** (`OnUnitInactiveSec=3min` in the timer unit). To change it, place a systemd drop-in:
 
 ```bash
 sudo systemctl edit fenris-collect.timer
@@ -223,7 +223,7 @@ sudo systemctl edit fenris-collect.timer
 No interval key exists in `/etc/fenris/fenris.conf`. Cadence is a systemd concern, not a Fenris configuration key.
 
 On Void, Fenris uses its native runit service instead: its initial collection
-is delayed by two minutes and later collections run five minutes after the
+is delayed by two minutes and later collections run three minutes after the
 previous run finishes. Inspect its state and diagnostics with:
 
 ```bash
@@ -252,6 +252,35 @@ is retried at the next interval; it never fabricates missing observations.
 
 ## Reading the dashboard
 
+![Chalktone dashboard with a dotted activity plot](assets/dashboard-chalktone.png)
+
+Preview uses synthetic observations, not measurements from a real drive.
+
+The Chalktone dashboard opens with a large **Live** activity plot. **Day** shows
+hourly evidence for a selected date, labelled UTC, and **History** shows daily
+evidence. Local-day totals keep their recorded timezone. Dotted traces show
+measured read/write volumes, not transfer speed; missing evidence breaks the
+trace. `?` marks a gap, `~` a partial total, and `u` unallocated daily volume.
+Use the selected-point readout for exact values and evidence state.
+
+Local-day totals use measured intervals inside each recorded local date. An
+interval that crosses local midnight appears once as shared evidence and stays
+outside both known totals. The dashboard labels current totals as so far and
+shows incomplete or unavailable dates without treating them as zero. Older
+UTC-only summaries cannot establish exact local-day totals.
+
+- `v` cycles Live / Day / History; the tabs are also clickable.
+- `←` / `→` inspect points; `w` switches read/write volume in every view.
+- `[` / `]` browse dates, `g` enters a date, and `t` returns to today/live.
+- `Tab` / `Shift+Tab` move focus; `z` expands the focused panel, and `z` or
+  `Esc` restores it. Monitoring status and controls remain visible.
+- `s` cycles Chalktone, Amber, Nord, and High Contrast; saved theme preferences
+  survive upgrades. `m` toggles reduced motion.
+
+On smaller terminals, textual summaries and scrollable panels keep evidence
+accessible. Pause, resume, collect, disclosures, help, and quit remain available
+in the fixed control row.
+
 Run `fenris` as your normal user to open the TUI dashboard. The dashboard does
 not need `sudo`. Use `sudo` for package installation and system configuration;
 pause, resume, and collect-now actions normally authenticate through polkit.

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

@@ -13,7 +13,7 @@ Fenris's current single process combines daemonization, a PID file, an HTTP dash
 ## 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.
+2. **Cadence.** Default three minutes: `OnBootSec=2min`, `OnUnitInactiveSec=3min` (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.

docs/adr/0010-local-day-activity-history.md

@@ -0,0 +1,11 @@
+# 10. Preserve local-day activity history with its recorded timezone
+
+Status: Accepted; legacy-history migration and repair implemented in issue #99.
+
+Fenris will retain local-day read/write summaries and the boundary evidence needed to interpret them in the existing observation store before three-minute detail expires after 14 days. Each historical summary retains its recorded timezone and day boundaries; this extends [ADR 0001](0001-observation-store-sqlite.md) while preserving the UTC hour/day evidence used for endurance projections. Collection derives new measured intervals. Ordered schema migration and explicit repair rebuild legacy summaries from surviving evidence; TUI and CLI readers remain read-only.
+
+UTC hourly summaries alone cannot recover a local day whose midnight falls inside a UTC hour. Preserving labelled local summaries trades arbitrary future timezone reinterpretation for bounded detailed-history retention; retaining all fine-grained intervals indefinitely or estimating a split from UTC summaries would violate the agreed retention or evidence semantics.
+
+Only surviving evidence may be used to derive older local summaries. Dates without enough evidence remain incomplete or unavailable; a measured interval crossing midnight is retained once as shared boundary evidence, never prorated or counted in full on both days. A later timezone change does not silently rewrite historical day boundaries.
+
+The agreed presentation and validation requirements are in the [live drive activity specification](../spec/live-drive-activity.md).

docs/research/glint-dashboard-adoption.md

@@ -0,0 +1,67 @@
+# Glint dashboard design adoption
+
+Research date: 2026-09-19. Status: feasibility findings with interview decisions in progress. This note does not authorize implementation or change Fenris's accepted behavior.
+
+## Finding
+
+Fenris can adopt a Glint-inspired terminal dashboard through an independently authored redesign of its existing Textual presentation layer. Glint is a Rust terminal application, not an HTML/CSS dashboard or a drop-in Textual component library. Its most relevant ideas are a compact pane grid, consistent title rows and metadata, obvious focus, restrained colors, and enlarging a focused pane. A wholesale Glint integration would introduce a different UI runtime, unrelated application infrastructure, and a licensing decision without being necessary to achieve this visual direction.
+
+The user has selected **Chalktone / screenshot 3**, **a large activity chart as the primary panel**, and **panel styling plus keyboard focus and zoom**. The activity panel has **Live / Day / History tabs**; enlarging a panel retains a **fixed monitoring status, freshness, and control strip**. A general dashboard builder is outside the selected scope. The developing product specification is [Glint dashboard design](../spec/glint-dashboard-design.md).
+
+## Primary-source snapshot
+
+Inspected Glint's default branch at commit [`c1d73d3e8ead2f4069630b2a237306af8f6e69c8`](https://github.com/ntrospect0/glint/tree/c1d73d3e8ead2f4069630b2a237306af8f6e69c8), committed 2026-07-19. A shallow reference checkout was created outside Fenris at `/tmp/fenris-glint-reference`.
+
+- [README](https://github.com/ntrospect0/glint/blob/c1d73d3e8ead2f4069630b2a237306af8f6e69c8/README.md) contains three dashboard screenshots, a setup screenshot, and a live-capture link. The first two dashboard screenshots use `tokyonight`; the third uses `chalktone`. They show example compositions, not one mandatory layout.
+- [Screenshot 1](https://github.com/ntrospect0/glint/blob/c1d73d3e8ead2f4069630b2a237306af8f6e69c8/docs/screenshots/glint-demo1.png), [screenshot 2](https://github.com/ntrospect0/glint/blob/c1d73d3e8ead2f4069630b2a237306af8f6e69c8/docs/screenshots/glint-demo2.png), [screenshot 3](https://github.com/ntrospect0/glint/blob/c1d73d3e8ead2f4069630b2a237306af8f6e69c8/docs/screenshots/glint-demo3.png), and [setup screenshot](https://github.com/ntrospect0/glint/blob/c1d73d3e8ead2f4069630b2a237306af8f6e69c8/docs/screenshots/glint-setup.png) are versioned in the repository. This source investigation does not substitute for visual inspection of those images.
+- [Cargo.toml](https://github.com/ntrospect0/glint/blob/c1d73d3e8ead2f4069630b2a237306af8f6e69c8/Cargo.toml) declares Rust edition 2021, package version 0.5.0, Ratatui 0.28, Crossterm 0.28, and a `glint` binary. It also brings Tokio, HTTP clients, configuration/watch infrastructure, and optional widget dependencies.
+- [GitHub repository API](https://api.github.com/repos/ntrospect0/glint), checked on the research date, reports an unarchived repository created 2026-05-27. [GitHub releases API](https://api.github.com/repos/ntrospect0/glint/releases) returned no releases. The [changelog](https://github.com/ntrospect0/glint/blob/c1d73d3e8ead2f4069630b2a237306af8f6e69c8/CHANGELOG.md) labels 0.5.0 and 0.4.0 unreleased, and README installation is from source. This is evidence of a young project and its distribution state, not proof that it is abandoned.
+- [CI configuration](https://github.com/ntrospect0/glint/blob/c1d73d3e8ead2f4069630b2a237306af8f6e69c8/.github/workflows/ci.yml) runs Cargo tests and Clippy on Ubuntu; Clippy warnings do not fail CI. Source review alone does not establish that current CI passes. No Glint build or test run was performed for this assessment.
+
+## What can transfer
+
+| Glint pattern and source | Fit for Fenris | Scope implication |
+| --- | --- | --- |
+| Pane grid with row/column spans: [layout model](https://github.com/ntrospect0/glint/blob/c1d73d3e8ead2f4069630b2a237306af8f6e69c8/src/config/layout.rs), [default configuration](https://github.com/ntrospect0/glint/blob/c1d73d3e8ead2f4069630b2a237306af8f6e69c8/src/config/defaults/config.toml). | Fenris already uses a Textual grid and rounded bordered panes. A considered re-layout can use that existing ownership. | Decide which Fenris facts deserve persistent space. A fixed layout is much smaller than Glint's user-composable dashboard system. |
+| Title integrated into the border, right-aligned metadata, focus treatment, shortcut indication: [UI title helpers](https://github.com/ntrospect0/glint/blob/c1d73d3e8ead2f4069630b2a237306af8f6e69c8/src/ui/mod.rs). | Useful for clearly named activity, history, drive, and monitoring panes. Date/range/freshness can become concise pane metadata where legible. | Independently implement the visible behavior in Fenris; do not translate or copy these GPL helpers. Ensure essential evidence is not merely truncated away. |
+| Semantic theme roles separating border, title, metadata, and text: [theme model](https://github.com/ntrospect0/glint/blob/c1d73d3e8ead2f4069630b2a237306af8f6e69c8/src/theme/mod.rs), [bundled schemes](https://github.com/ntrospect0/glint/blob/c1d73d3e8ead2f4069630b2a237306af8f6e69c8/src/config/defaults/colorschemes.toml). | Fenris already owns themes in `src/fenris/themes.py`. Extend that role system for a chosen visual direction while keeping semantic status colors and text. | Select the preferred screenshot/palette before making the default. High Contrast and reduced-motion preferences already exist and must remain usable. |
+| Tab/click focus, keyboard shortcuts, and focused-pane enlargement: [README controls](https://github.com/ntrospect0/glint/blob/c1d73d3e8ead2f4069630b2a237306af8f6e69c8/README.md), [app focus/zoom ownership](https://github.com/ntrospect0/glint/blob/c1d73d3e8ead2f4069630b2a237306af8f6e69c8/src/app.rs). | Particularly useful for graphs when a small terminal limits detail. | Zoom is new interaction behavior, not just styling. Selection/date/focus must survive entry, exit, resize, and refresh; essential fault/pause state needs a visibility decision. |
+| Multiple widgets stacked in one cell, cycled with `.`/`,`: [stack implementation](https://github.com/ntrospect0/glint/blob/c1d73d3e8ead2f4069630b2a237306af8f6e69c8/src/widgets/stack.rs). | A possible way to expose secondary details without permanent screen cost. | Hiding monitoring state, confidence, or evidence behind inactive tabs would weaken Fenris's current contract. Choose deliberately; not assumed needed. |
+| Responsive views exposing more detail at larger sizes: [view tiers](https://github.com/ntrospect0/glint/blob/c1d73d3e8ead2f4069630b2a237306af8f6e69c8/src/widgets/view_tier.rs), [widget author guide](https://github.com/ntrospect0/glint/blob/c1d73d3e8ead2f4069630b2a237306af8f6e69c8/docs/widget-sdk.md). | Useful principle, but Glint's breakpoints describe its content and are not Fenris requirements. | Preserve Fenris's constrained-terminal facts and controls, then design larger views. Do not simply reuse Glint's threshold values. |
+| Compact bottom status bar: [status bar](https://github.com/ntrospect0/glint/blob/c1d73d3e8ead2f4069630b2a237306af8f6e69c8/src/ui/status_bar.rs). | Supports a quieter action/focus rail. | Fenris has real monitoring continuity, freshness, collection outcome, authentication, and quit semantics. Its footer cannot be reduced to Glint's version/clock/theme bar. |
+
+Glint's calendar, stocks, news, email, weather, notes, galleries, external credentials, and profile/setup machinery are outside the stated Fenris redesign. Its widget SDK adds widgets inside the Rust application via a trait and registry; it is not an existing Python integration seam ([widget SDK](https://github.com/ntrospect0/glint/blob/c1d73d3e8ead2f4069630b2a237306af8f6e69c8/docs/widget-sdk.md), [widget interface](https://github.com/ntrospect0/glint/blob/c1d73d3e8ead2f4069630b2a237306af8f6e69c8/src/widgets/mod.rs)).
+
+## Fenris ownership and constraints
+
+The present application is Python with Textual, pinned to Textual 8.2.8 in [`requirements.txt`](../../requirements.txt). [`FenrisTuiApp`](../../src/fenris/tui.py) already owns the grid, header, bordered panes, compact layout, help, action bindings, and theme registration; `DailyBarGraph` and `LiveActivityGraph` already own graph selection/rendering. [`themes.py`](../../src/fenris/themes.py) owns Amber, Nord, High Contrast, and status color precedence. These are the natural extension points; a new backend or service is unnecessary for a visual redesign.
+
+The design must preserve these existing responsibilities and evidence semantics:
+
+- The collector owns privileged drive acquisition and observation-store writes; the TUI is an unprivileged reader and dispatches administrative actions through the sanctioned helper. A visual redesign does not imply a second sampler or store writer. Sources: [`CONTEXT.md`](../../CONTEXT.md), [redesign spec](../spec/fenris-redesign.md), [`tui.py`](../../src/fenris/tui.py).
+- Usage-adjusted theoretical lifespan remains a write-endurance projection, accompanied by projection confidence and supporting facts. It must not become a physical failure countdown. Unknown, unavailable, warming, stale, and store-fault states require meaningful presentation. Sources: [`CONTEXT.md`](../../CONTEXT.md), [projection ADR](../adr/0002-projection-model-sustained-regime.md), [live activity specification](../spec/live-drive-activity.md).
+- Gaps must not become zeros, and unavailable measurements must not become decorative smooth curves. Local-day labels, read/write units, incomplete evidence, selected dates, and timezone context matter. Sources: [local-day history ADR](../adr/0010-local-day-activity-history.md), [live activity specification](../spec/live-drive-activity.md).
+- Pause is a deliberate disable; quitting only leaves the TUI. Monitoring continuity, last collection outcome, and freshness must remain understandable. Sources: [service lifecycle ADR](../adr/0003-service-lifecycle-and-sanctioned-toggle.md), [dashboard clarity specification](../spec/dashboard-clarity.md), [`status_composition.py`](../../src/fenris/status_composition.py).
+- The current source switches to constrained presentation below 80 columns or 24 rows; the accepted live-activity specification requires daily totals, dates, evidence labels, confidence, and controls to remain accessible on narrow terminals. A new design must be reviewed against real target dimensions. Sources: [`tui.py`](../../src/fenris/tui.py), [live activity specification](../spec/live-drive-activity.md).
+
+The fixed Panes information architecture is normative in the older [redesign specification, section 7](../spec/fenris-redesign.md), and [dashboard clarity](../spec/dashboard-clarity.md) says it preserves that architecture and prescribes a separate quit rail. A significantly different pane hierarchy or footer should explicitly amend those presentation decisions when the user selects the new design, rather than silently treating old contracts as irrelevant. The underlying evidence and action semantics can be retained.
+
+## License boundary
+
+Glint declares **GPL-3.0-or-later** in [Cargo.toml](https://github.com/ntrospect0/glint/blob/c1d73d3e8ead2f4069630b2a237306af8f6e69c8/Cargo.toml) and source SPDX headers. Its [README license section](https://github.com/ntrospect0/glint/blob/c1d73d3e8ead2f4069630b2a237306af8f6e69c8/README.md) says distributed modified versions must remain GPL-licensed with copyright notices, and its [LICENSE](https://github.com/ntrospect0/glint/blob/c1d73d3e8ead2f4069630b2a237306af8f6e69c8/LICENSE) specifies the distribution obligations. Fenris deliberately uses MIT across source and packages under [ADR 0009](../adr/0009-mit-license.md).
+
+Copying or translating Glint implementation into an integrated distributed Fenris would therefore raise GPL compliance and licensing choices that conflict with keeping the combined implementation solely MIT. It is not an adoption route to take implicitly. The recommended route is independently authored Fenris UI code using common layout/interaction ideas observed in Glint, without copying Glint code or assets. If direct implementation reuse becomes a requirement, resolve licensing or separate permission first; this research does not establish that permission.
+
+## Interview state
+
+The selected direction is an independently implemented Chalktone-inspired dashboard with a fixed Fenris layout, an activity-first hierarchy, keyboard focus and enlargement, one activity panel with Live / Day / History tabs, and a persistent monitoring status/freshness/control strip during enlargement. Existing 80×24 support and constrained reflow are retained rather than reopened as a new minimum-size decision. The [developing design specification](../spec/glint-dashboard-design.md) owns the precise requirements and any remaining decisions; this research note is supporting evidence.
+
+No product code, glossary, ADR, or existing acceptance criteria were changed by this investigation. Keyboard focus/zoom feasibility does not establish that exact interaction behavior has been implemented or runtime-validated in Fenris.
+
+## Validation scope
+
+Evidence comes from the pinned Glint source, its checked-in documentation/screenshots, GitHub's first-party API, and Fenris's current source and accepted documents. The main design investigation visually inspected screenshots 1 and 3 and separately verified Textual grid documentation.
+
+The main investigation also reviewed synthetic renders of current Fenris at 140×44 and 80×24, after refresh cleared the launch authentication banner, using installed Textual 8.2.7 (the repository lock is 8.2.8). The captures are `/tmp/fenris-current-capture-3xdv46jm/fenris-current-140x44.png` and `/tmp/fenris-current-capture-3xdv46jm/fenris-current-80x24.png`. They showed a large blank vertical area; at 80×24 the drive, monitoring status, and actions fell below the initial viewport. This supports rearranging the panels and keeping the status/control strip visible, but is not a diagnosis of the deployed drive or proof across every state.
+
+No Glint runtime was executed, and no Glint asset was copied into the product. No accessibility audit was conducted. This research establishes architectural feasibility and records decisions; it does not claim pixel fidelity, a working integration, an upstream test result, or a measured performance result.

docs/spec/acceptance-criteria.md

@@ -49,7 +49,7 @@ Status: Accepted — resolves [Define cross-cutting acceptance criteria](https:/
 ## 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-2** (P) Timer defaults ship as `OnBootSec=2min`, `OnUnitInactiveSec=3min`, `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.

docs/spec/dashboard-clarity.md

@@ -1,5 +1,11 @@
 # Fenris dashboard clarity specification
 
+**Presentation amendment (2026-09-19):** The accepted
+[Glint-inspired dashboard design](glint-dashboard-design.md) supersedes the
+preserved Panes arrangement and standalone heavy quit rail. Identity, continuity,
+paused-state explanations, and the distinction between quitting and pausing
+remain required; quit now has an explicit entry in the fixed controls.
+
 **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*.

docs/spec/fenris-redesign.md

@@ -16,7 +16,7 @@ Every constant is defined once, in the section named below; other sections cite,
 
 | Constant | Value | Defined in |
 |---|---|---|
-| Collection cadence (default) | 5 min (`OnUnitInactiveSec`) | §8.2 |
+| Collection cadence (default) | 3 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 |
@@ -362,6 +362,12 @@ Never "82 % confidence" or "95 % accurate".
 
 ## 7. Panes TUI
 
+**Presentation amendment (2026-09-19):** The accepted
+[Glint-inspired dashboard design](glint-dashboard-design.md) supersedes this
+section's panel arrangement and graph appearance with an activity-first layout,
+dotted volume plots, Live / Day / History tabs, and focused-panel zoom. Shared
+evidence, projection, authentication, and monitoring-action contracts still apply.
+
 **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
@@ -479,7 +485,7 @@ Two privileged binaries — `/usr/libexec/fenris/fenris-collect` (device interro
 
 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);
+- **fresh** — newest sample within 2 × cadence + `AccuracySec` + 60 s (7.5 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.

docs/spec/glint-dashboard-design.md

@@ -0,0 +1,148 @@
+# Glint-inspired Fenris dashboard
+
+Status: accepted on 2026-09-19. The user confirmed the complete design and
+additionally requested Glint-style plotted graphs in place of block bars.
+
+## Purpose and reference
+
+Adopt the visual approach of [Glint](https://github.com/ntrospect0/glint) for
+Fenris's terminal dashboard. The selected visual reference is the third README
+screenshot, using Chalktone, at upstream commit
+`c1d73d3e8ead2f4069630b2a237306af8f6e69c8`:
+[reference screenshot](https://github.com/ntrospect0/glint/blob/c1d73d3e8ead2f4069630b2a237306af8f6e69c8/docs/screenshots/glint-demo3.png).
+
+The source and architectural assessment is recorded in
+[the research note](../research/glint-dashboard-adoption.md).
+
+## Confirmed user choices
+
+- Adopt panel styling, keyboard focus, and panel zoom. A freely configurable
+  dashboard builder is outside the selected scope.
+- Give the live read/write activity chart the largest opening-screen area,
+  with endurance outlook and monitoring state visible alongside it.
+- Use the muted Chalktone appearance from Glint's third screenshot as the
+  visual direction.
+- Put Live / Day / History views inside one activity panel, keeping both
+  read/write totals and the selected date visible.
+- Expand a focused panel within the dashboard while retaining a fixed strip
+  for monitoring state, observation freshness, and essential controls.
+- Replace block bars with thin dotted time-series plots resembling Glint's
+  chart. Label volume and time axes, retain exact selected-point readouts,
+  and leave explicit breaks for missing or incompatible evidence. Joining
+  adjacent measured points is visual guidance, not additional observations.
+
+## Implementation recommendation
+
+Implement the selected visual and interaction patterns independently in
+Fenris's existing Python/Textual presentation layer. Retain the collector,
+observation store, shared status/projection contracts, and authenticated control
+path. Glint is a Rust/Ratatui application under GPL-3.0-or-later; copying or
+porting its implementation into Fenris would require a separate licensing
+decision under [ADR 0009](../adr/0009-mit-license.md). Referencing general panel
+and navigation patterns does not require adopting its application architecture.
+
+Use thin borders, compact titles, an explicit focused-panel indicator, and
+restrained cream/earth-tone accents. Preserve readable contrast and semantic
+state labels; the reference's dim secondary text is not a readability target.
+Use Fenris content and identity, without Glint's unrelated clock, weather,
+finance, email, or gallery features.
+
+## Existing behavior to preserve
+
+- Activity is measured read/write volume, with both totals accessible and
+  writes selected initially. A visual stock-chart reference must not turn
+  interval volume into speed or imply continuity through unknown evidence.
+- Preserve the latest-three-hour opening view, date selection, local-day and
+  timezone labels, available history precision, and historical selection across
+  refresh under [live drive activity](live-drive-activity.md).
+- Preserve the usage-adjusted theoretical lifespan and categorical projection
+  confidence with contributing facts. Navigation and graph selection cannot
+  change the projection evidence window or endurance accounting.
+- Preserve explicit zero, gap, incomplete, unallocated, unavailable, paused,
+  stale, collection-failure, and store-fault states.
+- Keep boot enablement, runtime activity, collection outcome, and observation
+  freshness distinct. Quit leaves background monitoring running; pause remains
+  a deliberate disable through the existing control path.
+- Preserve keyboard and mouse access, constrained-terminal text/reflow,
+  high-contrast availability, reduced motion, help, and disclosures.
+
+## Concrete layout and interaction proposal
+
+- A compact identity header above one dashboard workspace.
+- A narrow supporting column for the endurance outlook and drive facts;
+  a wide activity panel receives the remaining workspace. On the normal
+  dashboard, confidence and monitoring state remain visible beside activity.
+- Live starts with the latest three hours; Day exposes the selected local
+  day's available detail; History exposes the retained longer-term evidence.
+  Reuse existing measurements and ranges rather than introducing a new data
+  model. Show selected date/timezone, read/write totals, measurement, and
+  evidence state wherever applicable.
+- Use visible, clickable tabs; Tab/Shift+Tab and mouse clicks move focus.
+  Use `z` to toggle focused-panel zoom and Escape to restore the dashboard
+  when an input/dialog is not consuming Escape. Preserve selection, date,
+  range, measurement, and focus across zoom and refresh.
+- Keep the bottom status/control area outside the expanding workspace. It
+  may wrap when required: compactness cannot merge the four service facts or
+  hide a fault/pause state. Keep quit distinct from pause in wording and
+  behavior without spending three full rows on a separate heavy quit box.
+- Use existing date-navigation and read/write shortcuts, with visible help
+  updated for tabs, focus, and zoom. Text entry must consume its own keys.
+- Use Chalktone-inspired styling as the new default while retaining existing
+  selectable themes, High Contrast, and reduced motion. Preserve an explicitly
+  saved theme preference during upgrade.
+- Design for 80×24 and larger, with existing text/reflow behavior below that
+  size. Essential facts and actions must remain accessible; the large-screen
+  reference does not require squeezing its entire density into small terminals.
+
+These defaults implement the confirmed choices. Date entry and inspection
+retain existing evidence precision: hourly/daily UTC evidence is labelled UTC,
+while local-day totals keep their recorded timezone. This visual redesign does
+not manufacture finer or local-hour precision from coarse UTC evidence.
+
+## Smallest sufficient implementation proof
+
+Render normal and zoomed views at a representative large terminal and 80×24,
+plus a constrained terminal. Check focus/tab/zoom/date/read-write interactions
+and selection persistence through refresh. Exercise paused, stale, store-fault,
+missing-baseline, and incomplete-evidence displays using existing synthetic
+stores and headless TUI patterns. Verify quit never invokes monitoring control
+and existing action tests still cover the sanctioned helper. UI fixtures are
+not evidence of the user's deployed drive state.
+
+## Specification reconciliation
+
+This accepted redesign supersedes conflicting presentation requirements in
+[the original Panes specification](fenris-redesign.md#7-panes-tui) and
+[dashboard clarity](dashboard-clarity.md): the full-width headline becomes a
+supporting endurance panel, the history/live plots share a tabbed activity
+panel, and a compact fixed control row replaces the heavy standalone quit
+rail. The block-bar requirement is superseded by dotted volume plots. Their
+behavioral requirements, including clear quit-versus-pause semantics, remain.
+
+The live-drive-activity specification excludes unrelated redesign from that
+earlier task. This is a separate design request, not permission to undo its
+accepted data, date-navigation, evidence, or forecast behavior. Existing design
+documents and source may differ in implementation status; this assessment is
+not proof that every earlier acceptance criterion has shipped.
+
+## Documentation scope
+
+No new domain term has been resolved: panel, focus, zoom, and theme are general
+interface concepts and do not belong in the domain glossary. No new ADR is
+needed for a reversible presentation change that retains the existing stack,
+license, data model, and privilege boundary. Record any later durable
+architectural trade-off separately if one emerges.
+
+## Implementation validation
+
+Implemented in Fenris's existing presentation layer with Textual 8.2.8.
+The full suite passed 801 tests; 43 packaging/signing checks were skipped for
+missing package artifacts or signing tools. After the final incomplete-evidence
+fixes, all 81 focused dashboard, history, and plot tests passed. New renderer
+and regression files pass configured Ruff checks; affected production files
+pass correctness lint and the diff passes whitespace checks. Existing broader
+lint warnings were not part of this redesign.
+
+Rendered normal and zoomed dashboards at 140×44, plus normal 80×24 and
+constrained 70×20 views. The [saved preview](../../assets/dashboard-chalktone.png)
+uses synthetic observations. No installation or release was performed.

docs/spec/xbps-proof-results.md

@@ -130,9 +130,9 @@ 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:
+Or make a one-off request without writing the configuration file:
 ```sh
-sudo xbps-install -S https://git.bongbetic.com/xavierk/Fenris-xbps/raw/branch/stable/x86_64
+sudo xbps-install -R https://git.bongbetic.com/xavierk/Fenris-xbps/raw/branch/stable/x86_64 -M -S fenris
 ```
 
 ## Publication Mechanism

packaging/release-footer.md

@@ -12,7 +12,10 @@ sudo xbps-install fenris                         # Void Linux
 For Void Linux, configure the XBPS repository first:
 
 ```bash
-sudo xbps-install -S https://git.bongbetic.com/xavierk/Fenris-xbps/raw/branch/stable/x86_64
+sudo install -d -m 0755 /etc/xbps.d
+echo 'repository=https://git.bongbetic.com/xavierk/Fenris-xbps/raw/branch/stable/x86_64' \
+  | sudo tee /etc/xbps.d/fenris.conf
+sudo xbps-install -M -S fenris
 ```
 
 ## Verify downloads

packaging/stage.sh

@@ -14,6 +14,10 @@
 #   /usr/lib/tmpfiles.d/fenris.conf
 set -euo pipefail
 
+# Package directories must be traversable by every runtime user and agree
+# with distribution-owned directories, regardless of the builder's umask.
+umask 022
+
 REPO_ROOT="$(cd "$(dirname "$0")/.." && pwd)"
 STAGE_DIR="${REPO_ROOT}/build/stage"
 

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "fenris"
-version = "0.3.6"
+version = "0.5.0"
 description = "NVMe wear monitor with persistent TUI"
 requires-python = ">=3.10"
 license = {file = "LICENSE"}

scripts/xbps-publish.sh

@@ -201,7 +201,8 @@ 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}/${ARCH}"
+echo "  echo 'repository=https://git.bongbetic.com/${GITEA_OWNER}/${GITEA_REPO}/raw/branch/${GITEA_BRANCH}/${ARCH}' | sudo tee /etc/xbps.d/fenris.conf"
+echo "  sudo xbps-install -M -S fenris"
 echo ""
 echo "Key ceremony: delete the private key after publication."
 echo "  See docs/install/signing-key-ceremony.md"

src/fenris/__init__.py

@@ -1,2 +1,2 @@
 """Fenris: NVMe wear monitor with persistent TUI."""
-__version__ = "0.3.6"
+__version__ = "0.5.0"

src/fenris/activity_plot.py

@@ -0,0 +1,104 @@
+"""A terminal volume plot shared by Fenris's activity views.
+
+Braille provides two by four dots per terminal cell. Only adjacent, complete
+measurements are connected; gaps and partial evidence never imply continuity.
+The returned columns also place mouse inspection on the plotted time axis.
+"""
+from collections.abc import Mapping, Sequence
+from dataclasses import dataclass
+
+from rich.text import Text
+
+
+@dataclass(frozen=True)
+class VolumePoint:
+    time: float
+    volume: int | None
+    label: str
+    state: str = "measured"
+
+
+def volume_plot(
+    points: Sequence[VolumePoint], width: int, height: int,
+    selected: int, colors: Mapping[str, str],
+) -> tuple[Text, list[int], str]:
+    """Render bounded axes and a dotted trace, without resampling evidence."""
+    width, height = max(12, width), max(4, height)
+    axis_width = 8
+    columns, rows = width - axis_width, height - 2
+    pixel_width, pixel_height = columns * 2, rows * 4
+    maximum = max((p.volume or 0 for p in points), default=0)
+    scale, unit = (1e12, "TB") if maximum >= 1e12 else (
+        (1e9, "GB") if maximum >= 1e9 else
+        (1e6, "MB") if maximum >= 1e6 else
+        (1e3, "KB") if maximum >= 1e3 else (1, "B")
+    )
+    ceiling = maximum or scale
+    start = points[0].time if points else 0
+    span = (points[-1].time - start) if len(points) > 1 else 0
+    xs = [round((p.time - start) / span * (pixel_width - 1)) if span else 0
+          for p in points]
+    cells = [[0] * columns for _ in range(rows)]
+    # Unicode braille dot numbering, indexed by y within cell and then x.
+    bits = ((1, 8), (2, 16), (4, 32), (64, 128))
+
+    def dot(x: int, y: int) -> None:
+        cells[y // 4][x // 2] |= bits[y % 4][x % 2]
+
+    previous = None
+    markers = {}
+    for index, (point, x) in enumerate(zip(points, xs)):
+        if point.volume is None:
+            previous = None
+            if point.state != "future":
+                markers[x // 2] = "?"
+            continue
+        y = round((1 - point.volume / ceiling) * (pixel_height - 1))
+        y = min(pixel_height - 1, max(0, y))
+        if previous is not None and point.state == "measured":
+            px, py = previous
+            steps = max(abs(x - px), abs(y - py), 1)
+            for step in range(steps + 1):
+                dot(round(px + (x - px) * step / steps),
+                    round(py + (y - py) * step / steps))
+        dot(x, y)
+        previous = (x, y) if point.state == "measured" else None
+        if point.state != "measured":
+            markers[x // 2] = "~" if point.state == "partial" else "u"
+        elif point.volume == 0:
+            markers.setdefault(x // 2, "·")
+
+    selected_column = xs[selected] // 2 if 0 <= selected < len(xs) else -1
+    result = Text(no_wrap=True, overflow="crop")
+    ticks = {0, rows // 2, rows - 1}
+    for row, values in enumerate(cells):
+        value = ceiling * (rows - 1 - row) / max(1, rows - 1) / scale
+        label = f"{value:6.2f}"[-6:] if row in ticks else "      "
+        result.append(label + " │", style=colors["muted"])
+        for col, value in enumerate(values):
+            char = chr(0x2800 + value) if value else " "
+            style = colors["allocated"]
+            if col == selected_column:
+                style = "bold " + colors["selection"]
+                if not value:
+                    char = "┊"
+                    style = colors["muted"]
+            result.append(char, style=style)
+        result.append("\n")
+    result.append("       └", style=colors["muted"])
+    for col in range(columns):
+        result.append("▼" if col == selected_column else markers.get(col, "─"),
+                      style=colors["selection"] if col == selected_column else colors["muted"])
+    result.append("\n" + " " * axis_width)
+    labels = [" "] * columns
+    end_of_label = -1
+    for index in sorted({0, len(points) // 2, len(points) - 1}):
+        if index < 0 or not points:
+            continue
+        label = points[index].label[:columns]
+        column = max(0, min(columns - len(label), xs[index] // 2 - len(label) // 2))
+        if column > end_of_label:
+            labels[column:column + len(label)] = label
+            end_of_label = column + len(label)
+    result.append("".join(labels), style=colors["muted"])
+    return result, [axis_width + x // 2 for x in xs], unit

src/fenris/activity_selection.py

@@ -0,0 +1,108 @@
+"""User choices for live and historical activity views."""
+from collections.abc import Sequence
+from dataclasses import dataclass
+
+HISTORY_RANGE_DEFAULT = 14
+
+
+@dataclass(frozen=True)
+class IntervalIdentity:
+    """Stable identity for one measured interval."""
+
+    start_ts: str
+    end_ts: str
+
+
+class ActivitySelection:
+    """Keep activity navigation state separate from its Textual rendering."""
+
+    def __init__(self) -> None:
+        self.view = "live"
+        self.browse_date: str | None = None
+        self.selected_history_hour: str | None = None
+        self.history_range_days = HISTORY_RANGE_DEFAULT
+        self.measure = "written"
+        self.following_live = True
+        self.selected_live_interval: IntervalIdentity | None = None
+        self.live_interval_expired = False
+
+    def set_view(self, view: str) -> None:
+        """Select live, day, or history view."""
+        if view not in ("live", "day", "history"):
+            raise ValueError(f"unknown activity view: {view}")
+        self.view = view
+        if view == "live":
+            self.follow_live()
+
+    def select_history_date(self, date: str | None) -> None:
+        """Keep the chosen historical local date across refresh."""
+        if date != self.browse_date:
+            self.selected_history_hour = None
+        self.browse_date = date
+
+    def select_history_hour(self, hour: str | None) -> None:
+        """Keep the chosen historical hour across refresh."""
+        self.selected_history_hour = hour
+
+    def toggle_measure(self) -> str:
+        """Switch read/write presentation without changing point selection."""
+        self.measure = "read" if self.measure == "written" else "written"
+        return self.measure
+
+    def follow_live(self) -> None:
+        """Resume following the newest interval and clear stale-pin notices."""
+        self.view = "live"
+        self.browse_date = None
+        self.selected_history_hour = None
+        self.following_live = True
+        self.selected_live_interval = None
+        self.live_interval_expired = False
+
+    def update_live(self, intervals: Sequence[IntervalIdentity]) -> None:
+        """Reconcile the selected interval with the rolling live window."""
+        if self.following_live:
+            self.selected_live_interval = intervals[-1] if intervals else None
+            return
+        if self.selected_live_interval in intervals:
+            return
+
+        self.following_live = True
+        self.selected_live_interval = intervals[-1] if intervals else None
+        self.live_interval_expired = True
+
+    def move_live(
+        self, intervals: Sequence[IntervalIdentity], offset: int,
+    ) -> IntervalIdentity | None:
+        """Inspect an adjacent interval by stable identity."""
+        if not intervals:
+            return None
+        if self.selected_live_interval in intervals:
+            current = intervals.index(self.selected_live_interval)
+        else:
+            current = len(intervals) - 1
+        selected = intervals[max(0, min(len(intervals) - 1, current + offset))]
+        self._pin_live_interval(selected)
+        return selected
+
+    def inspect_live(
+        self,
+        intervals: Sequence[IntervalIdentity],
+        interval: IntervalIdentity,
+    ) -> None:
+        """Pin the interval chosen by mouse inspection."""
+        if interval in intervals:
+            self._pin_live_interval(interval)
+
+    def selected_live_index(self, intervals: Sequence[IntervalIdentity]) -> int:
+        """Return the selected point's current render index, or -1."""
+        if self.selected_live_interval is None:
+            return -1
+        try:
+            return intervals.index(self.selected_live_interval)
+        except ValueError:
+            return -1
+
+    def _pin_live_interval(self, interval: IntervalIdentity) -> None:
+        self.selected_live_interval = interval
+        self.following_live = False
+        self.live_interval_expired = False

src/fenris/collect.py

@@ -27,7 +27,6 @@ if VENV_DIR.exists():
         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
 
 
@@ -103,14 +102,6 @@ def main() -> None:
         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):
@@ -118,11 +109,24 @@ def main() -> None:
 
         clock = SimpleClock()
 
+        def acquire():
+            """Interrogate the drive after pending-work preflight."""
+            smartctl_data = interrogate_drive(device)
+            sysfs_path = find_nvme_sysfs()
+            if sysfs_path is None:
+                raise RuntimeError("No NVMe controller found in sysfs")
+            return smartctl_data, sysfs_path
+
         # Run collection
-        result = run_collection(smartctl_data, sysfs_path, config, clock)
+        result = run_collection(config=config, clock=clock, acquire=acquire)
 
         if result["ok"]:
             print(f"Collection successful: {result['sample_count']} sample(s)")
+            if result.get("retention_error"):
+                print(
+                    f"Retention deferred: {result['retention_error']}",
+                    file=sys.stderr,
+                )
             sys.exit(0)
         else:
             print(f"Collection failed: {result['error']}", file=sys.stderr)

src/fenris/collector.py

@@ -5,19 +5,21 @@ This module implements the thinnest complete write path:
 - Acquire controller identity from sysfs
 - Normalize identity exactly once at write time
 - Validate every row against store invariants
-- Commit one well-formed sample
+- Stage valid observations privately before derivation
+- Publish the sample and derived evidence in one collection-owned transaction
 
 No code path outside the collector interrogates the device.
 """
 import json
 import sqlite3
+from collections.abc import Callable
 from datetime import datetime, timezone
 from pathlib import Path
-from typing import Any, Dict, Optional, Tuple
+from typing import Any, Dict, Optional
 
-from .store import init_store, get_store_path
+from .derive import derive_hours_from_interval, find_previous_sample
 from .monitoring_periods import ensure_period_open
-from .derive import find_previous_sample, derive_hours_from_interval
+from .store import init_store, get_store_path
 
 
 class AcquisitionError(Exception):
@@ -30,6 +32,29 @@ class InvariantViolationError(Exception):
     pass
 
 
+class _PendingDerivationError(Exception):
+    """A valid staged observation failed while deriving dependent evidence."""
+
+    def __init__(self, cause: Exception):
+        super().__init__(str(cause))
+        self.cause = cause
+
+
+class _PendingRecoveryFailure(Exception):
+    """A publication attempt failed after earlier pending rows committed."""
+
+    def __init__(self, error: Exception, published_count: int):
+        derivation_error = isinstance(error, _PendingDerivationError)
+        cause = error.cause if derivation_error else error
+        super().__init__(str(cause))
+        self.cause = cause
+        self.published_count = published_count
+        self.derivation_error = derivation_error
+
+
+PENDING_PUBLICATION_LIMIT = 6720
+
+
 def acquire_from_smartctl(smartctl_data: Dict[str, Any]) -> Dict[str, Any]:
     """Acquire counters and thermal evidence from smartctl -a -j data.
     
@@ -195,12 +220,12 @@ def write_sample(
     sample: Dict[str, Any],
     identity: Dict[str, Any],
     conn: sqlite3.Connection,
-    clock,
+    observed_at: datetime,
 ) -> Dict[str, Any]:
     """Write one sample to the observation store.
     
     Identity normalization happens exactly once here.
-    Returns segment info for the caller.
+    Returns segment info for the caller. Caller owns the transaction.
     """
     from .segment import find_current_segment, should_open_new_segment, open_segment
     
@@ -219,8 +244,7 @@ def write_sample(
     # Open new segment if needed
     segment_opened = False
     if should_open:
-        now = clock.utcnow()
-        open_segment(conn, now, identity, identity_key, identity_degraded)
+        open_segment(conn, observed_at, identity, identity_key, identity_degraded)
         segment_opened = True
     
     # Get current segment_id for provenance
@@ -235,8 +259,8 @@ def write_sample(
             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 (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+            critical_warning, segment_id, local_tz
+        ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
         """,
         (
             sample["ts"],
@@ -259,76 +283,45 @@ def write_sample(
             sample["bytes_read"],
             sample["critical_warning"],
             segment_id,
+            sample.get("local_tz"),
         ),
     )
     
-    conn.commit()
-    
     return {
         "segment_opened": segment_opened,
         "segment_reason": reason,
         "identity_key": identity_key,
         "identity_degraded": identity_degraded,
         "segment_id": segment_id,
+        "sample_id": cursor.lastrowid,
     }
 
 
-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)
+def _observation_time(sample: Dict[str, Any]) -> datetime:
+    """Read an observation's original timestamp for ordered recovery."""
+    observed_at = datetime.fromisoformat(sample["ts"])
+    if observed_at.tzinfo is None:
+        return observed_at.replace(tzinfo=timezone.utc)
+    return observed_at.astimezone(timezone.utc)
 
 
-        try:
-            # Ensure monitoring period is open (issue #73 AC2)
-            ensure_period_open(conn, clock.utcnow())
-            
-            # Validate invariants
+def _publish_observation(
+    conn: sqlite3.Connection,
+    sample: Dict[str, Any],
+    identity: Dict[str, Any],
+    tz_name: str,
+) -> None:
+    """Publish one staged sample and all dependent evidence in caller transaction."""
+    observed_at = _observation_time(sample)
+    sample["local_tz"] = tz_name
     validate_sample_invariants(sample, conn)
+    ensure_period_open(conn, observed_at)
+    seg_info = write_sample(sample, identity, conn, observed_at)
 
-            # 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]
-                
+    current_id = seg_info["sample_id"]
     prev = find_previous_sample(conn, seg_info.get("segment_id"), current_id)
+    try:
         if prev is not None:
-                    # Build current sample dict for derivation
             current = {
                 "id": current_id,
                 "ts": sample["ts"],
@@ -338,23 +331,253 @@ def run_collection(
                 "temperature_c": sample["temperature_c"],
                 "data_units_written": sample["data_units_written"],
                 "data_units_read": sample["data_units_read"],
+                "local_tz": tz_name,
             }
             derive_hours_from_interval(conn, prev, current)
-            except Exception:
-                # Derivation failure must not prevent sample persistence (issue #73 AC6)
-                pass
+            from .local_day import record_local_activity_interval
+            record_local_activity_interval(
+                conn,
+                prev,
+                current,
+                start_sample_id=prev["id"],
+                end_sample_id=current_id,
+                segment_id=seg_info.get("segment_id"),
+            )
+        else:
+            previous_any_segment = find_previous_sample(conn, None, current_id)
+            if previous_any_segment is not None:
+                from .local_day import mark_local_activity_gap
+                mark_local_activity_gap(
+                    conn,
+                    sample["ts"],
+                    tz_name,
+                    previous_any_segment,
+                )
 
+        from .day_aggregate import derive_all_days, persist_day_aggregate
+        for aggregate in derive_all_days(conn):
+            persist_day_aggregate(conn, aggregate)
+
+        from .local_day import derive_local_day_summary, persist_local_day
+        local_summary = derive_local_day_summary(conn, tz_name, observed_at)
+        if local_summary is not None:
+            persist_local_day(conn, local_summary)
+    except Exception as exc:  # noqa: BLE001 - preserve valid staged evidence for retry.
+        raise _PendingDerivationError(exc) from exc
+
+
+def _pending_count(conn: sqlite3.Connection) -> int:
+    return conn.execute("SELECT COUNT(*) FROM pending_publications").fetchone()[0]
+
+
+def _stage_observation(
+    conn: sqlite3.Connection,
+    sample: Dict[str, Any],
+    identity: Dict[str, Any],
+    tz_name: str,
+) -> int:
+    """Durably stage valid acquired evidence before attempting publication."""
+    payload = json.dumps(
+        {"sample": sample, "identity": identity, "tz_name": tz_name},
+        separators=(",", ":"),
+        sort_keys=True,
+    )
+    cursor = conn.execute(
+        "INSERT INTO pending_publications (sample_ts, payload) VALUES (?, ?)",
+        (sample["ts"], payload),
+    )
+    return cursor.lastrowid
+
+
+def _recover_pending(conn: sqlite3.Connection) -> int:
+    """Publish pending observations oldest first; stop at first failure."""
+    recovered = 0
+    while True:
+        conn.execute("BEGIN IMMEDIATE")
+        try:
+            row = conn.execute(
+                "SELECT id, payload FROM pending_publications ORDER BY id LIMIT 1"
+            ).fetchone()
+            if row is None:
+                conn.rollback()
+                return recovered
+
+            pending_id, payload = row
+            observation = json.loads(payload)
+            try:
+                _publish_observation(
+                    conn,
+                    observation["sample"],
+                    observation["identity"],
+                    observation["tz_name"],
+                )
+            except Exception as exc:
+                raise _PendingRecoveryFailure(exc, recovered) from exc
+            conn.execute("DELETE FROM pending_publications WHERE id = ?", (pending_id,))
+            conn.commit()
+            recovered += 1
+        except Exception:
+            conn.rollback()
+            raise
+
+
+def _is_store_or_invariant_failure(exc: Exception) -> bool:
+    return (
+        isinstance(exc, sqlite3.Error)
+        and not isinstance(exc, sqlite3.IntegrityError)
+    ) or isinstance(exc, InvariantViolationError)
+
+
+def _pending_capacity_error(
+    reason: str,
+    *,
+    acquisition_skipped: bool = False,
+) -> RuntimeError:
+    outcome = "; no new observation acquired" if acquisition_skipped else ""
+    return RuntimeError(
+        "pending publication capacity full "
+        f"({PENDING_PUBLICATION_LIMIT} observations){outcome}; "
+        f"{reason}"
+    )
+
+
+def _recover_pending_for_collection(conn: sqlite3.Connection) -> int:
+    """Retry queued work and report exhausted capacity without masking store faults."""
+    try:
+        return _recover_pending(conn)
+    except Exception as exc:  # noqa: BLE001 - preserve pending evidence on recovery errors.
+        cause = exc.cause if isinstance(exc, _PendingRecoveryFailure) else exc
+        if _is_store_or_invariant_failure(cause):
+            raise cause
+        try:
+            capacity_full = _pending_count(conn) >= PENDING_PUBLICATION_LIMIT
+        except sqlite3.Error:
+            raise cause
+        if capacity_full:
+            raise _pending_capacity_error(f"recovery failed: {cause}") from cause
+        raise cause
+
+
+def _recover_pending_for_admission(conn: sqlite3.Connection) -> int:
+    """Recover in order, then admit one observation if bounded space remains."""
+    try:
+        recovered = _recover_pending(conn)
+    except _PendingRecoveryFailure as failure:
+        if (
+            not failure.derivation_error
+            or _is_store_or_invariant_failure(failure.cause)
+        ):
+            raise failure.cause
+        try:
+            pending_count = _pending_count(conn)
+        except sqlite3.Error:
+            raise failure.cause
+        if pending_count >= PENDING_PUBLICATION_LIMIT:
+            raise _pending_capacity_error(
+                f"recovery failed: {failure.cause}",
+                acquisition_skipped=True,
+            ) from failure.cause
+        return failure.published_count
+
+    if _pending_count(conn) >= PENDING_PUBLICATION_LIMIT:
+        raise _pending_capacity_error(
+            "recovery left the queue full",
+            acquisition_skipped=True,
+        )
+    return recovered
+
+
+def run_collection(
+    smartctl_data: Optional[Dict[str, Any]] = None,
+    sysfs_path: Optional[Path] = None,
+    config: Optional[Dict[str, Any]] = None,
+    clock=None,
+    *,
+    acquire: Optional[Callable[[], tuple[Dict[str, Any], Path]]] = None,
+) -> Dict[str, Any]:
+    """Recover old work, acquire one observation, then publish it atomically.
+
+    Production callers pass ``acquire`` so recovery and capacity checks run
+    before device interrogation. Direct sample arguments remain useful for
+    deterministic collector tests.
+    """
+    conn = None
+    try:
+        if config is None or clock is None:
+            raise ValueError("config and clock are required")
+
+        store_path = get_store_path(config)
+        conn = init_store(store_path)
+
+        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)
+
+        published_count = _recover_pending_for_admission(conn)
+        checked_pending_count = _pending_count(conn)
+
+        # Hold the writer reservation across the capacity check and acquisition.
+        # Recheck recovery if another collector appended work during preflight.
+        while True:
+            conn.execute("BEGIN IMMEDIATE")
+            waiting = _pending_count(conn)
+            if (
+                waiting >= PENDING_PUBLICATION_LIMIT
+                or waiting > checked_pending_count
+            ):
+                conn.rollback()
+                published_count += _recover_pending_for_admission(conn)
+                checked_pending_count = _pending_count(conn)
+                continue
+
+            from .tz_util import detect_system_tz
+            tz_name = detect_system_tz()
+            if acquire is not None:
+                smartctl_data, sysfs_path = acquire()
+            if smartctl_data is None or sysfs_path is None:
+                raise AcquisitionError("No acquired SMART data or sysfs identity")
+
+            counters = acquire_from_smartctl(smartctl_data)
+            identity = acquire_from_sysfs(sysfs_path)
+            sample = {
+                "ts": clock.utcnow().isoformat(),
+                "device": config["device"],
+                **counters,
+                **identity,
+            }
+            validate_sample_invariants(sample, conn)
+            _stage_observation(conn, sample, identity, tz_name)
+            conn.commit()
+            break
+
+        published_count += _recover_pending_for_collection(conn)
+        retention_error = None
+        try:
+            if _pending_count(conn) == 0:
+                from .pruning import prune_old_samples
+
+                prune_old_samples(conn, clock.utcnow())
+        except Exception as exc:  # noqa: BLE001 - publication already committed.
+            # Publication already committed. Keep collection successful and
+            # retry atomic retention on the next normal collection.
+            conn.rollback()
+            retention_error = str(exc)
         return {
             "ok": True,
-                "sample_count": 1,
+            "sample_count": published_count,
+            "retention_error": retention_error,
             "store_path": str(store_path),
         }
-        finally:
-            conn.close()
 
-    except (AcquisitionError, InvariantViolationError) as e:
+    except Exception as exc:
+        if conn is not None:
+            conn.rollback()
         return {
             "ok": False,
-            "error": str(e),
-            "error_type": type(e).__name__,
+            "error": str(exc),
+            "error_type": type(exc).__name__,
         }
+    finally:
+        if conn is not None:
+            conn.close()

src/fenris/day_aggregate.py

@@ -163,3 +163,41 @@ def derive_all_days(conn: sqlite3.Connection) -> list[DayAggregate]:
         if agg is not None:
             results.append(agg)
     return results
+
+
+def persist_day_aggregate(conn: sqlite3.Connection, agg: DayAggregate) -> None:
+    """Upsert a derived day aggregate into the day_aggregates table.
+
+    Merges attributed bytes from hour observations with any existing
+    unattributed cross-hour evidence already stored for this day.
+    Caller must manage transactions and commits.
+    """
+    existing = conn.execute(
+        "SELECT id FROM day_aggregates WHERE day = ?",
+        (agg.day,),
+    ).fetchone()
+
+    if existing is None:
+        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 (?, ?, ?, ?, ?, ?, ?, ?, ?)",
+            (agg.day, agg.seconds_active, agg.seconds_idle,
+             agg.seconds_powered_off, agg.seconds_unknown,
+             agg.bytes_written_delta, agg.bytes_read_delta,
+             agg.sample_count, agg.coverage),
+        )
+    else:
+        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 id = ?",
+            (agg.seconds_active, agg.seconds_idle,
+             agg.seconds_powered_off, agg.seconds_unknown,
+             agg.bytes_written_delta, agg.bytes_read_delta,
+             agg.sample_count, agg.coverage,
+             existing[0]),
+        )

src/fenris/derive.py

@@ -29,7 +29,7 @@ def find_previous_sample(
     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 "
+            "       temperature_c, data_units_written, data_units_read, local_tz "
             "FROM samples WHERE id < ? AND segment_id = ? "
             "ORDER BY id DESC LIMIT 1",
             (current_sample_id, segment_id),
@@ -37,7 +37,7 @@ def find_previous_sample(
     else:
         cursor = conn.execute(
             "SELECT id, ts, bytes_written, bytes_read, power_on_hours, "
-            "       temperature_c, data_units_written, data_units_read "
+            "       temperature_c, data_units_written, data_units_read, local_tz "
             "FROM samples WHERE id < ? "
             "ORDER BY id DESC LIMIT 1",
             (current_sample_id,),
@@ -49,7 +49,7 @@ def find_previous_sample(
         "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],
+        "data_units_read": row[7], "local_tz": row[8],
     }
 
 
@@ -96,6 +96,7 @@ def derive_hours_from_interval(
     """Derive hour observations from a sample pair interval.
 
     Returns list of hour observation dicts that were written/updated.
+    Caller owns the transaction.
     """
     prev_ts = _parse_ts(prev_sample["ts"])
     next_ts = _parse_ts(next_sample["ts"])
@@ -175,7 +176,8 @@ def _upsert_hour_observation(
     """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 = ?",
+        "SELECT id, bytes_written_delta, bytes_read_delta, sample_count "
+        "FROM hour_observations WHERE hour = ?",
         (hour_key,),
     ).fetchone()
 
@@ -198,14 +200,14 @@ def _upsert_hour_observation(
     else:
         # Merge: accumulate bytes and sample count
         new_bw = existing[1] + bw_delta
-        new_samples = existing[2] + sample_count
+        new_br = existing[2] + br_delta
+        new_samples = existing[3] + sample_count
         conn.execute(
-            "UPDATE hour_observations SET bytes_written_delta = ?, sample_count = ? WHERE id = ?",
-            (new_bw, new_samples, existing[0]),
+            "UPDATE hour_observations "
+            "SET bytes_written_delta = ?, bytes_read_delta = ?, sample_count = ? "
+            "WHERE id = ?",
+            (new_bw, new_br, new_samples, existing[0]),
         )
-    conn.commit()
-
-
 def _add_unattributed_bytes(
     conn: sqlite3.Connection,
     prev_ts: datetime,
@@ -213,12 +215,15 @@ def _add_unattributed_bytes(
     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")
+    """Store unattributed byte deltas once as shared boundary evidence.
+
+    A cross-midnight interval's delta is preserved on the day where it
+    STARTS (the earlier day).  It is not duplicated into both days;
+    the spec requires preserving the measured volume once as shared
+    unallocated boundary evidence (issue #88).
+    """
+    day = prev_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()
@@ -234,4 +239,3 @@ def _add_unattributed_bytes(
             "unattributed_bytes_read = unattributed_bytes_read + ? WHERE day = ?",
             (bw_delta, br_delta, day),
         )
-    conn.commit()

src/fenris/init_system.py

@@ -10,13 +10,13 @@ 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/run        — scheduler (sleep 120; loop { collect; sleep 180 })
   /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)
+  - Completion-relative 3-minute cadence (sleep 180 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)

src/fenris/monitor.py

@@ -69,6 +69,7 @@ def cmd_enable(args: argparse.Namespace) -> None:
         open_period = get_open_period(conn)
         if open_period is None:
             ensure_period_open(conn, now)
+            conn.commit()
             print("Monitoring period opened at", now.isoformat())
         else:
             print("Monitoring period already open (id=%d)" % open_period["id"])

src/fenris/monitoring_periods.py

@@ -16,7 +16,7 @@ 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.
+    at the run moment, never backdated. Caller owns the transaction.
     """
     if get_open_period(conn) is not None:
         return  # Already open — no-op
@@ -26,7 +26,6 @@ def ensure_period_open(conn: sqlite3.Connection, run_time: datetime) -> None:
         "INSERT INTO monitoring_periods (started_at) VALUES (?)",
         (ts,),
     )
-    conn.commit()
 
 
 def close_period(

src/fenris/preferences.py

@@ -19,8 +19,8 @@ from typing import Any, Dict
 
 
 PREFERENCE_FILE_NAME = "preferences.json"
-VALID_THEMES = {"amber", "nord", "high_contrast"}
-DEFAULT_THEME = "amber"
+VALID_THEMES = {"chalktone", "amber", "nord", "high_contrast"}
+DEFAULT_THEME = "chalktone"
 DEFAULT_REDUCED_MOTION = False
 
 
@@ -46,7 +46,7 @@ def load_preferences() -> Dict[str, Any]:
       reduced_motion: bool
 
     If the file is missing, corrupt, unreadable, or contains invalid
-    values, returns safe defaults (Amber theme, normal motion).
+    values, returns safe defaults (Chalktone theme, normal motion).
     """
     path = get_preference_path()
 

src/fenris/projection.py

@@ -187,7 +187,7 @@ def _wall_clock_in_range(conn, start, end):
 
 def _resolve_baseline(conn, current_segment):
     baseline = _get_baseline(conn)
-    facts = []
+    facts: list[str] = []
     if baseline is None:
         return BaselineTier.NONE, None, "no baseline", facts
 
@@ -483,6 +483,31 @@ def _build_pu_context_line(conn, rate, days, clock_now):
     return "Percentage Used: %d%%" % pu
 
 
+# ---------------------------------------------------------------------------
+# Complete observation day gate (issue #94)
+# ---------------------------------------------------------------------------
+
+def _has_complete_local_day(conn):
+    """Check if at least one complete local observation day exists.
+
+    A complete local day is a full midnight-to-midnight calendar day
+    within a monitoring period that has usable observation evidence.
+    This is the prerequisite for showing an endurance outlook.
+    """
+    return _count_complete_local_days(conn) > 0
+
+
+def _count_complete_local_days(conn):
+    """Count the number of complete local observation days."""
+    row = conn.execute(
+        "SELECT COUNT(*) FROM local_days "
+        "WHERE complete = 1 "
+        "AND activity_precision IN ('measured', 'coarse') "
+        "AND activity_intervals > 0"
+    ).fetchone()
+    return row[0] if row else 0
+
+
 # ---------------------------------------------------------------------------
 # Main projection function
 # ---------------------------------------------------------------------------
@@ -499,6 +524,30 @@ def compute_projection(conn, clock_now):
     tier, baseline, baseline_label, baseline_facts = _resolve_baseline(conn, current_segment)
     facts.extend(baseline_facts)
 
+    # --- Complete observation day gate (issue #94) ---
+    # An endurance outlook requires at least one complete local
+    # midnight-to-midnight calendar day with usable observation evidence.
+    has_complete_day = _has_complete_local_day(conn)
+    if not has_complete_day:
+        facts.append("waiting for a full local observation day")
+        return ProjectionResult(
+            confidence_state=ConfidenceState.UNSUPPORTED,
+            contributing_facts=facts,
+            headline_remaining_seconds=None,
+            scenario_range=None,
+            pu_context_line="Percentage Used: unknown" if _get_latest_pu(conn) is None else "Percentage Used: %d%%" % (_get_latest_pu(conn) or 0),
+            disclosure_text=list(DISCLOSURES),
+            baseline_tier=tier,
+            baseline_label=baseline_label,
+            regime_days=None,
+            habit_change_fact=None,
+            warming_fact=None,
+            staleness_fact=None,
+            degraded_identity_fact=None,
+            zero_rate_fact=None,
+            qualifying_days_progress=None,
+        )
+
     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)
 

src/fenris/pruning.py

@@ -1,125 +1,332 @@
-"""Raw sample pruning per spec §3.4, ST-5.
+"""Expire detail only after UTC and local_days replacement evidence is durable.
 
-Raw samples are pruned opportunistically to 14 days.
-Hour observations and day aggregates are retained indefinitely.
-Boundary anchors required for successor evidence are retained.
+The 14-day cutoff never overrides local-day preservation, shared boundary
+evidence, publication recovery, or the newest sample's successor-anchor role.
 """
 import sqlite3
-from datetime import datetime, timedelta, timezone
+from datetime import date, datetime, timedelta, timezone
 
-# Spec §3.4: Raw-sample retention
 RAW_SAMPLE_RETENTION_DAYS = 14
 
 
+def _utc_datetime(value: datetime) -> datetime:
+    """Normalize a clock value to aware UTC."""
+    if value.tzinfo is None:
+        value = value.replace(tzinfo=timezone.utc)
+    return value.astimezone(timezone.utc)
+
+
+def _parse_sample_time(value: str) -> datetime | None:
+    """Parse old timestamps conservatively; malformed legacy values stay."""
+    try:
+        parsed = datetime.fromisoformat(value)
+    except (TypeError, ValueError):
+        return None
+    return _utc_datetime(parsed)
+
+
+def _sample_rows(conn: sqlite3.Connection) -> list[tuple]:
+    return conn.execute(
+        "SELECT id, ts, segment_id, bytes_written, bytes_read, local_tz "
+        "FROM samples ORDER BY id"
+    ).fetchall()
+
+
+def _required_hour_window(
+    start: datetime,
+    end: datetime,
+) -> tuple[datetime, datetime, int] | None:
+    """Return first hour, exclusive end and count for [start, end)."""
+    if end <= start:
+        return None
+    first_hour = start.replace(minute=0, second=0, microsecond=0)
+    last_hour = end.replace(minute=0, second=0, microsecond=0)
+    try:
+        exclusive_end = last_hour if end == last_hour else last_hour + timedelta(hours=1)
+    except OverflowError:
+        return None
+    count = int((exclusive_end - first_hour).total_seconds() // 3600)
+    return first_hour, exclusive_end, count
+
+
+def _has_utc_replacement(
+    conn: sqlite3.Connection,
+    previous: tuple,
+    current: tuple,
+    start: datetime,
+    end: datetime,
+) -> bool:
+    window = _required_hour_window(start, end)
+    if window is None:
+        return False
+    first_hour, exclusive_end, expected_hour_count = window
+
+    actual_hour_count = conn.execute(
+        "SELECT COUNT(*) FROM hour_observations WHERE hour >= ? AND hour < ?",
+        (
+            first_hour.strftime("%Y-%m-%dT%H:00:00+00:00"),
+            exclusive_end.strftime("%Y-%m-%dT%H:00:00+00:00"),
+        ),
+    ).fetchone()[0]
+    if actual_hour_count < expected_hour_count:
+        return False
+
+    start_written, end_written = previous[3], current[3]
+    start_read, end_read = previous[4], current[4]
+    if None in (start_written, end_written, start_read, end_read):
+        return False
+    if end_written < start_written or end_read < start_read:
+        return False
+    bytes_written = end_written - start_written
+    bytes_read = end_read - start_read
+    if expected_hour_count == 1:
+        totals = conn.execute(
+            "SELECT bytes_written_delta, bytes_read_delta FROM hour_observations "
+            "WHERE hour = ?",
+            (first_hour.strftime("%Y-%m-%dT%H:00:00+00:00"),),
+        ).fetchone()
+    else:
+        totals = conn.execute(
+            "SELECT unattributed_bytes_written, unattributed_bytes_read "
+            "FROM day_aggregates WHERE day = ?",
+            (start.date().isoformat(),),
+        ).fetchone()
+    if totals is None or totals[0] < bytes_written or totals[1] < bytes_read:
+        return False
+
+    last_day = (exclusive_end - timedelta(microseconds=1)).date()
+    expected_day_count = (last_day - first_hour.date()).days + 1
+    actual_day_count = conn.execute(
+        "SELECT COUNT(*) FROM day_aggregates WHERE day >= ? AND day <= ?",
+        (first_hour.date().isoformat(), last_day.isoformat()),
+    ).fetchone()[0]
+    return actual_day_count >= expected_day_count
+
+
+def _local_day_row_exists(
+    conn: sqlite3.Connection,
+    local_date: str,
+    tz_name: str,
+) -> bool:
+    return conn.execute(
+        "SELECT 1 FROM local_days WHERE local_date = ? AND tz_name = ?",
+        (local_date, tz_name),
+    ).fetchone() is not None
+
+
+def _local_day_bounds(
+    conn: sqlite3.Connection,
+    local_date: str,
+    tz_name: str,
+) -> tuple[datetime, datetime] | None:
+    row = conn.execute(
+        "SELECT utc_start, utc_end FROM local_days "
+        "WHERE local_date = ? AND tz_name = ?",
+        (local_date, tz_name),
+    ).fetchone()
+    if row is None:
+        return None
+    start = _parse_sample_time(row[0])
+    end = _parse_sample_time(row[1])
+    if start is None or end is None or end <= start:
+        return None
+    return start, end
+
+
+def _contains_instant(
+    conn: sqlite3.Connection,
+    local_date: str,
+    tz_name: str,
+    instant: datetime,
+) -> bool:
+    bounds = _local_day_bounds(conn, local_date, tz_name)
+    return bounds is not None and bounds[0] <= instant < bounds[1]
+
+
+def _monitoring_period_covers(
+    conn: sqlite3.Connection,
+    start: datetime,
+    end: datetime,
+) -> bool:
+    """Require continuous monitoring before a local-day total replaces detail."""
+    for started_at, ended_at in conn.execute(
+        "SELECT started_at, ended_at FROM monitoring_periods"
+    ):
+        period_start = _parse_sample_time(started_at)
+        period_end = _parse_sample_time(ended_at) if ended_at is not None else None
+        if period_start is None or period_start > start:
+            continue
+        if ended_at is None or (period_end is not None and end <= period_end):
+            return True
+    return False
+
+
+def _has_local_replacement(
+    conn: sqlite3.Connection,
+    previous: tuple,
+    current: tuple,
+    start: datetime,
+    end: datetime,
+) -> bool:
+    start_tz = previous[5]
+    end_tz = current[5]
+    if not end_tz:
+        return False
+
+    start_id, end_id = previous[0], current[0]
+    segment_id = current[2]
+    if (
+        start_tz
+        and start_tz == end_tz
+        and segment_id is not None
+        and _monitoring_period_covers(conn, start, end)
+    ):
+        known_days = conn.execute(
+            "SELECT local_days.utc_start, local_days.utc_end "
+            "FROM local_days JOIN local_day_segment_totals "
+            "  ON local_day_segment_totals.local_day_id = local_days.id "
+            "WHERE local_days.tz_name = ? "
+            "  AND local_days.activity_precision IN ('measured', 'coarse') "
+            "  AND local_days.last_sample_id >= ? "
+            "  AND local_days.activity_intervals > 0 "
+            "  AND local_day_segment_totals.segment_id = ? "
+            "  AND local_day_segment_totals.activity_intervals > 0",
+            (end_tz, end_id, segment_id),
+        ).fetchall()
+        for row in known_days:
+            bounds_start = _parse_sample_time(row[0])
+            bounds_end = _parse_sample_time(row[1])
+            if (
+                bounds_start is not None
+                and bounds_end is not None
+                and bounds_start <= start
+                and end < bounds_end
+            ):
+                return True
+
+    evidence = conn.execute(
+        "SELECT bytes_written, bytes_read, reason, start_local_date, end_local_date, "
+        "       start_tz_name, end_tz_name, started_at, ended_at "
+        "FROM local_day_unallocated_evidence "
+        "WHERE start_sample_id = ? AND end_sample_id = ?",
+        (start_id, end_id),
+    ).fetchone()
+    if evidence is None:
+        return False
+
+    start_written, end_written = previous[3], current[3]
+    start_read, end_read = previous[4], current[4]
+    if None in (start_written, end_written, start_read, end_read):
+        return False
+    if end_written < start_written or end_read < start_read:
+        return False
+    # The source IDs uniquely identify this interval. Confirm its durable
+    # deltas and retain every recorded local-day boundary it touches.
+    if (end_written - start_written, end_read - start_read) != evidence[:2]:
+        return False
+    if evidence[5] != start_tz or evidence[6] != end_tz:
+        return False
+    if evidence[2] not in {
+        "counter_discontinuity",
+        "legacy_timezone_unknown",
+        "timezone_change",
+        "monitoring_period",
+        "local_midnight",
+        "segment_unknown",
+    }:
+        return False
+    if _parse_sample_time(evidence[7]) != start or _parse_sample_time(evidence[8]) != end:
+        return False
+
+    affected_days: set[tuple[str, str]] = set()
+    if start_tz:
+        affected_days.add((evidence[3], start_tz))
+    affected_days.add((evidence[4], end_tz))
+    if start_tz and start_tz == end_tz and evidence[3] < evidence[4]:
+        day = date.fromisoformat(evidence[3]) + timedelta(days=1)
+        last_day = date.fromisoformat(evidence[4])
+        while day < last_day:
+            affected_days.add((day.isoformat(), end_tz))
+            day += timedelta(days=1)
+    if not all(
+        _local_day_row_exists(conn, local_date, zone)
+        for local_date, zone in affected_days
+    ):
+        return False
+    if start_tz and not _contains_instant(conn, evidence[3], start_tz, start):
+        return False
+    return _contains_instant(conn, evidence[4], end_tz, end)
+
+
+def _interval_has_replacement(
+    conn: sqlite3.Connection,
+    previous: tuple,
+    current: tuple,
+) -> bool:
+    start = _parse_sample_time(previous[1])
+    end = _parse_sample_time(current[1])
+    if start is None or end is None or end <= start:
+        return False
+    try:
+        return (
+            _has_utc_replacement(conn, previous, current, start, end)
+            and _has_local_replacement(conn, previous, current, start, end)
+        )
+    except (sqlite3.Error, ValueError, OverflowError, TypeError):
+        # Missing or unreadable derived evidence never authorizes deletion.
+        return False
+
+
+def _sample_needs_preservation(
+    conn: sqlite3.Connection,
+    rows: list[tuple],
+    index: int,
+    newest_id: int,
+) -> bool:
+    sample = rows[index]
+    segment_id = sample[2]
+    if segment_id is None or conn.execute(
+        "SELECT 1 FROM controller_segments WHERE id = ?",
+        (segment_id,),
+    ).fetchone() is None:
+        return True
+    if sample[0] == newest_id:
+        # Keep newest sample as the source anchor for the next collection.
+        return True
+
+    pairs = []
+    if index > 0 and rows[index - 1][2] == segment_id:
+        pairs.append((rows[index - 1], sample))
+    if index + 1 < len(rows) and rows[index + 1][2] == segment_id:
+        pairs.append((sample, rows[index + 1]))
+    return any(
+        not _interval_has_replacement(conn, previous, current)
+        for previous, current in pairs
+    )
+
+
 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 whether an old sample still carries unreplaced evidence."""
+    sample_time = _parse_sample_time(sample_ts)
+    cutoff = _utc_datetime(now) - timedelta(days=RAW_SAMPLE_RETENTION_DAYS)
+    if sample_time is None:
         return True
-            current_hour += timedelta(hours=1)
-        
-        # All hours in the span have observations - interval is derived
+    if sample_time >= cutoff:
         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,),
+
+    rows = _sample_rows(conn)
+    matching = [index for index, row in enumerate(rows) if row[1] == sample_ts]
+    if not matching:
+        return False
+    newest_id = rows[-1][0] if rows else -1
+    return any(
+        _sample_needs_preservation(conn, rows, index, newest_id)
+        for index in matching
     )
-        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(
@@ -127,36 +334,50 @@ def prune_old_samples(
     now: datetime,
     retention_days: int = RAW_SAMPLE_RETENTION_DAYS,
 ) -> int:
-    """Remove raw samples older than retention_days.
+    """Delete expired samples only after every dependent fact is durable.
 
-    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.
+    Pending publications are stored separately and never selected here. A
+    sample stays when it is the newest successor anchor, has an unpublishable
+    neighbour interval, lacks UTC or local-day replacement evidence, or has a
+    timestamp that cannot be safely interpreted.
     """
-    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
+    cutoff = _utc_datetime(now) - timedelta(days=retention_days)
+    owns_transaction = not conn.in_transaction
+    savepoint = "fenris_sample_retention"
+    if owns_transaction:
+        conn.execute("BEGIN IMMEDIATE")
+    else:
+        conn.execute(f"SAVEPOINT {savepoint}")
 
+    try:
+        rows = _sample_rows(conn)
+        if not rows:
+            if owns_transaction:
                 conn.commit()
-    return removed
+            else:
+                conn.execute(f"RELEASE SAVEPOINT {savepoint}")
+            return 0
+
+        newest_id = rows[-1][0]
+        expired = []
+        for index, row in enumerate(rows):
+            sample_time = _parse_sample_time(row[1])
+            if sample_time is None or sample_time >= cutoff:
+                continue
+            if _sample_needs_preservation(conn, rows, index, newest_id):
+                continue
+            expired.append(row[0])
+
+        conn.executemany("DELETE FROM samples WHERE id = ?", ((sample_id,) for sample_id in expired))
+        if owns_transaction:
+            conn.commit()
+        else:
+            conn.execute(f"RELEASE SAVEPOINT {savepoint}")
+        return len(expired)
+    except Exception:
+        if owns_transaction:
+            conn.rollback()
+        else:
+            conn.execute(f"ROLLBACK TO SAVEPOINT {savepoint}")
+            conn.execute(f"RELEASE SAVEPOINT {savepoint}")
+        raise

src/fenris/repair.py

@@ -1,8 +1,9 @@
-"""Historical repair and retention (issue #74).
+"""Historical repair and retention (issue #74, #99).
 
 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.
+rebuilds legacy local-day evidence from surviving samples or trustworthy UTC
+hours, and preserves import markers, boundary anchors, and valid summaries.
+Repair is idempotent and interruption-safe.
 
 Contracts:
 - Idempotent: running repair multiple times produces no duplicates
@@ -71,7 +72,6 @@ def _set_repair_in_progress(conn: sqlite3.Connection, in_progress: bool) -> None
         "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:
@@ -101,8 +101,6 @@ def _update_repair_status(conn: sqlite3.Connection, result: RepairResult) -> Non
         ("days_derived", str(days)),
     )
 
-    conn.commit()
-
 
 def get_repair_status(conn: sqlite3.Connection) -> RepairStatus:
     """Get current repair status for read-only views."""
@@ -364,20 +362,16 @@ def repair_derivation(
     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
+        # A committed in-progress marker may be stale after process death.
+        # SQLite's write lock serializes active repairs; retry idempotently.
+        if conn.in_transaction:
+            conn.commit()
+        conn.execute("BEGIN IMMEDIATE")
+        _set_repair_in_progress(conn, True)
+        conn.commit()
         conn.execute("BEGIN IMMEDIATE")
         
         # 1. Find and derive intervals from sample pairs
@@ -408,6 +402,11 @@ def repair_derivation(
                 else:
                     result.days_updated += 1
 
+        # Rebuild only legacy or unavailable local-day activity. This shares
+        # the migration derivation and leaves trustworthy published totals intact.
+        from .local_day import repair_legacy_local_day_evidence
+        repair_legacy_local_day_evidence(conn)
+
         # 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")
@@ -428,21 +427,22 @@ def repair_derivation(
         )
         result.legacy_summaries_preserved = cursor.fetchone()[0]
         
-        # Commit transaction
+        # Publish derived rows and completion status together. A process
+        # interruption rolls back the in-progress marker with the repair.
+        _update_repair_status(conn, result)
+        _set_repair_in_progress(conn, False)
         conn.commit()
         
-        # Update repair status
-        _update_repair_status(conn, result)
-        
     except Exception as e:
         conn.rollback()
+        try:
+            _set_repair_in_progress(conn, False)
+            conn.commit()
+        except sqlite3.Error:
+            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/status.py

@@ -35,9 +35,9 @@ from .init_system import (
 # Freshness constants (§8.9, §8.2)
 # ---------------------------------------------------------------------------
 
-CADENCE_DEFAULT_S = 300           # 5 min
+CADENCE_DEFAULT_S = 180           # 3 min
 ACCURACY_SEC = 30
-FRESH_THRESHOLD_S = 2 * CADENCE_DEFAULT_S + ACCURACY_SEC + 60  # 690 s
+FRESH_THRESHOLD_S = 2 * CADENCE_DEFAULT_S + ACCURACY_SEC + 60  # 450 s
 STALENESS_THRESHOLD_S = 48 * 3600  # 48 h
 
 

src/fenris/status_composition.py

@@ -115,6 +115,7 @@ class StatusComposition:
     # Sample counts for waiting explanations
     sample_count: int = 0
     day_count: int = 0
+    pending_publication_count: int = 0
 
     # Whether the status dot should blink (only Monitoring)
     should_blink: bool = False
@@ -286,6 +287,7 @@ def compose_status(
     freshness_age_s = None
     sample_count = 0
     day_count = 0
+    pending_publication_count = 0
     deliberately_paused = False
 
     if conn is None and store_fault is None and newer_schema is None:
@@ -315,6 +317,10 @@ def compose_status(
             sample_count = cursor.fetchone()[0]
             cursor = conn.execute("SELECT COUNT(*) FROM day_aggregates")
             day_count = cursor.fetchone()[0]
+            schema_version = conn.execute("PRAGMA user_version").fetchone()[0]
+            if schema_version >= 4:
+                cursor = conn.execute("SELECT COUNT(*) FROM pending_publications")
+                pending_publication_count = cursor.fetchone()[0]
         except sqlite3.Error as exc:
             store_fault = str(exc)
 
@@ -328,6 +334,7 @@ def compose_status(
         freshness = "unknown"
         freshness_age_s = None
         sample_count = day_count = 0
+        pending_publication_count = 0
         deliberately_paused = False
 
     # --- External stop detection ---
@@ -417,6 +424,7 @@ def compose_status(
         overlay_base=overlay_base,
         sample_count=sample_count,
         day_count=day_count,
+        pending_publication_count=pending_publication_count,
         continuity=continuity,
         paused_lines=paused_lines,
     )
@@ -459,6 +467,8 @@ def render_status_cli(comp: StatusComposition) -> str:
     facts.append("timer: %s" % (
         "unknown" if comp.timer_active is None else "active" if comp.timer_active else "inactive"
     ))
+    if comp.pending_publication_count:
+        facts.append(_pending_publication_text(comp.pending_publication_count))
 
     if facts:
         lines.append(" · ".join(facts))
@@ -524,6 +534,8 @@ def render_status_tui(comp: StatusComposition) -> str:
     facts.append("Timer: %s" % (
         "unknown" if comp.timer_active is None else "active" if comp.timer_active else "inactive"
     ))
+    if comp.pending_publication_count:
+        facts.append(_pending_publication_text(comp.pending_publication_count).capitalize())
 
     if facts:
         lines.append(" · ".join(facts))
@@ -539,3 +551,8 @@ def render_status_tui(comp: StatusComposition) -> str:
             lines.append(pl[:1].upper() + pl[1:])
 
     return "\n".join(lines)
+
+
+def _pending_publication_text(count: int) -> str:
+    noun = "observation" if count == 1 else "observations"
+    return f"pending publication: {count} {noun} retained for retry"

src/fenris/store.py

@@ -3,8 +3,7 @@
 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
+- Observation records, derived activity, publication state, and metadata
 """
 import sqlite3
 from pathlib import Path
@@ -12,7 +11,7 @@ from typing import Optional
 
 
 # Schema version - increment on each migration
-SCHEMA_VERSION = 2
+SCHEMA_VERSION = 6
 
 
 # Packaged default placement (spec §8.3). The config may override it, but a
@@ -33,7 +32,7 @@ def get_store_path(config: dict) -> 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.
+    Creates the observation schema, including private pending-publication storage.
     Returns a connection to the store.
     """
     conn = sqlite3.connect(str(store_path))
@@ -73,9 +72,11 @@ def init_store(store_path: Path) -> sqlite3.Connection:
         )
     elif current_version < SCHEMA_VERSION:
         # Older version - apply migrations
+        try:
             _apply_migrations(conn, current_version)
-        conn.execute(f"PRAGMA user_version={SCHEMA_VERSION}")
-        conn.commit()
+        except Exception:
+            conn.close()
+            raise
     
     return conn
 
@@ -107,7 +108,8 @@ def _create_schema(conn: sqlite3.Connection):
             bytes_written INTEGER,
             bytes_read INTEGER,
             critical_warning INTEGER,
-            segment_id INTEGER
+            segment_id INTEGER,
+            local_tz TEXT
         )
     """)
     
@@ -193,6 +195,34 @@ def _create_schema(conn: sqlite3.Connection):
     """)
 
 
+    # Local-day activity summaries derived from UTC hour observations.
+    # Each row retains its recorded timezone and UTC boundaries so that
+    # historical summaries survive a system-timezone change (ADR 0010).
+    conn.execute("""
+        CREATE TABLE IF NOT EXISTS local_days (
+            id INTEGER PRIMARY KEY AUTOINCREMENT,
+            local_date TEXT NOT NULL,     -- e.g. "2026-09-01" in the recorded tz
+            tz_name TEXT NOT NULL,        -- POSIX tz name, e.g. "Asia/Kolkata"
+            tz_offset TEXT NOT NULL,      -- e.g. "+05:30"
+            utc_start TEXT NOT NULL,      -- ISO 8601 UTC: local midnight start
+            utc_end TEXT NOT NULL,        -- ISO 8601 UTC: local midnight end
+            bytes_written INTEGER DEFAULT 0,
+            bytes_read INTEGER DEFAULT 0,
+            coverage REAL DEFAULT 0.0,
+            sample_count INTEGER DEFAULT 0,
+            complete BOOLEAN DEFAULT 0,
+            activity_seconds INTEGER NOT NULL DEFAULT 0,
+            activity_intervals INTEGER NOT NULL DEFAULT 0,
+            activity_incomplete BOOLEAN NOT NULL DEFAULT 0,
+            activity_precision TEXT NOT NULL DEFAULT 'measured',
+            last_sample_id INTEGER,
+            UNIQUE(local_date, tz_name)
+        )
+    """)
+
+    _create_local_day_shared_evidence(conn)
+    _create_local_day_segment_totals(conn)
+
     # Metadata table for store state (e.g., legacy import marker)
     conn.execute("""
         CREATE TABLE IF NOT EXISTS store_metadata (
@@ -201,34 +231,181 @@ def _create_schema(conn: sqlite3.Connection):
         )
     """)
 
+    _create_pending_publications(conn)
+
+
+def _create_pending_publications(conn: sqlite3.Connection) -> None:
+    """Create private staging for valid observations awaiting derivation."""
+    conn.execute("""
+        CREATE TABLE IF NOT EXISTS pending_publications (
+            id INTEGER PRIMARY KEY AUTOINCREMENT,
+            sample_ts TEXT NOT NULL,
+            payload TEXT NOT NULL
+        )
+    """)
+
+
+def _create_local_day_shared_evidence(conn: sqlite3.Connection) -> None:
+    """Create once-only local activity evidence that cannot be day-allocated."""
+    conn.execute("""
+        CREATE TABLE IF NOT EXISTS local_day_unallocated_evidence (
+            id INTEGER PRIMARY KEY AUTOINCREMENT,
+            start_sample_id INTEGER NOT NULL,
+            end_sample_id INTEGER NOT NULL,
+            start_local_date TEXT NOT NULL,
+            end_local_date TEXT NOT NULL,
+            start_tz_name TEXT,
+            end_tz_name TEXT,
+            started_at TEXT NOT NULL,
+            ended_at TEXT NOT NULL,
+            bytes_written INTEGER NOT NULL DEFAULT 0,
+            bytes_read INTEGER NOT NULL DEFAULT 0,
+            reason TEXT NOT NULL,
+            segment_id INTEGER,
+            UNIQUE(start_sample_id, end_sample_id)
+        )
+    """)
+    conn.execute(
+        "CREATE INDEX IF NOT EXISTS local_day_evidence_start "
+        "ON local_day_unallocated_evidence(start_local_date, start_tz_name)"
+    )
+    conn.execute(
+        "CREATE INDEX IF NOT EXISTS local_day_evidence_end "
+        "ON local_day_unallocated_evidence(end_local_date, end_tz_name)"
+    )
+
+
+def _create_local_day_segment_totals(conn: sqlite3.Connection) -> None:
+    """Retain the controller-segment provenance behind known day totals."""
+    conn.execute("""
+        CREATE TABLE IF NOT EXISTS local_day_segment_totals (
+            id INTEGER PRIMARY KEY AUTOINCREMENT,
+            local_day_id INTEGER NOT NULL,
+            segment_id INTEGER NOT NULL,
+            bytes_written INTEGER NOT NULL DEFAULT 0,
+            bytes_read INTEGER NOT NULL DEFAULT 0,
+            activity_seconds INTEGER NOT NULL DEFAULT 0,
+            activity_intervals INTEGER NOT NULL DEFAULT 0,
+            UNIQUE(local_day_id, segment_id)
+        )
+    """)
+
 
 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
+    Commit each version transition independently. A failed step rolls back in
+    full while earlier successful steps remain versioned and retryable.
     """
-    # 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)
+    migrations = {
+        2: _migrate_1_to_2,
+        3: _migrate_2_to_3,
+        4: _migrate_3_to_4,
+        5: _migrate_4_to_5,
+        6: _migrate_5_to_6,
+    }
+    while current_version < SCHEMA_VERSION:
+        target_version = current_version + 1
+        migration = migrations.get(target_version)
+        if migration is None:
+            raise ValueError(f"No migration registered for schema {target_version}")
+        conn.execute("BEGIN IMMEDIATE")
+        try:
+            migration(conn)
+            conn.execute(f"PRAGMA user_version={target_version}")
+            conn.commit()
+        except Exception:
+            conn.rollback()
+            raise
+        current_version = target_version
+
+
+def _migrate_1_to_2(conn: sqlite3.Connection) -> None:
+    """Add segment provenance and unattributed UTC byte tracking."""
     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()}
+        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
+        cols = {row[1] for row in conn.execute(
+            "PRAGMA table_info(day_aggregates)"
+        ).fetchall()}
+        for column in ("unattributed_bytes_written", "unattributed_bytes_read"):
+            if column not in cols:
+                conn.execute(
+                    f"ALTER TABLE day_aggregates ADD COLUMN {column} INTEGER DEFAULT 0"
+                )
+
+
+def _migrate_2_to_3(conn: sqlite3.Connection) -> None:
+    """Add local-day activity summaries."""
+    tables = {row[0] for row in conn.execute(
+        "SELECT name FROM sqlite_master WHERE type='table'"
+    ).fetchall()}
+    if "local_days" not in tables:
+        conn.execute("""
+            CREATE TABLE local_days (
+                id INTEGER PRIMARY KEY AUTOINCREMENT,
+                local_date TEXT NOT NULL,
+                tz_name TEXT NOT NULL,
+                tz_offset TEXT NOT NULL,
+                utc_start TEXT NOT NULL,
+                utc_end TEXT NOT NULL,
+                bytes_written INTEGER DEFAULT 0,
+                bytes_read INTEGER DEFAULT 0,
+                coverage REAL DEFAULT 0.0,
+                sample_count INTEGER DEFAULT 0,
+                complete BOOLEAN DEFAULT 0,
+                UNIQUE(local_date, tz_name)
+            )
+        """)
+
+
+def _migrate_3_to_4(conn: sqlite3.Connection) -> None:
+    """Add private publication staging for acquired observations."""
+    _create_pending_publications(conn)
+
+
+def _migrate_4_to_5(conn: sqlite3.Connection) -> None:
+    """Add measured local-day evidence storage and mark old totals legacy."""
+    tables = {row[0] for row in conn.execute(
+        "SELECT name FROM sqlite_master WHERE type='table'"
+    ).fetchall()}
+    if "samples" in tables:
+        sample_cols = {row[1] for row in conn.execute(
+            "PRAGMA table_info(samples)"
+        ).fetchall()}
+        if "local_tz" not in sample_cols:
+            conn.execute("ALTER TABLE samples ADD COLUMN local_tz TEXT")
+    if "local_days" in tables:
+        local_cols = {row[1] for row in conn.execute(
+            "PRAGMA table_info(local_days)"
+        ).fetchall()}
+        for column, declaration in (
+            ("activity_seconds", "INTEGER NOT NULL DEFAULT 0"),
+            ("activity_intervals", "INTEGER NOT NULL DEFAULT 0"),
+            ("activity_incomplete", "BOOLEAN NOT NULL DEFAULT 0"),
+            ("activity_precision", "TEXT NOT NULL DEFAULT 'legacy'"),
+            ("last_sample_id", "INTEGER"),
+        ):
+            if column not in local_cols:
+                conn.execute(
+                    f"ALTER TABLE local_days ADD COLUMN {column} {declaration}"
+                )
+    _create_local_day_shared_evidence(conn)
+    _create_local_day_segment_totals(conn)
+
+
+def _migrate_5_to_6(conn: sqlite3.Connection) -> None:
+    """Rebuild local-day summaries from surviving trustworthy evidence."""
+    from .local_day import repair_legacy_local_day_evidence
+
+    repair_legacy_local_day_evidence(conn)
 
 
 def migrate_to_latest(store_path: Path) -> int:
@@ -265,9 +442,11 @@ def migrate_to_latest(store_path: Path) -> int:
         return SCHEMA_VERSION
     
     steps = SCHEMA_VERSION - current_version
+    try:
         _apply_migrations(conn, current_version)
-    conn.execute(f"PRAGMA user_version={SCHEMA_VERSION}")
-    conn.commit()
+    except Exception:
+        conn.close()
+        raise
     conn.close()
     return steps
 

src/fenris/themes.py

@@ -1,6 +1,6 @@
 """Fenris theme presets (issue #80).
 
-Three accessible colour presets: Amber (default), Nord, and High Contrast.
+Chalktone-inspired default plus Amber, Nord, and High Contrast.
 Themes style chrome, borders, accents, muted text, and graph roles;
 status semantic colours/glyphs/text always win.
 
@@ -126,7 +126,22 @@ _HIGH_CONTRAST = Theme(
 # Theme registry
 # ---------------------------------------------------------------------------
 
+_CHALKTONE = Theme(
+    name="fenris-chalktone",
+    primary="#abc4b3", secondary="#c9b69a", accent="#dfc49a",
+    warning="#e9bc79", error="#e58d89", success="#acd29c",
+    foreground="#e0d8c5", background="#202426", surface="#202426",
+    panel="#252a2c", boost="#333b3d", dark=True,
+    variables={
+        "graph-allocated": "#abc4b3", "graph-unallocated": "#dfc49a",
+        "graph-gap": "#e58d89", "graph-zero": "#a7b1a9",
+        "graph-partial": "#e9bc79", "graph-selection": "#f3dbb0",
+        "border-default": "#606d6a", "muted-text": "#a7b1a9",
+    },
+)
+
 THEMES = {
+    "chalktone": _CHALKTONE,
     "amber": _AMBER,
     "nord": _NORD,
     "high_contrast": _HIGH_CONTRAST,
@@ -138,16 +153,16 @@ THEME_NAMES = set(THEMES.keys())
 def get_theme(name: str) -> Theme:
     """Return a registered theme by preset name.
 
-    Unknown names fall back to Amber.
+    Unknown names fall back to Chalktone.
     """
-    return THEMES.get(name, _AMBER)
+    return THEMES.get(name, _CHALKTONE)
 
 
 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.
+    selection and muted text. Falls back to Chalktone for unknown names.
     """
     theme = get_theme(theme_name)
     variables = theme.variables or {}
@@ -158,4 +173,5 @@ def get_graph_colors(theme_name: str) -> Dict[str, str]:
         "zero": variables.get("graph-zero", "#665533"),
         "partial": variables.get("graph-partial", "#aa8822"),
         "selection": variables.get("graph-selection", "#ffd54f"),
+        "muted": variables.get("muted-text", "#a7b1a9"),
     }

src/fenris/tz_util.py

@@ -0,0 +1,52 @@
+"""System timezone detection for local-day activity totals.
+
+Provides timezone detection (TZ env, /etc/localtime) and offset
+computation used by local-day derivation. All functions are
+stateless and safe to call from the collector and TUI reader.
+"""
+import os
+from datetime import datetime, timezone
+from pathlib import Path
+
+
+def detect_system_tz() -> str:
+    """Detect the system timezone name.
+
+    Resolution order:
+    1. ``TZ`` environment variable (may be empty or ":UTC")
+    2. Symlink target of ``/etc/localtime``
+    3. Falls back to ``"UTC"``
+
+    Returns a POSIX timezone name like ``"Asia/Kolkata"`` or ``"UTC"``.
+    """
+    tz = os.environ.get("TZ", "").strip()
+    if tz:
+        return tz.lstrip(":")
+
+    localtime = Path("/etc/localtime")
+    if localtime.is_symlink():
+        target_path = Path(os.readlink(str(localtime)))
+        if not target_path.is_absolute():
+            target_path = localtime.parent / target_path
+        target = target_path.resolve().as_posix()
+        marker = "/zoneinfo/"
+        marker_index = target.find(marker)
+        if marker_index >= 0:
+            return target[marker_index + len(marker):]
+        return target
+
+    return "UTC"
+
+
+def get_tz_offset_str(dt: datetime, tz_name: str) -> str:
+    """UTC offset as ``+HH:MM`` or ``-HH:MM`` string for *dt* in *tz_name*."""
+    from zoneinfo import ZoneInfo
+    local_tz = ZoneInfo(tz_name)
+    local_dt = dt.astimezone(local_tz)
+    offset = local_dt.utcoffset()
+    total_seconds = int(offset.total_seconds())
+    sign = "+" if total_seconds >= 0 else "-"
+    total_seconds = abs(total_seconds)
+    hours = total_seconds // 3600
+    minutes = (total_seconds % 3600) // 60
+    return "%s%02d:%02d" % (sign, hours, minutes)

tests/test_acceptance_sweep.py

@@ -109,12 +109,40 @@ def _open_period(conn, start="2026-09-01T00:00:00+00:00"):
     ensure_period_open(conn, datetime.fromisoformat(start))
 
 
+def _insert_local_day(conn, local_date, tz_name="UTC", tz_offset="+00:00",
+                       utc_start=None, utc_end=None, bw=1024*1024*100,
+                       br=0, coverage=0.95, samples=24, complete=True):
+    """Insert a local_days row (issue #94 gate prerequisite)."""
+    if utc_start is None:
+        utc_start = local_date + "T00:00:00+00:00"
+    if utc_end is None:
+        dt = datetime.strptime(local_date, "%Y-%m-%d") + timedelta(days=1)
+        utc_end = dt.strftime("%Y-%m-%dT00:00:00+00:00")
+    conn.execute(
+        "INSERT INTO local_days "
+        "(local_date, tz_name, tz_offset, utc_start, utc_end, "
+        " bytes_written, bytes_read, coverage, sample_count, complete, activity_intervals) "
+        "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, 1)",
+        (local_date, tz_name, tz_offset, utc_start, utc_end,
+         bw, br, coverage, samples, complete),
+    )
+    conn.commit()
+
+
+def _insert_complete_local_days(conn, start_date, count, bw=1024*1024*100):
+    """Insert multiple complete local days to satisfy the issue #94 gate."""
+    for i in range(count):
+        d = (datetime.strptime(start_date, "%Y-%m-%d") + timedelta(days=i)).strftime("%Y-%m-%d")
+        _insert_local_day(conn, d, bw=bw)
+
+
 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):
+                       baseline_kw=None, segment_kw=None,
+                       local_days=True):
     if baseline:
         _insert_baseline(conn, **(baseline_kw or {}))
     if segment:
@@ -125,6 +153,9 @@ def _setup_full_store(conn, *, baseline=True, segment=True, days=30,
         _insert_day(conn, d, bw=bw, coverage=coverage, samples=samples_per_day)
     if sample_ts:
         _insert_sample(conn, sample_ts)
+    # Issue #94: satisfy the complete-observation-day gate
+    if local_days and days > 0:
+        _insert_complete_local_days(conn, "2026-09-29", 1, bw=bw)
 
 
 # ===================================================================
@@ -217,6 +248,7 @@ class TestCI1StateMatrix:
             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")
+        _insert_complete_local_days(conn, "2026-09-29", 1)
         proj = compute_projection(conn, _clock())
         assert proj.confidence_state == ConfidenceState.LIMITED
         conn.close()
@@ -230,6 +262,7 @@ class TestCI1StateMatrix:
             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")
+        _insert_complete_local_days(conn, "2026-09-29", 1)
         proj = compute_projection(conn, _clock())
         assert proj.confidence_state == ConfidenceState.LIMITED
         assert proj.warming_fact is not None
@@ -245,6 +278,7 @@ class TestCI1StateMatrix:
             _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)
+        _insert_complete_local_days(conn, "2026-08-30", 1)
         proj = compute_projection(conn, _clock())
         assert proj.confidence_state == ConfidenceState.LIMITED
         assert proj.staleness_fact is not None
@@ -259,6 +293,7 @@ class TestCI1StateMatrix:
             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")
+        _insert_complete_local_days(conn, "2026-09-29", 1)
         proj = compute_projection(conn, _clock())
         assert proj.confidence_state == ConfidenceState.LIMITED
         assert proj.degraded_identity_fact is not None
@@ -273,6 +308,7 @@ class TestCI1StateMatrix:
             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")
+        _insert_complete_local_days(conn, "2026-09-29", 1)
         proj = compute_projection(conn, _clock())
         assert proj.confidence_state == ConfidenceState.UNSUPPORTED
         assert proj.zero_rate_fact is not None

tests/test_activity_plot.py

@@ -0,0 +1,52 @@
+"""Visible geometry and evidence boundaries of the terminal volume plot."""
+from fenris.activity_plot import VolumePoint, volume_plot
+from fenris.themes import get_graph_colors
+
+
+def plot(points, selected=-1, width=48, height=10):
+    return volume_plot(points, width, height, selected, get_graph_colors("chalktone"))
+
+
+def test_trace_fits_viewport_and_uses_time_not_sample_index():
+    points = [VolumePoint(t, v, str(t)) for t, v in ((0, 0), (3, 50), (30, 100))]
+    text, columns, unit = plot(points)
+    assert unit == "B"
+    assert len(text.plain.splitlines()) == 10
+    assert all(len(line) <= 48 for line in text.plain.splitlines())
+    assert columns[1] - columns[0] < (columns[2] - columns[0]) / 5
+    assert any(0x2801 <= ord(c) <= 0x28ff for c in text.plain)
+    assert not any(c in text.plain for c in "█▒░")
+    assert "100.00" in text.plain and "0.00" in text.plain
+
+
+def test_gap_breaks_trace_while_measured_zero_stays_on_axis():
+    text, columns, _ = plot([
+        VolumePoint(0, 0, "00:00"), VolumePoint(1, None, "00:03", "gap"),
+        VolumePoint(2, 100, "00:06"),
+    ])
+    rows = text.plain.splitlines()
+    assert "?" in rows[-2]
+    # No invented intermediate dots on either side of the missing measurement.
+    for row in rows[:-2]:
+        assert all(c == " " for c in row[columns[0] + 1:columns[-1]])
+    assert 0x2801 <= ord(rows[-3][columns[0]]) <= 0x28ff
+
+
+def test_partial_and_unallocated_totals_are_isolated_and_labelled():
+    text, columns, unit = plot([
+        VolumePoint(0, 1_000_000, "01", "partial"),
+        VolumePoint(1, 2_000_000, "02", "unallocated"),
+        VolumePoint(2, 3_000_000, "03"),
+    ])
+    assert unit == "MB"
+    assert "~" in text.plain and "u" in text.plain
+    for row in text.plain.splitlines()[:-2]:
+        assert all(c == " " for c in row[columns[0] + 1:columns[1]])
+
+
+def test_many_intervals_and_selection_fit_small_plot_without_losing_points():
+    points = [VolumePoint(i, i % 9 * 1_000_000, str(i)) for i in range(180)]
+    text, columns, _ = plot(points, selected=100, width=32, height=6)
+    assert len(columns) == len(points)
+    assert text.plain.splitlines()[-2][columns[100]] == "▼"
+    assert all(len(row) == 32 for row in text.plain.splitlines())

tests/test_activity_selection.py

@@ -0,0 +1,94 @@
+"""Activity-selection transitions independent from Textual widgets."""
+import sys
+from pathlib import Path
+
+sys.path.insert(0, str(Path(__file__).parent.parent / "src"))
+
+from fenris.activity_selection import ActivitySelection, IntervalIdentity
+
+
+def _interval(n):
+    return IntervalIdentity(f"start-{n}", f"end-{n}")
+
+
+def test_live_selection_starts_and_stays_on_newest_interval():
+    selection = ActivitySelection()
+    first = [_interval(1), _interval(2)]
+
+    selection.update_live(first)
+    assert selection.following_live
+    assert selection.selected_live_interval == first[-1]
+
+    second = first + [_interval(3)]
+    selection.update_live(second)
+    assert selection.selected_live_interval == second[-1]
+
+
+def test_keyboard_and_mouse_inspection_pin_interval_identity():
+    intervals = [_interval(1), _interval(2), _interval(3)]
+    keyboard = ActivitySelection()
+    mouse = ActivitySelection()
+
+    keyboard.update_live(intervals)
+    keyboard.move_live(intervals, -1)
+    mouse.update_live(intervals)
+    mouse.inspect_live(intervals, intervals[1])
+
+    assert keyboard.selected_live_interval == mouse.selected_live_interval == intervals[1]
+    assert not keyboard.following_live
+    assert not mouse.following_live
+
+    refreshed = [_interval(2), _interval(3), _interval(4)]
+    keyboard.update_live(refreshed)
+    mouse.update_live(refreshed)
+    assert keyboard.selected_live_interval == mouse.selected_live_interval == intervals[1]
+
+
+def test_expired_pin_explains_expiration_and_resumes_following():
+    selection = ActivitySelection()
+    intervals = [_interval(1), _interval(2), _interval(3)]
+    selection.update_live(intervals)
+    selection.inspect_live(intervals, intervals[0])
+
+    newest = _interval(4)
+    selection.update_live([_interval(2), _interval(3), newest])
+
+    assert selection.following_live
+    assert selection.selected_live_interval == newest
+    assert selection.live_interval_expired
+
+
+def test_today_resets_expired_pin_and_read_write_toggle_keeps_identity():
+    selection = ActivitySelection()
+    intervals = [_interval(1), _interval(2)]
+    selection.update_live(intervals)
+    selection.inspect_live(intervals, intervals[0])
+    selection.update_live([intervals[1]])
+    newest = _interval(3)
+    selection.update_live([intervals[1], newest])
+    assert selection.live_interval_expired
+
+    selection.toggle_measure()
+    assert selection.measure == "read"
+    assert selection.selected_live_interval == newest
+
+    selection.select_history_date("2026-09-27")
+    selection.set_view("history")
+    selection.set_view("live")
+    assert selection.browse_date is None
+    assert selection.following_live
+    assert not selection.live_interval_expired
+
+
+def test_live_identity_uses_both_interval_boundaries():
+    first = IntervalIdentity("2026-09-28T10:00:00Z", "2026-09-28T10:03:00Z")
+    changed_start = IntervalIdentity("2026-09-28T09:57:00Z", "2026-09-28T10:03:00Z")
+    selection = ActivitySelection()
+    selection.update_live([first])
+    selection.inspect_live([first], first)
+
+    selection.update_live([changed_start])
+
+    assert selection.following_live
+    assert selection.selected_live_interval == changed_start
+    assert selection.live_interval_expired

tests/test_changelog.py

@@ -79,6 +79,20 @@ def test_release_footer_verifies_the_clearsigned_checksum_asset():
     assert "sha256sum -c SHA256SUMS" in footer
 
 
+def test_release_footer_configures_the_xbps_url_as_a_repository():
+    footer = (REPO_ROOT / "packaging" / "release-footer.md").read_text(
+        encoding="utf-8"
+    )
+
+    repository = (
+        "repository=https://git.bongbetic.com/xavierk/Fenris-xbps/"
+        "raw/branch/stable/x86_64"
+    )
+    assert repository in footer
+    assert "sudo xbps-install -M -S fenris" in footer
+    assert "sudo xbps-install -S https://git.bongbetic.com" not in footer
+
+
 @pytest.mark.parametrize(
     ("changelog", "expected_error"),
     [

tests/test_collector_history_tracer.py

@@ -154,7 +154,7 @@ class TestSchemaMigration:
 
         # Migrate
         steps = migrate_to_latest(db)
-        assert steps == 1
+        assert steps == 5  # v1→v2→v3→v4→v5→v6
 
         # Verify data preserved
         conn = sqlite3.connect(str(db))
@@ -356,6 +356,167 @@ class TestCollectorDerivation:
         assert count_after == 2
 
 
+class TestCollectionAtomicity:
+    """Collection exposes sample and derived evidence as one publication."""
+
+    @pytest.mark.asyncio
+    async def test_collection_is_visible_through_cli_and_tui_readers(
+        self, config_fixture, smartctl_fixture, sysfs_fixture_tree, monkeypatch
+    ):
+        """Ordinary readers observe matching published sample and activity evidence."""
+        from fenris.status import get_status, read_status
+        from fenris.tui import FenrisTuiApp
+
+        monkeypatch.setenv("TZ", "UTC")
+        service = {
+            "boot_enabled": True,
+            "timer_active": True,
+            "last_collect_ok": True,
+        }
+        monkeypatch.setattr("fenris.status.query_service_state", lambda: service)
+
+        now = datetime.now(timezone.utc).replace(
+            minute=35, second=0, microsecond=0,
+        )
+        first = {
+            **smartctl_fixture,
+            "nvme_smart_health_information_log": {
+                **smartctl_fixture["nvme_smart_health_information_log"],
+                "data_units_written": 12345678,
+                "data_units_read": 9876543,
+            },
+        }
+        second = {
+            **smartctl_fixture,
+            "nvme_smart_health_information_log": {
+                **smartctl_fixture["nvme_smart_health_information_log"],
+                "data_units_written": 12345698,
+                "data_units_read": 9876553,
+            },
+        }
+        sysfs_path = sysfs_fixture_tree / "sys" / "class" / "nvme" / "nvme0"
+
+        assert run_collection(
+            first, sysfs_path, config_fixture, FakeClock(now - timedelta(minutes=5))
+        )["ok"] is True
+        assert run_collection(
+            second, sysfs_path, config_fixture, FakeClock(now)
+        )["ok"] is True
+
+        store_path = Path(config_fixture["store_path"])
+        with read_status(store_path, now, query_services=False) as (reader, composition):
+            assert reader is not None
+            assert composition.sample_count == 2
+            assert composition.day_count == 1
+            utc_day = reader.execute(
+                "SELECT bytes_written_delta, bytes_read_delta FROM day_aggregates"
+            ).fetchone()
+            local_day = reader.execute(
+                "SELECT bytes_written, bytes_read FROM local_days"
+            ).fetchone()
+            assert tuple(utc_day) == (10_240_000, 5_120_000)
+            assert tuple(local_day) == (10_240_000, 5_120_000)
+
+        cli_output = get_status(
+            store_path, now, query_services=True, query_journal=False
+        )
+        assert "Monitoring" in cli_output
+
+        app = FenrisTuiApp(store_path=store_path)
+        async with app.run_test(size=(100, 30)) as pilot:
+            await pilot.pause()
+            live_readout = str(app.query_one("#live-readout").render())
+            assert "W 0.010 GB" in live_readout
+            assert "R 0.005 GB" in live_readout
+
+        repeated_result = run_collection(
+            second, sysfs_path, config_fixture, FakeClock(now + timedelta(minutes=5))
+        )
+        assert repeated_result["ok"] is True
+        with read_status(
+            store_path, now + timedelta(minutes=5), query_services=False
+        ) as (reader, composition):
+            assert reader is not None
+            assert composition.sample_count == 3
+            utc_day = reader.execute(
+                "SELECT bytes_written_delta, bytes_read_delta FROM day_aggregates"
+            ).fetchone()
+            local_day = reader.execute(
+                "SELECT bytes_written, bytes_read FROM local_days"
+            ).fetchone()
+            assert tuple(utc_day) == (10_240_000, 5_120_000)
+            assert tuple(local_day) == (10_240_000, 5_120_000)
+
+    def test_failed_local_day_publication_keeps_previous_publication(
+        self, config_fixture, smartctl_fixture, sysfs_fixture_tree, monkeypatch
+    ):
+        """A failed final derivation step leaves all prior reader state intact."""
+        from fenris.status import read_status
+
+        monkeypatch.setenv("TZ", "UTC")
+        now = datetime.now(timezone.utc).replace(second=0, microsecond=0)
+        first_clock = FakeClock(now)
+        first = {
+            **smartctl_fixture,
+            "nvme_smart_health_information_log": {
+                **smartctl_fixture["nvme_smart_health_information_log"],
+                "data_units_written": 12345678,
+                "data_units_read": 9876543,
+            },
+        }
+        first_result = run_collection(
+            first,
+            sysfs_fixture_tree / "sys" / "class" / "nvme" / "nvme0",
+            config_fixture,
+            first_clock,
+        )
+        assert first_result["ok"] is True, first_result
+
+        writer = sqlite3.connect(config_fixture["store_path"])
+        writer.execute(
+            "CREATE TRIGGER fail_local_day_publication "
+            "BEFORE INSERT ON local_days "
+            "BEGIN SELECT RAISE(ABORT, 'injected local-day publication failure'); END"
+        )
+        writer.commit()
+        writer.close()
+
+        next_time = now + timedelta(minutes=5)
+        second = {
+            **smartctl_fixture,
+            "nvme_smart_health_information_log": {
+                **smartctl_fixture["nvme_smart_health_information_log"],
+                "data_units_written": 12345698,
+                "data_units_read": 9876548,
+            },
+        }
+        failed_result = run_collection(
+            second,
+            sysfs_fixture_tree / "sys" / "class" / "nvme" / "nvme0",
+            config_fixture,
+            FakeClock(next_time),
+        )
+
+        assert failed_result["ok"] is False
+        assert "injected local-day publication failure" in failed_result["error"]
+
+        with read_status(
+            Path(config_fixture["store_path"]), next_time, query_services=False
+        ) as (reader, composition):
+            assert reader is not None
+            assert composition.sample_count == 1
+            public_counts = reader.execute(
+                "SELECT (SELECT COUNT(*) FROM samples), "
+                "(SELECT COUNT(*) FROM controller_segments), "
+                "(SELECT COUNT(*) FROM monitoring_periods), "
+                "(SELECT COUNT(*) FROM hour_observations), "
+                "(SELECT COUNT(*) FROM day_aggregates), "
+                "(SELECT COUNT(*) FROM local_days)"
+            ).fetchone()
+
+        assert tuple(public_counts) == (1, 1, 1, 0, 0, 0)
+
+
 # ---------------------------------------------------------------------------
 # Display states: awaiting first sample, awaiting another sample
 # ---------------------------------------------------------------------------

tests/test_collector_tracer.py

@@ -232,7 +232,7 @@ def test_store_initialization(config_fixture: Dict[str, Any]):
     # Initialize store
     conn = init_store(store_path)
     
-    # Verify all six entities exist
+    # Verify the observation, derived-history, and metadata tables exist.
     cursor = conn.execute("SELECT name FROM sqlite_master WHERE type='table'")
     tables = {row[0] for row in cursor.fetchall()}
     
@@ -248,6 +248,10 @@ def test_store_initialization(config_fixture: Dict[str, Any]):
     # sqlite_sequence is a system table created by AUTOINCREMENT
     expected_tables.add("sqlite_sequence")
     expected_tables.add("store_metadata")
+    expected_tables.add("local_days")
+    expected_tables.add("pending_publications")
+    expected_tables.add("local_day_unallocated_evidence")
+    expected_tables.add("local_day_segment_totals")
     assert expected_tables == tables
     
     conn.close()

tests/test_complete_observation_day_gate.py

@@ -0,0 +1,299 @@
+"""Complete observation day gate tests (issue #94).
+
+Verifies that the endurance projection is withheld until at least one
+complete local calendar day has been observed within a monitoring period.
+
+Seams:
+- compute_projection() → gate check via local_days table
+- ProjectionResult.contributing_facts → "waiting for a full local observation day"
+
+Acceptance criteria:
+- Gate-1: No complete local day → UNSUPPORTED with waiting fact
+- Gate-2: One complete local day → Limited confidence (if other conditions met)
+- Gate-3: Partial days don't satisfy the gate
+- Gate-4: CLI and TUI share the same gate via compute_projection()
+"""
+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
+from fenris.projection import (
+    compute_projection, ConfidenceState, BaselineTier,
+    WARMING_COVERAGE_FLOOR,
+)
+
+
+@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):
+    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",
+         "Samsung SSD 970 EVO Plus 1TB", 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"):
+    conn.execute(
+        "INSERT INTO controller_segments "
+        "(opened_at, identity_key, identity_degraded, subnqn, sn, mn, fr, vid, ssvid, transport) "
+        "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)",
+        (opened_at, "nqn.test", False, "nqn.test", "SN123",
+         "Samsung SSD 970 EVO Plus 1TB", "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 _insert_local_day(conn, local_date, tz_name="UTC", tz_offset="+00:00",
+                       utc_start=None, utc_end=None, bw=1024*1024*100,
+                       br=0, coverage=0.95, samples=24, complete=True):
+    """Insert a local_days row for testing the gate."""
+    if utc_start is None:
+        utc_start = local_date + "T00:00:00+00:00"
+    if utc_end is None:
+        # Next day
+        dt = datetime.strptime(local_date, "%Y-%m-%d") + timedelta(days=1)
+        utc_end = dt.strftime("%Y-%m-%dT00:00:00+00:00")
+    conn.execute(
+        "INSERT INTO local_days "
+        "(local_date, tz_name, tz_offset, utc_start, utc_end, "
+        " bytes_written, bytes_read, coverage, sample_count, complete, activity_intervals) "
+        "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, 1)",
+        (local_date, tz_name, tz_offset, utc_start, utc_end,
+         bw, br, coverage, samples, complete),
+    )
+    conn.commit()
+
+
+def _open_period(conn, start="2026-09-01T00:00:00+00:00"):
+    ensure_period_open(conn, datetime.fromisoformat(start))
+
+
+# ---------------------------------------------------------------------------
+# Gate-1: No complete local day → UNSUPPORTED with waiting fact
+# ---------------------------------------------------------------------------
+
+class TestGateNoCompleteDay:
+    """Projection is unavailable before any complete local observation day."""
+
+    def test_no_local_days_unsupported(self, store):
+        """With no local_days entries, projection is UNSUPPORTED."""
+        _insert_baseline(store)
+        _insert_segment(store)
+        _open_period(store)
+        # 14 days of UTC data — enough for normal projection, but no local_days
+        for i in range(14):
+            d = (datetime(2026, 9, 15) + timedelta(days=i)).strftime("%Y-%m-%d")
+            _insert_day(store, d, bw=1024*1024*100)
+        _insert_sample(store, "2026-09-30T10:00:00+00:00", pu=5)
+        result = compute_projection(store, _clock())
+        assert result.confidence_state == ConfidenceState.UNSUPPORTED
+        assert any("full local observation day" in f for f in result.contributing_facts)
+        assert result.headline_remaining_seconds is None
+
+    def test_only_partial_local_days_unsupported(self, store):
+        """Partial (incomplete) local days don't satisfy the gate."""
+        _insert_baseline(store)
+        _insert_segment(store)
+        _open_period(store)
+        for i in range(14):
+            d = (datetime(2026, 9, 15) + timedelta(days=i)).strftime("%Y-%m-%d")
+            _insert_day(store, d, bw=1024*1024*100)
+        _insert_sample(store, "2026-09-30T10:00:00+00:00", pu=5)
+        # Insert only incomplete local days
+        for i in range(5):
+            d = (datetime(2026, 9, 25) + timedelta(days=i)).strftime("%Y-%m-%d")
+            _insert_local_day(store, d, complete=False, coverage=0.3)
+        result = compute_projection(store, _clock())
+        assert result.confidence_state == ConfidenceState.UNSUPPORTED
+        assert any("full local observation day" in f for f in result.contributing_facts)
+
+    def test_gate_before_warming_check(self, store):
+        """Gate fires even when warming would also block — gate has precedence."""
+        _insert_baseline(store)
+        _insert_segment(store)
+        _open_period(store)
+        # Only 3 days of data (below warming threshold)
+        for i in range(3):
+            d = (datetime(2026, 9, 27) + timedelta(days=i)).strftime("%Y-%m-%d")
+            _insert_day(store, d, bw=1024*1024*100)
+        _insert_sample(store, "2026-09-30T10:00:00+00:00", pu=5)
+        # Insert one complete local day — but still below warming
+        _insert_local_day(store, "2026-09-29", complete=True)
+        result = compute_projection(store, _clock())
+        # Gate is satisfied (one complete day), but warming blocks Supported
+        # The key assertion: gate message should NOT appear when gate IS met
+        assert not any("full local observation day" in f for f in result.contributing_facts)
+
+    def test_complete_legacy_day_without_trusted_activity_does_not_open_gate(
+        self, store,
+    ):
+        """A complete flag cannot make unavailable local activity qualify."""
+        _insert_baseline(store)
+        _insert_segment(store)
+        _open_period(store)
+        for i in range(3):
+            day = (datetime(2026, 9, 27) + timedelta(days=i)).strftime("%Y-%m-%d")
+            _insert_day(store, day, bw=1024 * 1024 * 100)
+        _insert_sample(store, "2026-09-30T10:00:00+00:00", pu=5)
+        _insert_local_day(store, "2026-09-29", complete=True)
+        store.execute(
+            "UPDATE local_days SET activity_precision = 'measured', activity_intervals = 0 "
+            "WHERE local_date = '2026-09-29'"
+        )
+        result = compute_projection(store, _clock())
+        assert result.confidence_state == ConfidenceState.UNSUPPORTED
+        assert any("full local observation day" in fact
+                   for fact in result.contributing_facts)
+
+    def test_partial_but_trusted_local_activity_opens_gate(self, store):
+        """Known local intervals can coexist with an incomplete day total."""
+        _insert_baseline(store)
+        _insert_segment(store)
+        _open_period(store)
+        for i in range(3):
+            day = (datetime(2026, 9, 27) + timedelta(days=i)).strftime("%Y-%m-%d")
+            _insert_day(store, day, bw=1024 * 1024 * 100)
+        _insert_sample(store, "2026-09-30T10:00:00+00:00", pu=5)
+        _insert_local_day(store, "2026-09-29", complete=True)
+        store.execute(
+            "UPDATE local_days SET activity_incomplete = 1 "
+            "WHERE local_date = '2026-09-29'"
+        )
+
+        result = compute_projection(store, _clock())
+
+        assert not any("full local observation day" in fact
+                       for fact in result.contributing_facts)
+
+
+# ---------------------------------------------------------------------------
+# Gate-2: One complete local day → Limited confidence
+# ---------------------------------------------------------------------------
+
+class TestGateOneCompleteDay:
+    """After one complete local day, projection can proceed with Limited confidence."""
+
+    def test_one_complete_day_allows_projection(self, store):
+        """With one complete local day and valid baseline/rate, projection is Limited."""
+        _insert_baseline(store, tbw_tb=1.0, verified=True)
+        _insert_segment(store)
+        _open_period(store)
+        # 14 days of UTC data
+        for i in range(14):
+            d = (datetime(2026, 9, 15) + timedelta(days=i)).strftime("%Y-%m-%d")
+            _insert_day(store, d, bw=1024*1024*100)
+        _insert_sample(store, "2026-09-30T10:00:00+00:00", pu=5)
+        # One complete local day
+        _insert_local_day(store, "2026-09-29", complete=True)
+        result = compute_projection(store, _clock())
+        # Gate satisfied — no "waiting" fact
+        assert not any("full local observation day" in f for f in result.contributing_facts)
+        # With only 14 days and other Limited factors, should be Limited or Supported
+        assert result.confidence_state in (ConfidenceState.LIMITED, ConfidenceState.SUPPORTED)
+        # Headline should exist (rate > 0, baseline exists)
+        assert result.headline_remaining_seconds is not None
+
+    def test_gate_fact_absent_when_satisfied(self, store):
+        """The 'waiting for full day' fact does not appear when gate is met."""
+        _insert_baseline(store)
+        _insert_segment(store)
+        _open_period(store)
+        for i in range(20):
+            d = (datetime(2026, 9, 10) + timedelta(days=i)).strftime("%Y-%m-%d")
+            _insert_day(store, d, bw=1024*1024*100)
+        _insert_sample(store, "2026-09-30T10:00:00+00:00", pu=5)
+        _insert_local_day(store, "2026-09-29", complete=True)
+        result = compute_projection(store, _clock())
+        assert not any("full local observation day" in f for f in result.contributing_facts)
+        assert result.confidence_state != ConfidenceState.UNSUPPORTED
+
+
+# ---------------------------------------------------------------------------
+# Gate-3: Partial first day doesn't satisfy the gate
+# ---------------------------------------------------------------------------
+
+class TestGatePartialFirstDay:
+    """Starting monitoring at noon means the partial first day doesn't count."""
+
+    def test_partial_first_day_not_enough(self, store):
+        """A single incomplete local day (started at noon) doesn't open the gate."""
+        _insert_baseline(store)
+        _insert_segment(store, opened_at="2026-09-29T12:00:00+00:00")
+        _open_period(store, start="2026-09-29T12:00:00+00:00")
+        # Only Sep 29 (partial) and Sep 30 (today, partial)
+        _insert_day(store, "2026-09-29", bw=1024*1024*100, coverage=0.5, samples=12)
+        _insert_day(store, "2026-09-30", bw=1024*1024*100, coverage=0.5, samples=12)
+        _insert_sample(store, "2026-09-30T10:00:00+00:00", pu=5)
+        # Only partial local days
+        _insert_local_day(store, "2026-09-29", complete=False, coverage=0.5)
+        _insert_local_day(store, "2026-09-30", complete=False, coverage=0.5)
+        result = compute_projection(store, _clock())
+        assert result.confidence_state == ConfidenceState.UNSUPPORTED
+        assert any("full local observation day" in f for f in result.contributing_facts)
+
+
+# ---------------------------------------------------------------------------
+# Gate-4: Multiple complete days also satisfy the gate
+# ---------------------------------------------------------------------------
+
+class TestGateMultipleCompleteDays:
+    """Multiple complete local days satisfy the gate."""
+
+    def test_multiple_complete_days_satisfy_gate(self, store):
+        """Several complete local days open the gate."""
+        _insert_baseline(store)
+        _insert_segment(store)
+        _open_period(store)
+        for i in range(14):
+            d = (datetime(2026, 9, 15) + timedelta(days=i)).strftime("%Y-%m-%d")
+            _insert_day(store, d, bw=1024*1024*100)
+        _insert_sample(store, "2026-09-30T10:00:00+00:00", pu=5)
+        # 7 complete local days
+        for i in range(7):
+            d = (datetime(2026, 9, 23) + timedelta(days=i)).strftime("%Y-%m-%d")
+            _insert_local_day(store, d, complete=True)
+        result = compute_projection(store, _clock())
+        assert not any("full local observation day" in f for f in result.contributing_facts)
+        assert result.headline_remaining_seconds is not None

tests/test_cross_day_duplication.py

@@ -0,0 +1,145 @@
+"""Cross-day interval unattributed-byte preservation (issue #88).
+
+Verifies that a cross-hour interval spanning midnight is stored ONCE as
+shared boundary evidence, not duplicated into both days.
+
+Seam: derive._add_unattributed_bytes() → day_aggregates.unattributed_bytes_*
+"""
+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.collector import run_collection
+from fenris.store import init_store
+from fenris.monitoring_periods import ensure_period_open
+
+
+def _make_smartctl(duw: int, dur: int):
+    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,
+            "data_units_read": dur, "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_tree(tmp_path: Path) -> Path:
+    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
+
+
+class _Clock:
+    def __init__(self, initial):
+        self.now = initial
+    def utcnow(self):
+        return self.now
+
+
+class TestCrossDayUnattributedNoDuplication:
+    """Unattributed bytes from a midnight-spanning interval must be stored
+    once, not duplicated into both days (issue #88)."""
+
+    def test_midnight_spanning_interval_not_duplicated(
+        self, tmp_path, sysfs_tree,
+    ):
+        """Two samples spanning midnight: 23:55 UTC day1 → 00:05 UTC day2.
+
+        The unattributed bytes should appear once, not in both days.
+        """
+        store = str(tmp_path / "obs.db")
+        cfg = {"device": "/dev/nvme0", "store_path": store}
+        sysfs_nvme = sysfs_tree / "sys" / "class" / "nvme" / "nvme0"
+
+        t1 = datetime(2026, 9, 1, 23, 55, 0, tzinfo=timezone.utc)
+        t2 = datetime(2026, 9, 2, 0, 5, 0, tzinfo=timezone.utc)
+
+        # +100 DUW, +60 DUR across midnight
+        r1 = run_collection(_make_smartctl(10000000, 8000000), sysfs_nvme, cfg, _Clock(t1))
+        assert r1["ok"]
+        r2 = run_collection(_make_smartctl(10000100, 8000060), sysfs_nvme, cfg, _Clock(t2))
+        assert r2["ok"]
+
+        conn = sqlite3.connect(store)
+
+        # Get unattributed bytes for each day
+        unattr_w_day1 = conn.execute(
+            "SELECT unattributed_bytes_written FROM day_aggregates WHERE day = ?",
+            ("2026-09-01",)
+        ).fetchone()
+        unattr_w_day2 = conn.execute(
+            "SELECT unattributed_bytes_written FROM day_aggregates WHERE day = ?",
+            ("2026-09-02",)
+        ).fetchone()
+        unattr_r_day1 = conn.execute(
+            "SELECT unattributed_bytes_read FROM day_aggregates WHERE day = ?",
+            ("2026-09-01",)
+        ).fetchone()
+        unattr_r_day2 = conn.execute(
+            "SELECT unattributed_bytes_read FROM day_aggregates WHERE day = ?",
+            ("2026-09-02",)
+        ).fetchone()
+
+        expected_bw = 100 * 512000  # 51200000
+        expected_br = 60 * 512000   # 30720000
+
+        # BUG: Current code adds the SAME bytes to BOTH days.
+        # After fix: only ONE day should have the unattributed bytes.
+        # The spec says: preserve once as shared boundary evidence.
+        
+        # At least one day must have the unattributed bytes
+        total_unattr_w = (unattr_w_day1[0] if unattr_w_day1 else 0) +                          (unattr_w_day2[0] if unattr_w_day2 else 0)
+        total_unattr_r = (unattr_r_day1[0] if unattr_r_day1 else 0) +                          (unattr_r_day2[0] if unattr_r_day2 else 0)
+        
+        # The total unattributed bytes across both days must equal
+        # the actual delta (not double)
+        assert total_unattr_w == expected_bw, (
+            f"Unattributed writes across both days should be {expected_bw}, "
+            f"got {total_unattr_w} (duplication detected)"
+        )
+        assert total_unattr_r == expected_br, (
+            f"Unattributed reads across both days should be {expected_br}, "
+            f"got {total_unattr_r} (duplication detected)"
+        )
+        
+        # Neither day should have MORE than the actual delta
+        for day_label, uw, ur in [
+            ("day1", unattr_w_day1, unattr_r_day1),
+            ("day2", unattr_w_day2, unattr_r_day2),
+        ]:
+            if uw is not None:
+                assert uw[0] <= expected_bw, (
+                    f"{day_label} unattributed writes {uw[0]} exceeds delta {expected_bw}"
+                )
+            if ur is not None:
+                assert ur[0] <= expected_br, (
+                    f"{day_label} unattributed reads {ur[0]} exceeds delta {expected_br}"
+                )
+
+        conn.close()

tests/test_dashboard_design.py

@@ -0,0 +1,176 @@
+"""User-facing navigation, zoom, and plotted volume in the redesigned dashboard."""
+from datetime import datetime, timedelta, timezone
+from xml.etree import ElementTree
+
+import pytest
+from test_tui import (
+    _insert_baseline,
+    _insert_day,
+    _insert_local_day,
+    _insert_segment,
+    _open_period,
+)
+
+from fenris.store import init_store
+from fenris.tui import FenrisTuiApp
+
+NOW = datetime(2026, 9, 19, 12, tzinfo=timezone.utc)
+
+
+@pytest.fixture
+def dashboard(tmp_path, monkeypatch):
+    monkeypatch.setenv("XDG_CONFIG_HOME", str(tmp_path / "prefs"))
+
+    class Clock(datetime):
+        @classmethod
+        def now(cls, tz=None):
+            return NOW
+
+    monkeypatch.setattr("fenris.tui.datetime", Clock)
+    monkeypatch.setattr("fenris.status.query_service_state", lambda: {
+        "boot_enabled": True, "timer_active": True, "last_collect_ok": True,
+        "last_collect_age_s": 0, "last_collect_reason": None,
+    })
+    conn = init_store(tmp_path / "test.db")
+    _insert_segment(conn)
+    _insert_baseline(conn)
+    _open_period(conn)
+    for offset in range(18):
+        date = (NOW - timedelta(days=offset)).date().isoformat()
+        _insert_day(conn, date, bw=(offset + 1) * 1_000_000_000)
+        _insert_local_day(conn, date, bw=(offset + 1) * 1_000_000_000, br=2_000_000_000)
+    for index in range(61):
+        conn.execute(
+            "INSERT INTO samples (ts, device, bytes_written, bytes_read, segment_id) VALUES (?, ?, ?, ?, ?)",
+            ((NOW - timedelta(minutes=(60 - index) * 3)).isoformat(),
+             "/dev/test", index * 1_000_000, index * 2_000_000, 1),
+        )
+    conn.execute(
+        "INSERT INTO hour_observations (hour, bytes_written_delta, bytes_read_delta, coverage, sample_count) "
+        "VALUES (?, ?, ?, ?, ?)", ("2026-09-18T12:00:00+00:00", 4_000_000, 8_000_000, 1, 20),
+    )
+    conn.commit()
+    conn.close()
+    return FenrisTuiApp(store_path=tmp_path / "test.db", refresh_interval_s=999)
+
+
+def visible(app):
+    return " ".join("".join(ElementTree.fromstring(app.export_screenshot()).itertext()).split())
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize("size", [(140, 44), (80, 24)])
+async def test_live_plot_inspection_zoom_refresh_and_resize(dashboard, size):
+    app = dashboard
+    async with app.run_test(size=size) as pilot:
+        app.on_refresh_tick()
+        await pilot.pause()
+        assert app.theme == "fenris-chalktone"
+        graph = app.query_one("#live-activity")
+        assert app.focused is graph
+        await pilot.press("left", "w")
+        selected = str(app.query_one("#live-readout").render())
+        assert "11:54" in selected and "W 0.001 GB" in selected and "R 0.002 GB" in selected
+        assert "Reads" in str(app.query_one("#live-legend").render())
+        await pilot.press("z")
+        app.on_refresh_tick()
+        await pilot.pause()
+        assert str(app.query_one("#live-readout").render()) == selected
+        assert app.query_one("#activity-panel").region.width == size[0]
+        for fact in ("Freshness:", "Last collect:", "Boot:", "Timer:", "q Quit TUI"):
+            assert fact in visible(app)
+        await pilot.resize_terminal(100, 30)
+        await pilot.press("escape")
+        assert str(app.query_one("#live-readout").render()) == selected
+        assert app._zoomed_panel is None
+        assert app.query_one("#action-rail").region.bottom <= 30
+
+
+@pytest.mark.asyncio
+async def test_tabs_date_entry_and_hourly_inspection_keep_context(dashboard):
+    app = dashboard
+    async with app.run_test(size=(100, 36)) as pilot:
+        await pilot.click("#view-history")
+        await pilot.press("left", "enter")
+        assert app.query_one("#activity-tabs").active == "view-day"
+        assert "2026-09-18" in str(app.query_one("#local-day").render())
+        # Hour 23 is selected initially; move to the known hour 12.
+        await pilot.press(*(["left"] * 11))
+        readout = str(app.query_one("#bar-readout").render())
+        assert "12:00 UTC" in readout and "W 0.004 GB" in readout
+        await pilot.press("z", "w")
+        app.on_refresh_tick()
+        await pilot.pause()
+        assert str(app.query_one("#bar-readout").render()) == readout
+        await pilot.press("g")
+        await pilot.press(*list("2026-09-17"))
+        await pilot.press("escape")
+        assert str(app.query_one("#bar-readout").render()) == readout
+        assert app._zoomed_panel == "activity-panel"
+        await pilot.press("escape", "t")
+        assert app.query_one("#activity-tabs").active == "view-live"
+
+
+@pytest.mark.asyncio
+async def test_mouse_inspection_matches_time_axis(dashboard):
+    app = dashboard
+    async with app.run_test(size=(100, 36)) as pilot:
+        await pilot.pause()
+        graph = app.query_one("#live-activity")
+        x = graph._point_columns[0]
+        await pilot.click("#live-render", offset=(x, 1))
+        text = str(app.query_one("#live-readout").render())
+        assert "09:00 → 09:03 UTC" in text
+
+
+@pytest.mark.asyncio
+async def test_theme_control_persists_choice_and_quit_never_pauses(dashboard, monkeypatch):
+    calls = []
+    monkeypatch.setattr(dashboard, "_run_helper", lambda *args: calls.append(args))
+    async with dashboard.run_test(size=(80, 24)) as pilot:
+        await pilot.press("s")
+        assert dashboard.theme == "fenris-amber"
+        await pilot.press("q")
+    assert calls == []
+    from fenris.preferences import load_preferences
+    assert load_preferences()["theme"] == "amber"
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize("size", [(100, 36), (70, 20)])
+async def test_unallocated_volume_survives_day_with_missing_coverage(dashboard, size):
+    async with dashboard.run_test(size=size) as pilot:
+        await pilot.click("#view-history")
+        graph = dashboard.query_one("#usage-history")
+        graph.set_data([{
+            "day": "2026-09-18", "total_bytes": 2_000_000_000,
+            "unallocated_bytes": 2_000_000_000, "is_gap": True,
+            "is_partial": True,
+        }])
+        readout = str(dashboard.query_one("#bar-readout").render())
+        assert "W 2.000 GB unallocated" in readout
+        assert "R unavailable" in readout and "gap" in readout
+        if size[0] >= 80:
+            plot = str(dashboard.query_one("#bar-render").render())
+            assert any(0x2801 <= ord(c) <= 0x28ff for c in plot)
+            graph.measure = "read"
+            graph._refresh()
+            plot = str(dashboard.query_one("#bar-render").render())
+            assert not any(0x2801 <= ord(c) <= 0x28ff for c in plot)
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize("state", ["gap", "future"])
+async def test_small_terminal_hour_readout_does_not_invent_zero(dashboard, state):
+    async with dashboard.run_test(size=(70, 20)) as pilot:
+        await pilot.click("#view-day")
+        graph = dashboard.query_one("#usage-history")
+        graph.set_hour_data([{
+            "hour": "2026-09-18T12:00:00+00:00", "local_label": "12",
+            "is_gap": state == "gap", "is_future": state == "future",
+        }])
+        graph._hourly_selected = 0
+        graph._refresh_hourly()
+        readout = str(dashboard.query_one("#bar-readout").render())
+        assert "W unavailable · R unavailable" in readout
+        assert state in readout and "12:00 UTC" in readout

tests/test_init_system.py

@@ -634,6 +634,14 @@ class TestMonitorIntegration:
             cmd_enable(args)
             mock_enable.assert_called_once_with(True)
 
+        conn = sqlite3.connect(store_path)
+        try:
+            assert conn.execute(
+                "SELECT COUNT(*) FROM monitoring_periods WHERE ended_at IS NULL"
+            ).fetchone()[0] == 1
+        finally:
+            conn.close()
+
     def test_cmd_disable_uses_init_system(self, tmp_path):
         """cmd_disable uses init_system.disable_timer."""
         from fenris.monitor import cmd_disable

tests/test_issue_100.py

@@ -0,0 +1,341 @@
+"""Normal-collection retention acceptance tests for issue #100."""
+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.collector import run_collection
+from fenris.local_day import query_local_day_summary
+from fenris.pruning import prune_old_samples
+from fenris.status import read_status
+from fenris.store import init_store
+
+
+@pytest.fixture
+def sysfs_controller(tmp_path):
+    controller = tmp_path / "sys" / "class" / "nvme" / "nvme0"
+    controller.mkdir(parents=True)
+    (controller / "subsysnqn").write_text("nqn.example:drive-1\n")
+    (controller / "model").write_text("Fenris Test Drive\n")
+    (controller / "serial").write_text("drive-1\n")
+    (controller / "firmware_rev").write_text("1.0\n")
+    transport = controller / "transport"
+    transport.mkdir()
+    (transport / "address").write_text("0000:00:01.0\n")
+    (transport / "trstring").write_text("pcie\n")
+    return controller
+
+
+class FakeClock:
+    def __init__(self, now):
+        self.now = now
+
+    def utcnow(self):
+        return self.now
+
+
+def _smartctl(written, read):
+    return {
+        "nvme_smart_health_information_log": {
+            "critical_warning": 0,
+            "temperature": 35,
+            "available_spare": 100,
+            "percentage_used": 1,
+            "data_units_written": written,
+            "data_units_read": read,
+            "power_on_hours": 100,
+            "power_cycles": 1,
+            "unsafe_shutdowns": 0,
+            "media_errors": 0,
+        },
+        "user_capacity": {"bytes": 1_000_000_000_000},
+        "model_name": "Fenris Test Drive",
+        "serial_number": "drive-1",
+        "firmware_version": "1.0",
+    }
+
+
+def _collect(config, controller, now, written, read):
+    return run_collection(
+        smartctl_data=_smartctl(written, read),
+        sysfs_path=controller,
+        config=config,
+        clock=FakeClock(now),
+    )
+
+
+def test_normal_collection_expires_detail_and_keeps_local_day_evidence(
+    tmp_path, sysfs_controller, monkeypatch,
+):
+    monkeypatch.setenv("TZ", "UTC")
+    store_path = tmp_path / "observations.db"
+    config = {"device": "/dev/nvme0", "store_path": str(store_path)}
+    first_time = datetime(2026, 9, 1, 0, 0, tzinfo=timezone.utc)
+    second_time = first_time + timedelta(days=15)
+
+    first = _collect(config, sysfs_controller, first_time, 1000, 2000)
+    assert first["ok"] is True, first
+    second = _collect(config, sysfs_controller, second_time, 1001, 2003)
+    assert second["ok"] is True, second
+
+    with sqlite3.connect(store_path) as conn:
+        assert conn.execute("SELECT ts FROM samples ORDER BY id").fetchall() == [
+            (second_time.isoformat(),)
+        ]
+        assert conn.execute(
+            "SELECT bytes_written, bytes_read, reason "
+            "FROM local_day_unallocated_evidence"
+        ).fetchall() == [(512_000, 1_536_000, "local_midnight")]
+        assert conn.execute("SELECT COUNT(*) FROM pending_publications").fetchone()[0] == 0
+        assert conn.execute("SELECT COUNT(*) FROM controller_segments").fetchone()[0] == 1
+        assert conn.execute("SELECT COUNT(*) FROM day_aggregates").fetchone()[0] == 15
+
+    monkeypatch.setenv("TZ", "Asia/Kolkata")
+    with read_status(store_path, second_time, query_services=False) as (reader, state):
+        assert reader is not None
+        assert state.store_fault is None
+        old_day = query_local_day_summary(
+            reader, "2026-09-01", "UTC", second_time,
+        )
+        assert old_day["utc_start"] == "2026-09-01T00:00:00+00:00"
+        assert old_day["utc_end"] == "2026-09-02T00:00:00+00:00"
+        assert old_day["bytes_written"] is None
+        assert old_day["shared_bytes_written"] == 512_000
+        assert old_day["shared_bytes_read"] == 1_536_000
+        assert old_day["shared_evidence_count"] == 1
+
+
+def test_pruning_keeps_samples_when_replacement_evidence_is_missing(tmp_path):
+    store_path = tmp_path / "incomplete.db"
+    conn = init_store(store_path)
+    now = datetime(2026, 9, 30, tzinfo=timezone.utc)
+    old_time = now - timedelta(days=20)
+    next_time = now - timedelta(days=1)
+    conn.execute(
+        "INSERT INTO controller_segments (id, opened_at, identity_key) "
+        "VALUES (1, ?, 'test')",
+        (old_time.isoformat(),),
+    )
+    conn.execute(
+        "INSERT INTO samples (ts, device, bytes_written, bytes_read, segment_id, local_tz) "
+        "VALUES (?, '/dev/nvme0', 100, 100, 1, 'UTC')",
+        (old_time.isoformat(),),
+    )
+    conn.execute(
+        "INSERT INTO samples (ts, device, bytes_written, bytes_read, segment_id, local_tz) "
+        "VALUES (?, '/dev/nvme0', 200, 200, 1, 'UTC')",
+        (next_time.isoformat(),),
+    )
+    conn.commit()
+
+    assert prune_old_samples(conn, now) == 0
+    assert conn.execute("SELECT COUNT(*) FROM samples").fetchone()[0] == 2
+    conn.close()
+
+
+def test_later_same_day_activity_does_not_replace_gap_interval(tmp_path):
+    store_path = tmp_path / "unrelated-local-activity.db"
+    conn = init_store(store_path)
+    gap_start = datetime(2026, 9, 1, 0, 0, tzinfo=timezone.utc)
+    gap_end = gap_start + timedelta(minutes=10)
+    later_end = gap_start + timedelta(minutes=20)
+    now = datetime(2026, 9, 30, tzinfo=timezone.utc)
+    conn.execute(
+        "INSERT INTO controller_segments (id, opened_at, identity_key) "
+        "VALUES (1, ?, 'test')",
+        (gap_start.isoformat(),),
+    )
+    for sample_time, written, read in (
+        (gap_start, 1000, 100),
+        (gap_end, 2000, 200),
+        (later_end, 2100, 210),
+    ):
+        conn.execute(
+            "INSERT INTO samples (ts, device, bytes_written, bytes_read, segment_id, local_tz) "
+            "VALUES (?, '/dev/nvme0', ?, ?, 1, 'UTC')",
+            (sample_time.isoformat(), written, read),
+        )
+
+    # UTC aggregates can replace the old counter pair, but the local-day
+    # summary contains only the later B->C interval, after monitoring resumed.
+    conn.execute(
+        "INSERT INTO hour_observations (hour, bytes_written_delta, bytes_read_delta) "
+        "VALUES ('2026-09-01T00:00:00+00:00', 1000, 100)"
+    )
+    conn.execute(
+        "INSERT INTO day_aggregates (day) VALUES ('2026-09-01')"
+    )
+    conn.execute(
+        "INSERT INTO monitoring_periods (started_at, ended_at) VALUES (?, ?)",
+        (gap_end.isoformat(), later_end.isoformat()),
+    )
+    last_sample_id = conn.execute("SELECT MAX(id) FROM samples").fetchone()[0]
+    conn.execute(
+        "INSERT INTO local_days "
+        "(local_date, tz_name, tz_offset, utc_start, utc_end, bytes_written, "
+        " bytes_read, activity_intervals, activity_precision, last_sample_id) "
+        "VALUES ('2026-09-01', 'UTC', '+00:00', ?, ?, 100, 10, 1, 'measured', ?)",
+        (
+            gap_start.isoformat(),
+            (gap_start + timedelta(days=1)).isoformat(),
+            last_sample_id,
+        ),
+    )
+    local_day_id = conn.execute("SELECT MAX(id) FROM local_days").fetchone()[0]
+    conn.execute(
+        "INSERT INTO local_day_segment_totals "
+        "(local_day_id, segment_id, bytes_written, bytes_read, activity_intervals) "
+        "VALUES (?, 1, 100, 10, 1)",
+        (local_day_id,),
+    )
+    conn.commit()
+
+    assert prune_old_samples(conn, now) == 0
+    assert conn.execute("SELECT COUNT(*) FROM samples").fetchone()[0] == 3
+    conn.close()
+
+
+def test_pruning_keeps_oldest_unpaired_sample_as_successor_anchor(tmp_path):
+    store_path = tmp_path / "anchor.db"
+    conn = init_store(store_path)
+    now = datetime(2026, 9, 30, tzinfo=timezone.utc)
+    old_time = now - timedelta(days=20)
+    conn.execute(
+        "INSERT INTO controller_segments (id, opened_at, identity_key) "
+        "VALUES (1, ?, 'test')",
+        (old_time.isoformat(),),
+    )
+    conn.execute(
+        "INSERT INTO samples (ts, device, bytes_written, bytes_read, segment_id, local_tz) "
+        "VALUES (?, '/dev/nvme0', 100, 100, 1, 'UTC')",
+        (old_time.isoformat(),),
+    )
+    conn.commit()
+
+    assert prune_old_samples(conn, now) == 0
+    assert conn.execute("SELECT ts FROM samples").fetchone()[0] == old_time.isoformat()
+    conn.close()
+
+
+def test_pruning_never_expires_pending_publications(tmp_path):
+    store_path = tmp_path / "pending.db"
+    conn = init_store(store_path)
+    old_time = datetime(2026, 9, 1, tzinfo=timezone.utc)
+    conn.execute(
+        "INSERT INTO pending_publications (sample_ts, payload) VALUES (?, '{}')",
+        (old_time.isoformat(),),
+    )
+    conn.commit()
+
+    assert prune_old_samples(
+        conn, datetime(2026, 9, 30, tzinfo=timezone.utc),
+    ) == 0
+    assert conn.execute(
+        "SELECT sample_ts FROM pending_publications"
+    ).fetchone()[0] == old_time.isoformat()
+    conn.close()
+
+
+def test_pruning_preserves_unparseable_legacy_timestamp(tmp_path):
+    store_path = tmp_path / "legacy.db"
+    conn = init_store(store_path)
+    conn.execute(
+        "INSERT INTO samples (ts, device, bytes_written, bytes_read) "
+        "VALUES ('legacy timestamp', '/dev/nvme0', 100, 100)"
+    )
+    conn.commit()
+
+    assert prune_old_samples(conn, datetime(2026, 9, 30, tzinfo=timezone.utc)) == 0
+    assert conn.execute("SELECT ts FROM samples").fetchone()[0] == "legacy timestamp"
+    conn.close()
+
+
+def test_collection_defers_interrupted_pruning_and_retries_next_run(
+    tmp_path, sysfs_controller, monkeypatch,
+):
+    monkeypatch.setenv("TZ", "UTC")
+    store_path = tmp_path / "interrupted.db"
+    config = {"device": "/dev/nvme0", "store_path": str(store_path)}
+    first_time = datetime(2026, 9, 1, 0, 0, tzinfo=timezone.utc)
+    second_time = first_time + timedelta(days=15)
+    assert _collect(config, sysfs_controller, first_time, 1000, 2000)["ok"] is True
+
+    writer = sqlite3.connect(store_path)
+    writer.execute(
+        "CREATE TRIGGER stop_retention BEFORE DELETE ON samples "
+        "BEGIN SELECT RAISE(ABORT, 'simulated retention interruption'); END"
+    )
+    writer.commit()
+    writer.close()
+
+    second = _collect(config, sysfs_controller, second_time, 1001, 2001)
+    assert second["ok"] is True, second
+    assert "simulated retention interruption" in second["retention_error"]
+    with sqlite3.connect(store_path) as conn:
+        assert conn.execute("SELECT COUNT(*) FROM samples").fetchone()[0] == 2
+        assert conn.execute("SELECT COUNT(*) FROM pending_publications").fetchone()[0] == 0
+        assert conn.execute("SELECT COUNT(*) FROM local_day_unallocated_evidence").fetchone()[0] == 1
+
+    writer = sqlite3.connect(store_path)
+    writer.execute("DROP TRIGGER stop_retention")
+    writer.commit()
+    writer.close()
+
+    third_time = second_time + timedelta(days=15)
+    third = _collect(config, sysfs_controller, third_time, 1002, 2002)
+    assert third["ok"] is True, third
+    assert third["retention_error"] is None
+    with sqlite3.connect(store_path) as conn:
+        assert conn.execute("SELECT ts FROM samples ORDER BY id").fetchall() == [
+            (third_time.isoformat(),)
+        ]
+
+
+def test_collection_recovers_old_pending_work_before_pruning(
+    tmp_path, sysfs_controller, monkeypatch,
+):
+    monkeypatch.setenv("TZ", "UTC")
+    store_path = tmp_path / "pending-recovery.db"
+    config = {"device": "/dev/nvme0", "store_path": str(store_path)}
+    first_time = datetime(2026, 9, 1, 0, 0, tzinfo=timezone.utc)
+    second_time = first_time + timedelta(days=15)
+    assert _collect(config, sysfs_controller, first_time, 1000, 2000)["ok"] is True
+
+    writer = sqlite3.connect(store_path)
+    writer.execute(
+        "CREATE TRIGGER interrupt_publication "
+        "BEFORE INSERT ON local_day_unallocated_evidence "
+        "BEGIN SELECT RAISE(ABORT, 'simulated publication interruption'); END"
+    )
+    writer.commit()
+    writer.close()
+
+    failed = _collect(config, sysfs_controller, second_time, 1001, 2001)
+    assert failed["ok"] is False
+    assert "simulated publication interruption" in failed["error"]
+    with sqlite3.connect(store_path) as conn:
+        assert conn.execute("SELECT COUNT(*) FROM samples").fetchone()[0] == 1
+        assert conn.execute("SELECT COUNT(*) FROM pending_publications").fetchone()[0] == 1
+
+    writer = sqlite3.connect(store_path)
+    writer.execute("DROP TRIGGER interrupt_publication")
+    writer.commit()
+    writer.close()
+
+    third_time = second_time + timedelta(minutes=5)
+    recovered = _collect(config, sysfs_controller, third_time, 1002, 2002)
+    assert recovered["ok"] is True, recovered
+    assert recovered["retention_error"] is None
+    with sqlite3.connect(store_path) as conn:
+        assert conn.execute("SELECT COUNT(*) FROM pending_publications").fetchone()[0] == 0
+        assert conn.execute("SELECT ts FROM samples ORDER BY id").fetchall() == [
+            (second_time.isoformat(),),
+            (third_time.isoformat(),),
+        ]
+        assert conn.execute(
+            "SELECT COUNT(*) FROM local_day_unallocated_evidence"
+        ).fetchone()[0] == 1

tests/test_issue_101.py

@@ -0,0 +1,257 @@
+"""Bound pending-publication admission before device acquisition."""
+import json
+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 import collector
+
+
+class FakeClock:
+    def __init__(self, now):
+        self.now = now
+
+    def utcnow(self):
+        return self.now
+
+
+@pytest.fixture
+def sysfs_controller(tmp_path):
+    controller_path = tmp_path / "sys" / "class" / "nvme" / "nvme0"
+    controller_path.mkdir(parents=True)
+    (controller_path / "subsysnqn").write_text("nqn.test:drive\n")
+    (controller_path / "model").write_text("Test NVMe\n")
+    (controller_path / "serial").write_text("test-serial\n")
+    (controller_path / "firmware_rev").write_text("1.0\n")
+    transport = controller_path / "transport"
+    transport.mkdir()
+    (transport / "trstring").write_text("pcie\n")
+    return controller_path
+
+
+def _smartctl(units_written):
+    return {
+        "nvme_smart_health_information_log": {
+            "critical_warning": 0,
+            "temperature": 35,
+            "available_spare": 100,
+            "percentage_used": 5,
+            "data_units_written": units_written,
+            "data_units_read": 500,
+            "power_on_hours": 100,
+        },
+        "user_capacity": {"bytes": 1_024_000_000_000},
+        "model_name": "Test NVMe",
+        "serial_number": "test-serial",
+        "firmware_version": "1.0",
+    }
+
+
+def _collect(config, controller, now, units_written):
+    return collector.run_collection(
+        config=config,
+        clock=FakeClock(now),
+        acquire=lambda: (_smartctl(units_written), controller),
+    )
+
+
+def test_partial_recovery_frees_admission_and_keeps_pending_order(
+    tmp_path, sysfs_controller, monkeypatch,
+):
+    """A freed slot admits one observation behind older pending evidence."""
+    assert collector.PENDING_PUBLICATION_LIMIT == 6_720
+    monkeypatch.setenv("TZ", "UTC")
+    monkeypatch.setattr(collector, "PENDING_PUBLICATION_LIMIT", 2)
+
+    store_path = tmp_path / "observations.db"
+    config = {"device": "/dev/nvme0", "store_path": str(store_path)}
+    old_time = datetime(2026, 8, 1, tzinfo=timezone.utc)
+    controller = sysfs_controller
+
+    assert _collect(config, controller, old_time, 1000)["ok"] is True
+
+    original_derive = collector.derive_hours_from_interval
+
+    def unavailable_derivation(*_args):
+        raise RuntimeError("derivation unavailable")
+
+    monkeypatch.setattr(collector, "derive_hours_from_interval", unavailable_derivation)
+    first_pending = _collect(
+        config, controller, old_time + timedelta(minutes=5), 1010,
+    )
+    assert first_pending["ok"] is False
+
+    second_pending = _collect(
+        config, controller, old_time + timedelta(minutes=10), 1020,
+    )
+    assert second_pending["ok"] is False
+    with sqlite3.connect(store_path) as conn:
+        assert conn.execute(
+            "SELECT COUNT(*) FROM pending_publications"
+        ).fetchone()[0] == 2
+
+    called = False
+
+    def must_not_acquire():
+        nonlocal called
+        called = True
+        return _smartctl(1030), controller
+
+    full = collector.run_collection(
+        config=config,
+        clock=FakeClock(old_time + timedelta(days=40)),
+        acquire=must_not_acquire,
+    )
+    assert full["ok"] is False
+    assert "capacity full (2 observations)" in full["error"]
+    assert called is False
+    with sqlite3.connect(store_path) as conn:
+        assert conn.execute(
+            "SELECT COUNT(*), MIN(sample_ts) FROM pending_publications"
+        ).fetchone() == (
+            2,
+            (old_time + timedelta(minutes=5)).isoformat(),
+        )
+        assert conn.execute("SELECT COUNT(*) FROM samples").fetchone()[0] == 1
+
+    def fail_second_pending(conn, previous, current):
+        if current["data_units_written"] == 1020:
+            raise RuntimeError("second observation still blocked")
+        return original_derive(conn, previous, current)
+
+    monkeypatch.setattr(collector, "derive_hours_from_interval", fail_second_pending)
+    acquired = False
+
+    def acquire_after_partial_recovery():
+        nonlocal acquired
+        acquired = True
+        return _smartctl(1030), controller
+
+    partial = collector.run_collection(
+        config=config,
+        clock=FakeClock(old_time + timedelta(days=40, minutes=5)),
+        acquire=acquire_after_partial_recovery,
+    )
+    assert partial["ok"] is False
+    assert acquired is True, partial
+    assert "no new observation acquired" not in partial["error"]
+
+    with sqlite3.connect(store_path) as conn:
+        assert conn.execute(
+            "SELECT data_units_written FROM samples ORDER BY id"
+        ).fetchall() == [(1000,), (1010,)]
+        queued_units = [
+            json.loads(row[0])["sample"]["data_units_written"]
+            for row in conn.execute(
+                "SELECT payload FROM pending_publications ORDER BY id"
+            )
+        ]
+        assert queued_units == [1020, 1030]
+        assert conn.execute("SELECT COUNT(*) FROM monitoring_periods").fetchone()[0] == 1
+
+    recovered_in_order = []
+
+    def record_recovery_order(conn, previous, current):
+        recovered_in_order.append(current["data_units_written"])
+        return original_derive(conn, previous, current)
+
+    monkeypatch.setattr(collector, "derive_hours_from_interval", record_recovery_order)
+    recovered = collector.run_collection(
+        config=config,
+        clock=FakeClock(old_time + timedelta(days=40, minutes=10)),
+        acquire=lambda: (_smartctl(1040), controller),
+    )
+    assert recovered["ok"] is True, recovered
+    assert recovered_in_order == [1020, 1030, 1040]
+
+    with sqlite3.connect(store_path) as conn:
+        assert conn.execute(
+            "SELECT data_units_written FROM samples ORDER BY id DESC LIMIT 1"
+        ).fetchone() == (1040,)
+        assert conn.execute("SELECT COUNT(*) FROM pending_publications").fetchone()[0] == 0
+
+
+def test_actual_pending_limit_fails_before_acquisition_and_keeps_old_evidence(
+    tmp_path, sysfs_controller, monkeypatch,
+):
+    """The production limit retains every old row and refuses device acquisition."""
+    monkeypatch.setenv("TZ", "UTC")
+    store_path = tmp_path / "full-observations.db"
+    config = {"device": "/dev/nvme0", "store_path": str(store_path)}
+    controller = sysfs_controller
+    old_time = datetime(2026, 7, 1, tzinfo=timezone.utc)
+    assert _collect(config, controller, old_time, 1000)["ok"] is True
+
+    def unavailable_derivation(*_args):
+        raise RuntimeError("derivation unavailable")
+
+    monkeypatch.setattr(collector, "derive_hours_from_interval", unavailable_derivation)
+    failed = _collect(
+        config, controller, old_time + timedelta(minutes=5), 1010,
+    )
+    assert failed["ok"] is False
+
+    with sqlite3.connect(store_path) as conn:
+        payload_row = conn.execute(
+            "SELECT payload FROM pending_publications ORDER BY id LIMIT 1"
+        ).fetchone()
+        assert payload_row is not None
+        base = json.loads(payload_row[0])
+        base_observed_at = datetime.fromisoformat(base["sample"]["ts"])
+        base_units = base["sample"]["data_units_written"]
+        rows = []
+        for offset in range(1, collector.PENDING_PUBLICATION_LIMIT):
+            observation = json.loads(payload_row[0])
+            units_written = base_units + offset
+            observed_at = base_observed_at + timedelta(minutes=5 * offset)
+            observation["sample"]["ts"] = observed_at.isoformat()
+            observation["sample"]["data_units_written"] = units_written
+            observation["sample"]["bytes_written"] = units_written * 512_000
+            rows.append((observed_at.isoformat(), json.dumps(observation)))
+        conn.executemany(
+            "INSERT INTO pending_publications (sample_ts, payload) VALUES (?, ?)",
+            rows,
+        )
+        conn.commit()
+
+    called = False
+
+    def must_not_acquire():
+        nonlocal called
+        called = True
+        return _smartctl(9000), controller
+
+    result = collector.run_collection(
+        config=config,
+        clock=FakeClock(old_time + timedelta(days=40)),
+        acquire=must_not_acquire,
+    )
+    assert result["ok"] is False
+    assert f"capacity full ({collector.PENDING_PUBLICATION_LIMIT} observations)" in result[
+        "error"
+    ]
+    assert called is False
+
+    with sqlite3.connect(store_path) as conn:
+        pending_rows = conn.execute(
+            "SELECT sample_ts, payload FROM pending_publications ORDER BY id"
+        ).fetchall()
+        assert len(pending_rows) == collector.PENDING_PUBLICATION_LIMIT
+        assert (pending_rows[0][0], pending_rows[-1][0]) == (
+            (old_time + timedelta(minutes=5)).isoformat(),
+            (
+                old_time
+                + timedelta(minutes=5 * collector.PENDING_PUBLICATION_LIMIT)
+            ).isoformat(),
+        )
+        assert [
+            json.loads(payload)["sample"]["data_units_written"]
+            for _, payload in pending_rows
+        ] == list(range(1010, 1010 + collector.PENDING_PUBLICATION_LIMIT))
+        assert conn.execute("SELECT COUNT(*) FROM samples").fetchone()[0] == 1
+        assert conn.execute("SELECT COUNT(*) FROM monitoring_periods").fetchone()[0] == 1

tests/test_issue_72_edge_cases.py

@@ -0,0 +1,376 @@
+"""Edge-case tests for issue #72 remaining acceptance criteria.
+
+Covers:
+- TPH-#34-36: Pause-crossing intervals
+- TPH-#59: Staleness frozen estimate wording
+- TPH-#62: Zero-delta evidence in live graph
+- TPH-#63: Horizon anchoring at evidence endpoint
+- TPH-#64: Burst/habit checks with unknown daily shares
+"""
+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.derive import derive_hours_from_interval
+from fenris.day_aggregate import derive_day
+from fenris.projection import compute_projection, ConfidenceState, STALENESS_HOURS
+from fenris.tui import _query_live_graph_data, _query_daily_graph_data
+
+
+# ---------------------------------------------------------------------------
+# Fixtures
+# ---------------------------------------------------------------------------
+
+def _clock(year=2026, month=10, day=1, hour=12):
+    return datetime(year, month, day, hour, 0, 0, tzinfo=timezone.utc)
+
+
+def _insert_sample(conn, ts, bw=512000000000, br=256000000000, segment_id=1):
+    conn.execute(
+        "INSERT INTO samples (ts, device, data_units_written, data_units_read, "
+        "percentage_used, bytes_written, bytes_read, power_on_hours, segment_id) "
+        "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)",
+        (ts, "/dev/nvme0n1", 1000000, 500000, 5, bw, br, 8765, segment_id),
+    )
+    conn.commit()
+
+
+def _insert_segment(conn, opened_at="2026-09-01T00:00:00+00:00",
+                     identity_key="nqn.test", degraded=False):
+    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",
+         "Samsung SSD 970 EVO Plus 1TB", "FW1", "0x144d", "0x144d", "pcie"),
+    )
+    conn.commit()
+
+
+def _insert_baseline(conn, tbw_tb=1.0, verified=True):
+    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",
+         "Samsung SSD 970 EVO Plus 1TB", 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_day(conn, day, bw=10*1024*1024*1024, br=0, coverage=0.95, samples=24):
+    """Insert a day aggregate with ~10GB writes (realistic for projection)."""
+    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, br, samples, coverage),
+    )
+    conn.commit()
+
+
+def _insert_local_day(conn, local_date, tz_name="UTC", tz_offset="+00:00",
+                       utc_start=None, utc_end=None, bw=10*1024*1024*1024,
+                       br=0, coverage=0.95, samples=24, complete=True):
+    """Insert a local_days row for testing the observation day gate."""
+    if utc_start is None:
+        utc_start = local_date + "T00:00:00+00:00"
+    if utc_end is None:
+        dt = datetime.strptime(local_date, "%Y-%m-%d") + timedelta(days=1)
+        utc_end = dt.strftime("%Y-%m-%dT00:00:00+00:00")
+    conn.execute(
+        "INSERT INTO local_days "
+        "(local_date, tz_name, tz_offset, utc_start, utc_end, "
+        " bytes_written, bytes_read, coverage, sample_count, complete, activity_intervals) "
+        "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, 1)",
+        (local_date, tz_name, tz_offset, utc_start, utc_end,
+         bw, br, coverage, samples, complete),
+    )
+    conn.commit()
+
+
+def _insert_hour(conn, hour_iso, bw=0, br=0, sample_count=1,
+                 active=3600, idle=0, powered_off=0, unknown=0):
+    known = active + idle + powered_off
+    coverage = known / 3600.0
+    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, active, idle, powered_off, unknown, bw, br, sample_count, coverage),
+    )
+    conn.commit()
+
+
+# ---------------------------------------------------------------------------
+# TPH-#34-36: Pause-crossing intervals
+# ---------------------------------------------------------------------------
+
+class TestPauseCrossingIntervals:
+    """Intervals crossing a pause boundary preserve evidence correctly."""
+
+    def test_interval_crossing_pause_preserves_total(self, tmp_path):
+        """An interval that spans a pause boundary keeps the full delta
+        in hour observations; the monitoring-period exclusion happens at
+        the day-aggregate coverage level."""
+        conn = init_store(tmp_path / "test.db")
+        _insert_segment(conn)
+
+        t1 = datetime(2026, 10, 1, 10, 0, 0, tzinfo=timezone.utc)
+        t2 = datetime(2026, 10, 1, 11, 0, 0, tzinfo=timezone.utc)
+        t3 = datetime(2026, 10, 1, 12, 0, 0, tzinfo=timezone.utc)
+
+        ensure_period_open(conn, t1)
+        _insert_sample(conn, t1.isoformat(), bw=100000000000)
+        _insert_sample(conn, t2.isoformat(), bw=200000000000)
+
+        prev = {"id": 1, "ts": t1.isoformat(), "bytes_written": 100000000000,
+                "bytes_read": 0, "power_on_hours": 8765, "temperature_c": 35,
+                "data_units_written": 1000000, "data_units_read": 0}
+        curr = {"id": 2, "ts": t2.isoformat(), "bytes_written": 200000000000,
+                "bytes_read": 0, "power_on_hours": 8765, "temperature_c": 35,
+                "data_units_written": 2000000, "data_units_read": 0}
+        derive_hours_from_interval(conn, prev, curr)
+
+        close_period(conn, t2, "user_disabled")
+        ensure_period_open(conn, t3)
+        _insert_sample(conn, t3.isoformat(), bw=300000000000)
+
+        prev2 = {"id": 2, "ts": t2.isoformat(), "bytes_written": 200000000000,
+                 "bytes_read": 0, "power_on_hours": 8765, "temperature_c": 35,
+                 "data_units_written": 2000000, "data_units_read": 0}
+        curr2 = {"id": 3, "ts": t3.isoformat(), "bytes_written": 300000000000,
+                 "bytes_read": 0, "power_on_hours": 8765, "temperature_c": 35,
+                 "data_units_written": 3000000, "data_units_read": 0}
+        derive_hours_from_interval(conn, prev2, curr2)
+
+        hour11 = conn.execute(
+            "SELECT bytes_written_delta FROM hour_observations WHERE hour = ?",
+            ("2026-10-01T11:00:00+00:00",)
+        ).fetchone()
+        assert hour11 is not None
+        assert hour11[0] == 100000000000
+
+        agg = derive_day(conn, "2026-10-01")
+        assert agg is not None
+        assert agg.bytes_written_delta == 100000000000
+
+        conn.close()
+
+    def test_deliberate_pause_vs_raw_stop(self, tmp_path):
+        """Deliberate pause closes period with user_disabled;
+        raw service stop leaves period open (interrupted)."""
+        conn = init_store(tmp_path / "test.db")
+        _insert_segment(conn)
+
+        t1 = datetime(2026, 10, 1, 10, 0, 0, tzinfo=timezone.utc)
+        ensure_period_open(conn, t1)
+        _insert_sample(conn, t1.isoformat())
+
+        close_period(conn, t1 + timedelta(hours=1), "user_disabled")
+
+        period = conn.execute(
+            "SELECT ended_at, end_cause FROM monitoring_periods WHERE ended_at IS NOT NULL"
+        ).fetchone()
+        assert period is not None
+        assert period[1] == "user_disabled"
+
+        t2 = datetime(2026, 10, 1, 14, 0, 0, tzinfo=timezone.utc)
+        ensure_period_open(conn, t2)
+        _insert_sample(conn, t2.isoformat())
+
+        open_periods = conn.execute(
+            "SELECT COUNT(*) FROM monitoring_periods WHERE ended_at IS NULL"
+        ).fetchone()
+        assert open_periods[0] == 1
+
+        conn.close()
+
+
+# ---------------------------------------------------------------------------
+# TPH-#59: Staleness frozen estimate wording
+# ---------------------------------------------------------------------------
+
+class TestStalenessFact:
+    """Projection includes staleness fact when evidence is old."""
+
+    def test_staleness_fact_present_when_old(self, tmp_path):
+        """When newest data is ≥48h old, projection includes staleness fact."""
+        conn = init_store(tmp_path / "test.db")
+        _insert_segment(conn)
+        _insert_baseline(conn)
+
+        base = datetime(2026, 9, 15, 12, 0, 0, tzinfo=timezone.utc)
+        for i in range(14):
+            day = (base + timedelta(days=i)).strftime("%Y-%m-%d")
+            _insert_day(conn, day, bw=10*1024*1024*1024)
+            _insert_local_day(conn, day, complete=True)
+
+        clock = datetime(2026, 10, 2, 12, 0, 0, tzinfo=timezone.utc)
+        proj = compute_projection(conn, clock)
+
+        assert proj.staleness_fact is not None
+        assert "48" in proj.staleness_fact or "old" in proj.staleness_fact
+
+        staleness_in_facts = any("old" in f or "48" in f for f in proj.contributing_facts)
+        assert staleness_in_facts
+
+        conn.close()
+
+    def test_no_staleness_fact_when_fresh(self, tmp_path):
+        """When newest data is recent, no staleness fact."""
+        conn = init_store(tmp_path / "test.db")
+        _insert_segment(conn)
+        _insert_baseline(conn)
+
+        base = datetime(2026, 9, 18, 12, 0, 0, tzinfo=timezone.utc)
+        for i in range(14):
+            day = (base + timedelta(days=i)).strftime("%Y-%m-%d")
+            _insert_day(conn, day, bw=10*1024*1024*1024)
+            _insert_local_day(conn, day, complete=True)
+
+        clock = datetime(2026, 10, 2, 12, 0, 0, tzinfo=timezone.utc)
+        proj = compute_projection(conn, clock)
+
+        assert proj.staleness_fact is None
+
+        conn.close()
+
+
+# ---------------------------------------------------------------------------
+# TPH-#62: Zero-delta evidence in live graph
+# ---------------------------------------------------------------------------
+
+class TestZeroDeltaEvidence:
+    """Zero-delta intervals are distinguished from missing evidence."""
+
+    def test_zero_delta_shown_as_zero(self, tmp_path):
+        """Two identical readings produce a zero-delta interval."""
+        conn = init_store(tmp_path / "test.db")
+        now = _clock()
+
+        _insert_sample(conn, (now - timedelta(minutes=6)).isoformat(), bw=100000000000)
+        _insert_sample(conn, (now - timedelta(minutes=3)).isoformat(), bw=100000000000)
+
+        data = _query_live_graph_data(conn, now)
+        assert len(data) == 1
+        assert data[0]["bytes_written"] == 0
+        assert data[0]["is_zero"] is True
+        assert data[0]["is_gap"] is False
+
+        conn.close()
+
+    def test_gap_distinguished_from_zero(self, tmp_path):
+        """A gap (missed collection) with non-zero delta is distinct from measured zero."""
+        conn = init_store(tmp_path / "test.db")
+        now = _clock()
+
+        _insert_sample(conn, (now - timedelta(hours=2)).isoformat(), bw=100000000000)
+        _insert_sample(conn, (now - timedelta(minutes=3)).isoformat(), bw=200000000000)
+
+        data = _query_live_graph_data(conn, now)
+        assert len(data) == 1
+        assert data[0]["is_gap"] is True
+        assert data[0]["is_zero"] is False
+        assert data[0]["bytes_written"] == 100000000000
+
+
+# ---------------------------------------------------------------------------
+# TPH-#63: Horizon anchoring at evidence endpoint
+# ---------------------------------------------------------------------------
+
+class TestHorizonAnchoring:
+    """Scenario windows end at the latest evidence endpoint T."""
+
+    def test_horizon_rate_uses_evidence_endpoint(self, tmp_path):
+        """Horizon rates are computed from the latest evidence endpoint,
+        not from clock_now."""
+        conn = init_store(tmp_path / "test.db")
+        _insert_segment(conn)
+        _insert_baseline(conn)
+        ensure_period_open(conn, datetime(2026, 9, 10, 0, 0, 0, tzinfo=timezone.utc))
+
+        # Insert 28 days of data ending 5 days ago with realistic writes
+        base = datetime(2026, 9, 10, 12, 0, 0, tzinfo=timezone.utc)
+        for i in range(28):
+            day = (base + timedelta(days=i)).strftime("%Y-%m-%d")
+            _insert_day(conn, day, bw=10*1024*1024*1024)  # ~10GB/day
+            _insert_local_day(conn, day, complete=True)
+
+        clock = datetime(2026, 10, 13, 12, 0, 0, tzinfo=timezone.utc)
+        proj = compute_projection(conn, clock)
+
+        # Scenario range should exist with rates
+        assert proj.scenario_range is not None
+        assert len(proj.scenario_range.rates) > 0
+
+        for horizon in [7, 28]:
+            if horizon in proj.scenario_range.rates:
+                rate = proj.scenario_range.rates[horizon]
+                assert rate > 0, f"Horizon {horizon} should have positive rate"
+
+        conn.close()
+
+
+# ---------------------------------------------------------------------------
+# TPH-#64: Burst/habit checks with unknown daily shares
+# ---------------------------------------------------------------------------
+
+class TestBurstChecks:
+    """Burst and habit checks handle unknown daily shares correctly."""
+
+    def test_habit_change_detected(self, tmp_path):
+        """Habit change detection works with clear write rate change."""
+        conn = init_store(tmp_path / "test.db")
+        _insert_segment(conn, opened_at="2026-08-01T00:00:00+00:00")
+        _insert_baseline(conn, tbw_tb=10.0)
+        ensure_period_open(conn, datetime(2026, 8, 1, 0, 0, 0, tzinfo=timezone.utc))
+
+        # 28 days of normal usage (100 MiB/day)
+        bw_normal = 100 * 1024 * 1024
+        for i in range(28):
+            day = (datetime(2026, 8, 1) + timedelta(days=i)).strftime("%Y-%m-%d")
+            _insert_day(conn, day, bw=bw_normal)
+            _insert_local_day(conn, day, complete=True, bw=bw_normal)
+
+        # 10 days of high usage (300 MiB/day = 3x, triggers habit change)
+        bw_high = 300 * 1024 * 1024
+        for i in range(10):
+            day = (datetime(2026, 8, 29) + timedelta(days=i)).strftime("%Y-%m-%d")
+            _insert_day(conn, day, bw=bw_high)
+            _insert_local_day(conn, day, complete=True, bw=bw_high)
+
+        clock = datetime(2026, 9, 8, 12, 0, 0, tzinfo=timezone.utc)
+        proj = compute_projection(conn, clock)
+
+        # Should have a habit change fact (3× increase for 10 days)
+        assert proj.habit_change_fact is not None
+        assert "usage habit changed" in proj.habit_change_fact
+
+        conn.close()
+
+    def test_zero_delta_not_treated_as_unknown(self, tmp_path):
+        """A measured zero-delta interval is not treated as missing evidence."""
+        conn = init_store(tmp_path / "test.db")
+        now = _clock()
+
+        _insert_sample(conn, (now - timedelta(minutes=6)).isoformat(), bw=100000000000)
+        _insert_sample(conn, (now - timedelta(minutes=3)).isoformat(), bw=100000000000)
+
+        data = _query_live_graph_data(conn, now)
+        assert len(data) == 1
+        assert data[0]["is_zero"] is True
+        assert data[0]["is_gap"] is False
+        assert data[0]["bytes_written"] == 0
+
+        conn.close()

tests/test_issue_77.py

@@ -86,6 +86,33 @@ def _open_period(conn, start="2026-09-01T00:00:00+00:00"):
     conn.commit()
 
 
+def _insert_local_day(conn, local_date, tz_name="UTC", tz_offset="+00:00",
+                       utc_start=None, utc_end=None, bw=1024*1024*100,
+                       br=0, coverage=0.95, samples=24, complete=True):
+    """Insert a local_days row (issue #94 gate prerequisite)."""
+    if utc_start is None:
+        utc_start = local_date + "T00:00:00+00:00"
+    if utc_end is None:
+        dt = datetime.strptime(local_date, "%Y-%m-%d") + timedelta(days=1)
+        utc_end = dt.strftime("%Y-%m-%dT00:00:00+00:00")
+    conn.execute(
+        "INSERT INTO local_days "
+        "(local_date, tz_name, tz_offset, utc_start, utc_end, "
+        " bytes_written, bytes_read, coverage, sample_count, complete, activity_intervals) "
+        "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, 1)",
+        (local_date, tz_name, tz_offset, utc_start, utc_end,
+         bw, br, coverage, samples, complete),
+    )
+    conn.commit()
+
+
+def _insert_complete_local_days(conn, start_date, count, bw=1024*1024*100):
+    """Insert multiple complete local days to satisfy the issue #94 gate."""
+    for i in range(count):
+        d = (datetime.strptime(start_date, "%Y-%m-%d") + timedelta(days=i)).strftime("%Y-%m-%d")
+        _insert_local_day(conn, d, bw=bw)
+
+
 class TestHonestQualifyingProgress:
     """Issue #77: Show honest qualifying-day progress and confidence."""
 
@@ -103,6 +130,7 @@ class TestHonestQualifyingProgress:
             _insert_day(store, d, bw=bw, coverage=cov)
         
         _insert_sample(store, "2026-09-30T10:00:00+00:00", pu=5)
+        _insert_complete_local_days(store, "2026-09-29", 1)
         result = compute_projection(store, _clock())
         
         # After warming, qualifying_days_progress shows honest count
@@ -125,6 +153,7 @@ class TestHonestQualifyingProgress:
             _insert_day(store, d, bw=bw, samples=samples)
         
         _insert_sample(store, "2026-09-30T10:00:00+00:00", pu=5)
+        _insert_complete_local_days(store, "2026-09-29", 1)
         result = compute_projection(store, _clock())
         
         # After warming, qualifying_days_progress shows honest count
@@ -146,6 +175,7 @@ class TestHonestQualifyingProgress:
             _insert_day(store, d, bw=bw, coverage=0.95)
         
         _insert_sample(store, "2026-09-30T10:00:00+00:00", pu=5)
+        _insert_complete_local_days(store, "2026-09-29", 1)
         result = compute_projection(store, _clock())
         
         # Should be warming
@@ -164,6 +194,7 @@ class TestHonestQualifyingProgress:
             _insert_day(store, d, bw=0, coverage=0.95)
         
         _insert_sample(store, "2026-09-30T10:00:00+00:00", pu=5)
+        _insert_complete_local_days(store, "2026-09-29", 1)
         result = compute_projection(store, _clock())
         
         # Zero rate should be UNSUPPORTED
@@ -185,6 +216,7 @@ class TestHonestQualifyingProgress:
             _insert_day(store, d, bw=bw, coverage=cov)
         
         _insert_sample(store, "2026-09-30T10:00:00+00:00", pu=5)
+        _insert_complete_local_days(store, "2026-09-29", 1)
         result = compute_projection(store, _clock())
         
         # Should still be warming (3 days below coverage > WARMING_MAX_LOW_COVERAGE=2)
@@ -205,6 +237,7 @@ class TestHonestQualifyingProgress:
             _insert_day(store, d, bw=bw, samples=samples)
         
         _insert_sample(store, "2026-09-30T10:00:00+00:00", pu=5)
+        _insert_complete_local_days(store, "2026-09-29", 1)
         result = compute_projection(store, _clock())
         
         # Should still be warming
@@ -225,6 +258,7 @@ class TestHonestQualifyingProgress:
             _insert_day(store, d, bw=bw, coverage=cov)
         
         _insert_sample(store, "2026-09-30T10:00:00+00:00", pu=5)
+        _insert_complete_local_days(store, "2026-09-29", 1)
         result = compute_projection(store, _clock())
         
         # Should not be warming (14 total, 2 below coverage <= WARMING_MAX_LOW_COVERAGE)
@@ -247,6 +281,7 @@ class TestHonestQualifyingProgress:
             _insert_day(store, d, bw=bw, coverage=0.95)
         
         _insert_sample(store, "2026-09-30T10:00:00+00:00", pu=5)
+        _insert_complete_local_days(store, "2026-09-29", 1)
         result = compute_projection(store, _clock())
         
         # Should not be warming

tests/test_issue_79.py

@@ -95,7 +95,7 @@ class TestFenrisIdentity:
         )
         async with app.run_test(size=(120, 24)) as pilot:
             headline = str(app.query_one("#headline-band").render())
-            assert "🐺 Fenris by Bongbetic" in headline
+            assert "🐺 Fenris by Bongbetic" in str(app.query_one("#identity").render())
 
     @pytest.mark.asyncio
     async def test_titlebox_fallback_without_wolf(self, tmp_path):
@@ -108,7 +108,7 @@ class TestFenrisIdentity:
         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
+            assert "Fenris by Bongbetic" in str(app.query_one("#identity").render())
 
     @pytest.mark.asyncio
     async def test_wolf_never_shows_tofu(self, tmp_path):
@@ -140,7 +140,7 @@ class TestFenrisIdentity:
         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 "🐺 Fenris by Bongbetic" in str(app.query_one("#identity").render())
             assert "remaining" in headline.lower() or "projection" in headline.lower()
 
 
@@ -174,7 +174,7 @@ class TestSingleMakerCredit:
         )
         async with app.run_test(size=(120, 24)) as pilot:
             headline = str(app.query_one("#headline-band").render())
-            assert "Fenris by Bongbetic" in headline
+            assert "Fenris by Bongbetic" in str(app.query_one("#identity").render())
 
     @pytest.mark.asyncio
     async def test_empty_store_no_maker_credit_in_strip(self, tmp_path):
@@ -275,7 +275,7 @@ class TestPreservedBehavior:
         """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())
+            rail = str(app.query_one("#action-rail").render())
             assert "q Quit TUI" in rail
 
     @pytest.mark.asyncio
@@ -287,11 +287,11 @@ class TestPreservedBehavior:
         )
         async with app.run_test(size=(120, 24)) as pilot:
             headline = str(app.query_one("#headline-band").render())
-            assert "polkit" in headline.lower()
+            assert "polkit" in str(app.query_one("#auth-notice").render()).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()
+            assert not app.query_one("#auth-notice").display
 
     @pytest.mark.asyncio
     async def test_deliberate_pause_block_preserved(self, tmp_path):

tests/test_issue_80.py

@@ -93,7 +93,7 @@ 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):
+    async def test_tui_applies_chalktone_theme_by_default(self, tmp_path):
         """TUI starts with the Amber theme when no preferences exist."""
         from fenris.tui import FenrisTuiApp
 
@@ -102,7 +102,7 @@ class TestPresetLoading:
             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"
+                assert app.theme == "fenris-chalktone"
 
     @pytest.mark.asyncio
     async def test_tui_applies_nord_theme_from_prefs(self, tmp_path):
@@ -171,8 +171,8 @@ class TestKeyBindings:
             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."""
+    async def test_t_goes_to_today(self, tmp_path):
+        """Pressing t returns to today's live view (issue #91)."""
         from fenris.tui import FenrisTuiApp
 
         config_home = _make_prefs_dir(tmp_path)
@@ -180,14 +180,19 @@ class TestKeyBindings:
             app = FenrisTuiApp(store_path=tmp_path / "nonexistent.db")
             async with app.run_test() as pilot:
                 # Start at amber
-                assert app.theme == "fenris-amber"
+                assert app.theme == "fenris-chalktone"
 
-                # Press t to cycle
+                # Enter drill mode on the graph
+                graph = app.query_one("#usage-history")
+                graph.view_mode = "hourly"
+                graph.drill_day = "2026-09-30"
+
+                # Press t to go back to today
                 await pilot.press("t")
                 await pilot.pause()
 
-                # Should be nord or high_contrast now
-                assert app.theme in ("fenris-nord", "fenris-high-contrast")
+                # Should be back in daily mode
+                assert graph.view_mode == "daily"
 
     @pytest.mark.asyncio
     async def test_m_toggles_reduced_motion(self, tmp_path):
@@ -226,21 +231,23 @@ class TestPersistence:
     async def test_theme_survives_restart(self, tmp_path):
         """Theme preference persists across TUI restart."""
         from fenris.tui import FenrisTuiApp
+        from fenris.preferences import save_preferences
 
         config_home = _make_prefs_dir(tmp_path)
         with patch.dict(os.environ, {"XDG_CONFIG_HOME": str(config_home)}):
-            # First run: change theme
+            # First run: change theme via preferences API
             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"
+                save_preferences(theme="nord", reduced_motion=False)
+                app1._current_theme_name = "nord"
+                app1.theme = "fenris-nord"
+                theme_after = app1.theme
+                assert theme_after == "fenris-nord"
 
             # 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
+                assert app2.theme == theme_after
 
     @pytest.mark.asyncio
     async def test_reduced_motion_survives_restart(self, tmp_path):
@@ -375,7 +382,7 @@ class TestSafePersistence:
             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"
+                assert app.theme == "fenris-chalktone"
                 # Dashboard should be functional
                 headline = str(app.query_one("#headline-band").render())
                 assert headline is not None
@@ -394,7 +401,7 @@ class TestSafePersistence:
             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")
+                assert app.theme in ("fenris-chalktone", "fenris-amber", "fenris-nord", "fenris-high-contrast")
 
 
 # ---------------------------------------------------------------------------

tests/test_issue_92.py

@@ -0,0 +1,596 @@
+"""Tests for issue #92: Browse activity dates from the keyboard.
+
+Covers:
+- AC92-1: [ and ] select previous/next day, g opens date entry, t returns to today/live
+- AC92-2: Date entry accepts valid dates, reports errors, returns on cancel
+- AC92-3: Selecting a date obtains correct local-day evidence
+- AC92-4: Historical date, measurement, and context remain stable across refresh
+- AC92-5: t resolves to today/live, themes through discoverable control
+- AC92-6: Drill-down shows available data with distinguishable states
+- AC92-7: Keyboard actions verified from normal launch with headless driver
+- AC92-8: Equivalent clickable actions at 80x24 and constrained widths
+"""
+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.local_day import (
+    LocalDaySummary,
+    persist_local_day,
+    query_local_day_summary,
+)
+from fenris.tui import (
+    FenrisTuiApp,
+    HistoryGraph,
+    _RANGE_OPTIONS,
+    _RANGE_DEFAULT,
+)
+
+
+# ---------------------------------------------------------------------------
+# 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"):
+    conn.execute(
+        "INSERT INTO controller_segments "
+        "(opened_at, identity_key, identity_degraded, subnqn, sn, mn, fr, vid, ssvid, transport) "
+        "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)",
+        (opened_at, identity_key, False, "nqn.test", "SN123",
+         "Samsung SSD 970 EVO Plus 1TB", "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 _open_period(conn, start="2026-09-01T00:00:00+00:00"):
+    ensure_period_open(conn, datetime.fromisoformat(start))
+
+
+def _insert_local_day(conn, local_date, tz_name="UTC", tz_offset="+00:00",
+                       bw=300, br=130, complete=True):
+    summary = LocalDaySummary(
+        local_date=local_date,
+        tz_name=tz_name,
+        tz_offset=tz_offset,
+        utc_start=f"{local_date}T00:00:00+00:00",
+        utc_end=f"{(datetime.fromisoformat(local_date) + timedelta(days=1)).strftime('%Y-%m-%d')}T00:00:00+00:00",
+        bytes_written=bw,
+        bytes_read=br,
+        coverage=0.95,
+        sample_count=24,
+        complete=complete,
+    )
+    persist_local_day(conn, summary)
+    conn.commit()
+
+
+def _setup_store(tmp_path, n_days=30, today=None):
+    """Create a store with n_days of data and return (conn, clock)."""
+    if today is None:
+        today = _clock()
+    conn = init_store(tmp_path / "test.db")
+    _insert_segment(conn)
+    _open_period(conn)
+    for i in range(n_days):
+        d = (today - timedelta(days=n_days - 1 - i)).strftime("%Y-%m-%d")
+        _insert_day(conn, d)
+    return conn, today
+
+
+def _make_app(tmp_path, clock=None):
+    """Create a FenrisTuiApp with the clock mocked to *clock*.
+
+    Returns (app, patcher) - caller must keep patcher alive during the test.
+    """
+    if clock is None:
+        clock = _clock()
+    from unittest.mock import patch
+    import fenris.tui as tui_mod
+    from datetime import datetime as _real_datetime
+
+    class MockDatetime(_real_datetime):
+        @classmethod
+        def now(cls, tz=None):
+            return clock
+
+    mock_dt = MockDatetime
+
+    patcher = patch.object(tui_mod, "datetime", mock_dt)
+    patcher.start()
+    app = FenrisTuiApp(store_path=tmp_path / "test.db", refresh_interval_s=999)
+    return app, patcher
+
+
+# ---------------------------------------------------------------------------
+# AC92-1: Keyboard bindings exist
+# ---------------------------------------------------------------------------
+
+class TestBindingExistence:
+    def test_open_square_bracket_binding(self, tmp_path):
+        """The [ binding exists for previous day navigation."""
+        app = FenrisTuiApp(store_path=tmp_path / "test.db")
+        binding_keys = {b.key for b in app.BINDINGS}
+        assert "left_square_bracket" in binding_keys
+
+    def test_close_square_bracket_binding(self, tmp_path):
+        """The ] binding exists for next day navigation."""
+        app = FenrisTuiApp(store_path=tmp_path / "test.db")
+        binding_keys = {b.key for b in app.BINDINGS}
+        assert "right_square_bracket" in binding_keys
+
+    def test_g_binding_exists(self, tmp_path):
+        """The g binding exists for date entry."""
+        app = FenrisTuiApp(store_path=tmp_path / "test.db")
+        binding_keys = {b.key for b in app.BINDINGS}
+        assert "g" in binding_keys
+
+    def test_t_binding_is_today(self, tmp_path):
+        """The t binding maps to action_today, not a theme action."""
+        app = FenrisTuiApp(store_path=tmp_path / "test.db")
+        t_binding = next(b for b in app.BINDINGS if b.key == "t")
+        assert "today" in t_binding.action.lower()
+
+    def test_pause_resume_quit_bindings_exist(self, tmp_path):
+        """Existing bindings are preserved."""
+        app = FenrisTuiApp(store_path=tmp_path / "test.db")
+        binding_keys = {b.key for b in app.BINDINGS}
+        assert "p" in binding_keys  # pause
+        assert "r" in binding_keys  # resume
+        assert "q" in binding_keys  # quit
+        assert "d" in binding_keys  # disclosures
+        assert "m" in binding_keys  # motion toggle
+
+
+# ---------------------------------------------------------------------------
+# AC92-1: Bracket navigation from normal launch
+# ---------------------------------------------------------------------------
+
+class TestBracketNavigation:
+    @pytest.mark.asyncio
+    async def test_right_bracket_advances_day(self, tmp_path):
+        """The ] key moves to the next (newer) day when not at the end."""
+        conn, clock = _setup_store(tmp_path, n_days=14)
+        conn.close()
+
+        app = FenrisTuiApp(store_path=tmp_path / "test.db", refresh_interval_s=999)
+        async with app.run_test(size=(100, 40)) as pilot:
+            await pilot.pause()
+            graph = app.query_one("#usage-history")
+            # Move to an older day first so ] can advance
+            for _ in range(3):
+                await pilot.press("left_square_bracket")
+            day_before = graph._day_data[graph.selected_index].get("day")
+
+            await pilot.press("right_square_bracket")
+            day_after = graph._day_data[graph.selected_index].get("day")
+            # ] should move to a newer day (closer to today)
+            assert day_after > day_before
+
+    @pytest.mark.asyncio
+    async def test_left_bracket_goes_to_previous_day(self, tmp_path):
+        """The [ key moves to the previous (older) day."""
+        conn, clock = _setup_store(tmp_path, n_days=14)
+        conn.close()
+
+        app = FenrisTuiApp(store_path=tmp_path / "test.db", refresh_interval_s=999)
+        async with app.run_test(size=(100, 40)) as pilot:
+            await pilot.pause()
+            graph = app.query_one("#usage-history")
+            day_before = graph._day_data[graph.selected_index].get("day")
+
+            await pilot.press("left_square_bracket")
+            day_after = graph._day_data[graph.selected_index].get("day")
+            # [ should move to an older day (further from today)
+            assert day_after < day_before
+
+    @pytest.mark.asyncio
+    async def test_bracket_navigates_outside_visible_range(self, tmp_path):
+        """[ beyond the current range shifts the visible window."""
+        app_clock = _clock()
+        conn, clock = _setup_store(tmp_path, n_days=30, today=app_clock)
+        conn.close()
+
+        app, patcher = _make_app(tmp_path, clock=app_clock)
+        try:
+            async with app.run_test(size=(100, 40)) as pilot:
+                await pilot.pause()
+                graph = app.query_one("#usage-history")
+                assert graph.range_days == _RANGE_DEFAULT
+
+                # Navigate to oldest day by pressing [ many times
+                for _ in range(29):
+                    await pilot.press("left_square_bracket")
+
+                # Graph should now show a range that includes the oldest day
+                assert graph.selected_index >= 0
+                selected_day = graph._day_data[graph.selected_index].get("day")
+                oldest_day = (app_clock - timedelta(days=29)).strftime("%Y-%m-%d")
+                assert selected_day == oldest_day
+        finally:
+            patcher.stop()
+
+    @pytest.mark.asyncio
+    async def test_bracket_at_boundary_does_not_move(self, tmp_path):
+        """] at the last day does not move the selection."""
+        conn, clock = _setup_store(tmp_path, n_days=14)
+        conn.close()
+
+        app = FenrisTuiApp(store_path=tmp_path / "test.db", refresh_interval_s=999)
+        async with app.run_test(size=(100, 40)) as pilot:
+            await pilot.pause()
+            graph = app.query_one("#usage-history")
+            initial_idx = graph.selected_index
+
+            await pilot.press("right_square_bracket")
+            assert graph.selected_index == initial_idx
+
+
+# ---------------------------------------------------------------------------
+# AC92-1: Arrow keys inspect the selected view
+# ---------------------------------------------------------------------------
+
+class TestArrowInspection:
+    @pytest.mark.asyncio
+    async def test_arrow_keys_still_work_in_daily_view(self, tmp_path):
+        """Arrow keys move the selection within the visible daily view."""
+        conn, clock = _setup_store(tmp_path, n_days=14)
+        conn.close()
+
+        app = FenrisTuiApp(store_path=tmp_path / "test.db", refresh_interval_s=999)
+        async with app.run_test(size=(100, 40)) as pilot:
+            await pilot.pause()
+            graph = app.query_one("#usage-history")
+            await pilot.press("v", "v")
+            graph.focus()
+            await pilot.pause()
+            day_before = graph._day_data[graph.selected_index].get("day")
+
+            await pilot.press("left")
+            day_after = graph._day_data[graph.selected_index].get("day")
+            assert day_after != day_before
+
+    @pytest.mark.asyncio
+    async def test_arrow_keys_inspect_hours_in_drill(self, tmp_path):
+        """Arrow keys navigate hours when in hourly drill-down."""
+        conn, clock = _setup_store(tmp_path, n_days=14)
+        conn.close()
+
+        app = FenrisTuiApp(store_path=tmp_path / "test.db", refresh_interval_s=999)
+        async with app.run_test(size=(100, 40)) as pilot:
+            await pilot.pause()
+            graph = app.query_one("#usage-history")
+            await pilot.press("v", "v")
+            await pilot.click("#usage-history")
+
+            # Enter drill-down
+            await pilot.press("enter")
+            assert graph.view_mode == "hourly"
+
+            # Arrow keys navigate hours
+            await pilot.press("left")
+            assert graph._hourly_selected >= 0
+
+
+# ---------------------------------------------------------------------------
+# AC92-1: t returns to today/live
+# ---------------------------------------------------------------------------
+
+class TestTodayBinding:
+    @pytest.mark.asyncio
+    async def test_t_returns_to_today_after_browsing(self, tmp_path):
+        """The t key returns to today's live view after browsing."""
+        conn, clock = _setup_store(tmp_path, n_days=14)
+        conn.close()
+
+        app = FenrisTuiApp(store_path=tmp_path / "test.db", refresh_interval_s=999)
+        async with app.run_test(size=(100, 40)) as pilot:
+            await pilot.pause()
+            graph = app.query_one("#usage-history")
+
+            # Browse to an older day using [
+            for _ in range(5):
+                await pilot.press("left_square_bracket")
+            browsed_day = graph._day_data[graph.selected_index].get("day")
+            today = clock.strftime("%Y-%m-%d")
+            assert browsed_day != today
+
+            # Press t to return to today
+            await pilot.press("t")
+            assert graph.selected_index == len(graph._day_data) - 1
+
+    @pytest.mark.asyncio
+    async def test_t_exits_hourly_drill(self, tmp_path):
+        """The t key exits hourly drill-down back to daily view."""
+        conn, clock = _setup_store(tmp_path, n_days=14)
+        conn.close()
+
+        app = FenrisTuiApp(store_path=tmp_path / "test.db", refresh_interval_s=999)
+        async with app.run_test(size=(100, 40)) as pilot:
+            await pilot.pause()
+            graph = app.query_one("#usage-history")
+            await pilot.press("v", "v")
+            await pilot.click("#usage-history")
+
+            # Enter drill
+            await pilot.press("enter")
+            assert graph.view_mode == "hourly"
+
+            # t returns to daily
+            await pilot.press("t")
+            assert graph.view_mode == "daily"
+
+
+# ---------------------------------------------------------------------------
+# AC92-2: Date entry screen
+# ---------------------------------------------------------------------------
+
+class TestDateEntry:
+    @pytest.mark.asyncio
+    async def test_g_opens_date_entry(self, tmp_path):
+        """The g key opens the date entry screen."""
+        conn, clock = _setup_store(tmp_path, n_days=14)
+        conn.close()
+
+        app = FenrisTuiApp(store_path=tmp_path / "test.db", refresh_interval_s=999)
+        async with app.run_test(size=(100, 40)) as pilot:
+            await pilot.pause()
+            await pilot.press("g")
+            await pilot.pause()
+            # Date picker should be pushed as a screen
+            assert len(app.screen_stack) > 1
+
+    @pytest.mark.asyncio
+    async def test_valid_date_navigates(self, tmp_path):
+        """Entering a valid date navigates to that day."""
+        app_clock = _clock()
+        conn, clock = _setup_store(tmp_path, n_days=30, today=app_clock)
+        conn.close()
+
+        app, patcher = _make_app(tmp_path, clock=app_clock)
+        try:
+            async with app.run_test(size=(100, 40)) as pilot:
+                await pilot.pause()
+                target_date = (app_clock - timedelta(days=5)).strftime("%Y-%m-%d")
+
+                # Simulate the date picker callback directly
+                app._go_to_date_callback(target_date)
+                await pilot.pause()
+
+                graph = app.query_one("#usage-history")
+                selected_day = graph._day_data[graph.selected_index].get("day")
+                assert selected_day == target_date
+        finally:
+            patcher.stop()
+
+    @pytest.mark.asyncio
+    async def test_invalid_date_shows_error(self, tmp_path):
+        """Entering an invalid date shows an error message."""
+        conn, clock = _setup_store(tmp_path, n_days=14)
+        conn.close()
+
+        app = FenrisTuiApp(store_path=tmp_path / "test.db", refresh_interval_s=999)
+        async with app.run_test(size=(100, 40)) as pilot:
+            await pilot.pause()
+            await pilot.press("g")
+            await pilot.pause()
+            await pilot.press("n", "o", "t", " ", "a", " ", "d", "a", "t", "e")
+            await pilot.press("enter")
+            await pilot.pause()
+            # Should remain on date picker (error shown, not dismissed)
+            assert len(app.screen_stack) > 1
+
+    @pytest.mark.asyncio
+    async def test_cancel_returns_to_prior(self, tmp_path):
+        """Pressing escape in date entry returns to the prior view."""
+        conn, clock = _setup_store(tmp_path, n_days=14)
+        conn.close()
+
+        app = FenrisTuiApp(store_path=tmp_path / "test.db", refresh_interval_s=999)
+        async with app.run_test(size=(100, 40)) as pilot:
+            await pilot.pause()
+            graph = app.query_one("#usage-history")
+            prior_idx = graph.selected_index
+
+            await pilot.press("g")
+            await pilot.pause()
+            await pilot.press("escape")
+            await pilot.pause()
+
+            # Should be back to the graph with the same selection
+            assert graph.selected_index == prior_idx
+
+
+# ---------------------------------------------------------------------------
+# AC92-3: Selecting a date obtains correct local-day evidence
+# ---------------------------------------------------------------------------
+
+class TestLocalDayEvidence:
+    @pytest.mark.asyncio
+    async def test_bracket_shows_local_day_for_selected_date(self, tmp_path):
+        """Navigating with brackets shows the local-day summary for that date."""
+        app_clock = _clock()
+        conn, clock = _setup_store(tmp_path, n_days=14, today=app_clock)
+        # Insert local-day data for a day within the 14-day range
+        target = (app_clock - timedelta(days=4)).strftime("%Y-%m-%d")
+        _insert_local_day(conn, target, bw=500, br=200)
+        conn.close()
+
+        app, patcher = _make_app(tmp_path, clock=app_clock)
+        try:
+            async with app.run_test(size=(100, 40)) as pilot:
+                await pilot.pause()
+                graph = app.query_one("#usage-history")
+
+                # Navigate to the target day
+                for _ in range(4):
+                    await pilot.press("left_square_bracket")
+                await pilot.pause()
+
+                local_day = app.query_one("#local-day")
+                text = str(local_day.render())
+                assert target in text
+        finally:
+            patcher.stop()
+
+    @pytest.mark.asyncio
+    async def test_date_picker_shows_local_day(self, tmp_path):
+        """Picking a date via the date picker shows its local-day summary."""
+        conn, clock = _setup_store(tmp_path, n_days=14)
+        target = (clock - timedelta(days=10)).strftime("%Y-%m-%d")
+        _insert_local_day(conn, target, bw=100, br=50)
+        conn.close()
+
+        app = FenrisTuiApp(store_path=tmp_path / "test.db", refresh_interval_s=999)
+        async with app.run_test(size=(100, 40)) as pilot:
+            await pilot.pause()
+            # Simulate the date picker callback directly
+            app._go_to_date_callback(target)
+            await pilot.pause()
+
+            local_day = app.query_one("#local-day")
+            text = str(local_day.render())
+            assert target in text
+
+
+# ---------------------------------------------------------------------------
+# AC92-4: Browsing stability across background refresh
+# ---------------------------------------------------------------------------
+
+class TestBrowsingStability:
+    @pytest.mark.asyncio
+    async def test_selection_stable_across_refresh(self, tmp_path):
+        """Browsing selection is preserved when background refresh fires."""
+        conn, clock = _setup_store(tmp_path, n_days=14)
+        conn.close()
+
+        app = FenrisTuiApp(store_path=tmp_path / "test.db", refresh_interval_s=0.1)
+        async with app.run_test(size=(100, 40)) as pilot:
+            await pilot.pause()
+            graph = app.query_one("#usage-history")
+
+            # Browse to a specific day
+            for _ in range(3):
+                await pilot.press("right_square_bracket")
+            browsed_day = graph._day_data[graph.selected_index].get("day")
+
+            # Wait for at least one refresh tick
+            import asyncio
+            await asyncio.sleep(0.3)
+            await pilot.pause()
+
+            # Selection should be preserved
+            assert graph.selected_index >= 0
+            assert graph._day_data[graph.selected_index].get("day") == browsed_day
+
+    @pytest.mark.asyncio
+    async def test_navigate_away_does_not_jump_on_refresh(self, tmp_path):
+        """After navigating away from today, refresh does not jump back."""
+        conn, clock = _setup_store(tmp_path, n_days=14)
+        conn.close()
+
+        app = FenrisTuiApp(store_path=tmp_path / "test.db", refresh_interval_s=0.1)
+        async with app.run_test(size=(100, 40)) as pilot:
+            await pilot.pause()
+            graph = app.query_one("#usage-history")
+
+            # Browse to older day using [
+            for _ in range(5):
+                await pilot.press("left_square_bracket")
+
+            browsed_day = graph._day_data[graph.selected_index].get("day")
+            today = clock.strftime("%Y-%m-%d")
+            assert browsed_day != today
+
+            # Wait for refresh
+            import asyncio
+            await asyncio.sleep(0.3)
+            await pilot.pause()
+
+            # Should NOT jump back to today
+            selected_day = graph._day_data[graph.selected_index].get("day")
+            assert selected_day != today
+
+
+# ---------------------------------------------------------------------------
+# AC92-6: Drill-down shows available data
+# ---------------------------------------------------------------------------
+
+class TestDrillDownData:
+    @pytest.mark.asyncio
+    async def test_drill_down_shows_loading_then_data(self, tmp_path):
+        """Drill-down transitions from loading to actual data."""
+        conn, clock = _setup_store(tmp_path, n_days=14)
+        conn.close()
+
+        app = FenrisTuiApp(store_path=tmp_path / "test.db", refresh_interval_s=999)
+        async with app.run_test(size=(100, 40)) as pilot:
+            await pilot.pause()
+            graph = app.query_one("#usage-history")
+            await pilot.press("v", "v")
+            await pilot.click("#usage-history")
+
+            # Enter drill-down
+            await pilot.press("enter")
+            assert graph.view_mode == "hourly"
+
+            # After drill callback, data should be populated
+            # (empty since we have no hour_observations)
+            assert graph.view_mode == "hourly"
+
+
+# ---------------------------------------------------------------------------
+# AC92-8: Constrained width behavior
+# ---------------------------------------------------------------------------
+
+class TestConstrainedWidth:
+    @pytest.mark.asyncio
+    async def test_bracket_navigation_works_at_80x24(self, tmp_path):
+        """Date navigation works at minimum 80x24 terminal size."""
+        conn, clock = _setup_store(tmp_path, n_days=14)
+        conn.close()
+
+        app = FenrisTuiApp(store_path=tmp_path / "test.db", refresh_interval_s=999)
+        async with app.run_test(size=(80, 24)) as pilot:
+            await pilot.pause()
+            graph = app.query_one("#usage-history")
+            day_before = graph._day_data[graph.selected_index].get("day")
+
+            await pilot.press("left_square_bracket")
+            day_after = graph._day_data[graph.selected_index].get("day")
+            assert day_after < day_before
+
+    @pytest.mark.asyncio
+    async def test_g_opens_date_entry_at_80x24(self, tmp_path):
+        """Date entry opens at minimum terminal size."""
+        conn, clock = _setup_store(tmp_path, n_days=14)
+        conn.close()
+
+        app = FenrisTuiApp(store_path=tmp_path / "test.db", refresh_interval_s=999)
+        async with app.run_test(size=(80, 24)) as pilot:
+            await pilot.pause()
+            await pilot.press("g")
+            await pilot.pause()
+            assert len(app.screen_stack) > 1

tests/test_issue_93.py

@@ -0,0 +1,603 @@
+"""Lifecycle tests for local-day history after detail expires (issue #93).
+
+Verifies the full lifecycle: raw samples collected, local-day summaries
+persisted, raw samples pruned after 14 days, and aged local-day summaries
+remain queryable with correct timezone, boundaries, and evidence-limit
+metadata.
+
+Seams:
+- Write side: collector.run_collection() → local_day derivation → persist
+- Pruning: prune_old_samples() removes raw samples but preserves local_days
+- Read side: query_local_day_history() returns entries with evidence flags
+- Repair: repair_derivation() does not touch existing local_days
+"""
+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.store import init_store, SCHEMA_VERSION
+from fenris.local_day import (
+    derive_local_day_summary,
+    persist_local_day,
+    query_local_day_summary,
+    query_local_day_history,
+    LocalDaySummary,
+    LocalDayHistoryEntry,
+    _is_detail_available,
+)
+from fenris.pruning import prune_old_samples, RAW_SAMPLE_RETENTION_DAYS
+from fenris.repair import repair_derivation
+from fenris.monitoring_periods import ensure_period_open, close_period
+
+
+# ---------------------------------------------------------------------------
+# Fixtures
+# ---------------------------------------------------------------------------
+
+def _make_smartctl(duw: int, dur: 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,
+            "data_units_read": dur, "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_tree(tmp_path: Path) -> Path:
+    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
+
+
+class _Clock:
+    def __init__(self, initial: datetime):
+        self.now = initial
+    def utcnow(self):
+        return self.now
+
+
+def _insert_hour(conn, hour_iso, bw=0, br=0, sample_count=1,
+                 active=3600, idle=0, powered_off=0, unknown=0):
+    """Insert a UTC hour observation."""
+    known = active + idle + powered_off
+    coverage = known / 3600.0
+    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, active, idle, powered_off, unknown, bw, br, sample_count, coverage),
+    )
+    conn.commit()
+
+
+def _insert_sample(conn, ts_iso, bw=0, br=0, device="/dev/nvme0"):
+    """Insert a raw sample."""
+    conn.execute(
+        "INSERT INTO samples (ts, device, data_units_written, data_units_read, "
+        " bytes_written, bytes_read, percentage_used) VALUES (?, ?, 0, 0, ?, ?, 0)",
+        (ts_iso, device, bw, br),
+    )
+    conn.commit()
+
+
+# ---------------------------------------------------------------------------
+# AC1: Advance through 14-day boundary, detail expires, summaries remain
+# ---------------------------------------------------------------------------
+
+class TestDetailExpiresSummariesRemain:
+    """AC1: After 14-day pruning, local-day summaries survive."""
+
+    def test_local_days_survive_sample_pruning(self, tmp_path):
+        """Local-day summaries persist after raw samples are pruned."""
+        conn = init_store(tmp_path / "obs.db")
+        now = datetime(2026, 10, 1, 12, 0, 0, tzinfo=timezone.utc)
+
+        # Create local-day summaries for dates spanning the 14-day boundary
+        # Day 1: 15 days ago (detail should be pruned)
+        old_summary = LocalDaySummary(
+            local_date="2026-09-16", tz_name="UTC", tz_offset="+00:00",
+            utc_start="2026-09-16T00:00:00+00:00",
+            utc_end="2026-09-17T00:00:00+00:00",
+            bytes_written=1000, bytes_read=500,
+            coverage=0.8, sample_count=10, complete=True,
+        )
+        persist_local_day(conn, old_summary)
+
+        # Day 2: 10 days ago (detail should be retained)
+        recent_summary = LocalDaySummary(
+            local_date="2026-09-21", tz_name="UTC", tz_offset="+00:00",
+            utc_start="2026-09-21T00:00:00+00:00",
+            utc_end="2026-09-22T00:00:00+00:00",
+            bytes_written=2000, bytes_read=800,
+            coverage=0.9, sample_count=15, complete=True,
+        )
+        persist_local_day(conn, recent_summary)
+
+        # Insert raw samples (old and recent)
+        _insert_sample(conn, "2026-09-16T10:00:00+00:00", bw=500, br=200)
+        _insert_sample(conn, "2026-09-16T10:05:00+00:00", bw=1000, br=500)
+        _insert_sample(conn, "2026-09-21T10:00:00+00:00", bw=1000, br=400)
+        _insert_sample(conn, "2026-09-21T10:05:00+00:00", bw=2000, br=800)
+
+        # Run pruning
+        pruned = prune_old_samples(conn, now, retention_days=14)
+
+        # The handcrafted totals lack replacement provenance, so retain samples.
+        assert pruned == 0
+
+        # Local-day summaries must still be queryable
+        old_result = query_local_day_summary(conn, "2026-09-16")
+        assert old_result is not None
+        assert old_result["bytes_written"] == 1000
+        assert old_result["bytes_read"] == 500
+
+        recent_result = query_local_day_summary(conn, "2026-09-21")
+        assert recent_result is not None
+        assert recent_result["bytes_written"] == 2000
+
+        conn.close()
+
+    def test_history_query_shows_evidence_limits(self, tmp_path):
+        """History entries annotate detail-availability correctly."""
+        conn = init_store(tmp_path / "obs.db")
+        now = datetime(2026, 10, 1, 12, 0, 0, tzinfo=timezone.utc)
+
+        # Old summary (detail pruned)
+        old = LocalDaySummary(
+            local_date="2026-09-16", tz_name="UTC", tz_offset="+00:00",
+            utc_start="2026-09-16T00:00:00+00:00",
+            utc_end="2026-09-17T00:00:00+00:00",
+            bytes_written=1000, bytes_read=500,
+            coverage=0.8, sample_count=10, complete=True,
+        )
+        persist_local_day(conn, old)
+
+        # Recent summary (detail available)
+        recent = LocalDaySummary(
+            local_date="2026-09-21", tz_name="UTC", tz_offset="+00:00",
+            utc_start="2026-09-21T00:00:00+00:00",
+            utc_end="2026-09-22T00:00:00+00:00",
+            bytes_written=2000, bytes_read=800,
+            coverage=0.9, sample_count=15, complete=True,
+        )
+        persist_local_day(conn, recent)
+
+        # Insert a recent sample (no old samples → old detail not available)
+        _insert_sample(conn, "2026-09-21T10:00:00+00:00", bw=1000, br=400)
+
+        # Query history
+        entries = query_local_day_history(conn, "2026-09-16", "2026-09-21", now)
+        assert len(entries) == 2
+
+        old_entry = next(e for e in entries if e.local_date == "2026-09-16")
+        assert old_entry.detail_available is False
+        assert old_entry.bytes_written == 1000
+
+        recent_entry = next(e for e in entries if e.local_date == "2026-09-21")
+        assert recent_entry.detail_available is True
+        assert recent_entry.bytes_written == 2000
+
+        conn.close()
+
+
+# ---------------------------------------------------------------------------
+# AC2: Preserve summaries and boundary evidence before pruning
+# ---------------------------------------------------------------------------
+
+class TestBoundaryPreservation:
+    """AC2: Summaries and boundary evidence preserved before pruning."""
+
+    def test_boundary_anchor_not_pruned_when_needed(self, tmp_path):
+        """Raw samples needed as boundary anchors are retained."""
+        conn = init_store(tmp_path / "obs.db")
+        now = datetime(2026, 10, 1, 12, 0, 0, tzinfo=timezone.utc)
+
+        # Old sample before cutoff, recent sample after cutoff
+        # The old sample is a boundary anchor
+        _insert_sample(conn, "2026-09-16T23:55:00+00:00", bw=100)
+        _insert_sample(conn, "2026-09-17T12:30:00+00:00", bw=200)
+
+        pruned = prune_old_samples(conn, now, retention_days=14)
+
+        # Boundary anchor should be retained
+        cursor = conn.execute(
+            "SELECT COUNT(*) FROM samples WHERE ts = '2026-09-16T23:55:00+00:00'"
+        )
+        assert cursor.fetchone()[0] == 1
+        conn.close()
+
+
+# ---------------------------------------------------------------------------
+# AC3: Aged summaries retain timezone after system-timezone change
+# ---------------------------------------------------------------------------
+
+class TestTimezonePreservation:
+    """AC3: Historical summaries retain recorded timezone after TZ change."""
+
+    def test_timezone_survives_pruning(self, tmp_path):
+        """Old summary in Asia/Kolkata retains its timezone after pruning."""
+        conn = init_store(tmp_path / "obs.db")
+        now = datetime(2026, 10, 1, 12, 0, 0, tzinfo=timezone.utc)
+
+        # Old summary in Asia/Kolkata
+        old = LocalDaySummary(
+            local_date="2026-09-16", tz_name="Asia/Kolkata", tz_offset="+05:30",
+            utc_start="2026-09-15T18:30:00+00:00",
+            utc_end="2026-09-16T18:30:00+00:00",
+            bytes_written=3000, bytes_read=1200,
+            coverage=0.7, sample_count=8, complete=False,
+        )
+        persist_local_day(conn, old)
+
+        # Prune
+        prune_old_samples(conn, now, retention_days=14)
+
+        # Summary must retain its timezone
+        result = query_local_day_summary(conn, "2026-09-16")
+        assert result is not None
+        assert result["tz_name"] == "Asia/Kolkata"
+        assert result["tz_offset"] == "+05:30"
+        # UTC boundaries are preserved (not rewritten)
+        assert result["utc_start"] == "2026-09-15T18:30:00+00:00"
+        assert result["utc_end"] == "2026-09-16T18:30:00+00:00"
+        conn.close()
+
+    def test_history_entry_shows_tz_after_pruning(self, tmp_path):
+        """History entry for aged summary shows correct timezone info."""
+        conn = init_store(tmp_path / "obs.db")
+        now = datetime(2026, 10, 1, 12, 0, 0, tzinfo=timezone.utc)
+
+        old = LocalDaySummary(
+            local_date="2026-09-16", tz_name="America/New_York", tz_offset="-04:00",
+            utc_start="2026-09-16T04:00:00+00:00",
+            utc_end="2026-09-17T04:00:00+00:00",
+            bytes_written=5000, bytes_read=2000,
+            coverage=0.6, sample_count=5, complete=False,
+        )
+        persist_local_day(conn, old)
+
+        entries = query_local_day_history(conn, "2026-09-16", "2026-09-16", now)
+        assert len(entries) == 1
+        entry = entries[0]
+        assert entry.tz_name == "America/New_York"
+        assert entry.tz_offset == "-04:00"
+        assert entry.utc_start == "2026-09-16T04:00:00+00:00"
+        assert entry.detail_available is False
+        conn.close()
+
+
+# ---------------------------------------------------------------------------
+# AC4: Legacy UTC summaries without local-day total remain incomplete
+# ---------------------------------------------------------------------------
+
+class TestLegacyDataHandling:
+    """AC4: Legacy UTC summaries that can't establish local-day total."""
+
+    def test_incomplete_legacy_labelled_correctly(self, tmp_path):
+        """Legacy summary without full evidence is labelled incomplete."""
+        conn = init_store(tmp_path / "obs.db")
+        now = datetime(2026, 10, 1, 12, 0, 0, tzinfo=timezone.utc)
+
+        # Simulate a legacy summary that can't establish a full local-day total
+        legacy = LocalDaySummary(
+            local_date="2026-09-16", tz_name="UTC", tz_offset="+00:00",
+            utc_start="2026-09-16T00:00:00+00:00",
+            utc_end="2026-09-17T00:00:00+00:00",
+            bytes_written=500, bytes_read=200,
+            coverage=0.3, sample_count=3, complete=False,
+        )
+        persist_local_day(conn, legacy)
+
+        result = query_local_day_summary(conn, "2026-09-16")
+        assert result is not None
+        assert result["complete"] is False
+        assert result["coverage"] == pytest.approx(0.3, abs=0.01)
+        conn.close()
+
+
+# ---------------------------------------------------------------------------
+# AC5: Migration, pruning, and repair are interruption-safe and idempotent
+# ---------------------------------------------------------------------------
+
+class TestIdempotencySafety:
+    """AC5: Operations are idempotent and interruption-safe."""
+
+    def test_repeated_pruning_no_side_effects(self, tmp_path):
+        """Running pruning multiple times produces the same result."""
+        conn = init_store(tmp_path / "obs.db")
+        now = datetime(2026, 10, 1, 12, 0, 0, tzinfo=timezone.utc)
+
+        # Create a local-day summary
+        summary = LocalDaySummary(
+            local_date="2026-09-16", tz_name="UTC", tz_offset="+00:00",
+            utc_start="2026-09-16T00:00:00+00:00",
+            utc_end="2026-09-17T00:00:00+00:00",
+            bytes_written=1000, bytes_read=500,
+            coverage=0.8, sample_count=10, complete=True,
+        )
+        persist_local_day(conn, summary)
+        _insert_sample(conn, "2026-09-16T10:00:00+00:00", bw=500)
+        _insert_sample(conn, "2026-09-16T10:05:00+00:00", bw=1000)
+
+        # Prune twice
+        prune_old_samples(conn, now, retention_days=14)
+        prune_old_samples(conn, now, retention_days=14)
+
+        # Local-day summary unchanged
+        result = query_local_day_summary(conn, "2026-09-16")
+        assert result is not None
+        assert result["bytes_written"] == 1000
+        conn.close()
+
+    def test_repair_does_not_touch_local_days(self, tmp_path):
+        """Repair derivation does not modify existing local_days entries."""
+        conn = init_store(tmp_path / "obs.db")
+
+        # Create a local-day summary
+        summary = LocalDaySummary(
+            local_date="2026-09-16", tz_name="UTC", tz_offset="+00:00",
+            utc_start="2026-09-16T00:00:00+00:00",
+            utc_end="2026-09-17T00:00:00+00:00",
+            bytes_written=1000, bytes_read=500,
+            coverage=0.8, sample_count=10, complete=True,
+        )
+        persist_local_day(conn, summary)
+
+        # Run repair (should not touch local_days)
+        result = repair_derivation(conn)
+        assert result.ok is True
+
+        # Local-day summary unchanged
+        stored = query_local_day_summary(conn, "2026-09-16")
+        assert stored is not None
+        assert stored["bytes_written"] == 1000
+        assert stored["bytes_read"] == 500
+        conn.close()
+
+
+# ---------------------------------------------------------------------------
+# AC6: Volume conservation — no double counting of midnight-spanning bytes
+# ---------------------------------------------------------------------------
+
+class TestVolumeConservation:
+    """AC6: UTC-hour totals never become fabricated local-day totals."""
+
+    def test_hourly_bytes_are_unavailable_at_local_precision(self, tmp_path):
+        """UTC-day hour bytes cannot be split across local-day boundaries."""
+        conn = init_store(tmp_path / "obs.db")
+
+        # Insert hour observations that span midnight
+        # UTC hour 2026-09-16T23:00 contains midnight boundary
+        _insert_hour(conn, "2026-09-16T23:00:00+00:00", bw=100, br=50)
+        _insert_hour(conn, "2026-09-17T00:00:00+00:00", bw=200, br=80)
+
+        # Derive summaries for both days
+        clock_16 = datetime(2026, 9, 16, 12, 0, 0, tzinfo=timezone.utc)
+        summary_16 = derive_local_day_summary(conn, "UTC", clock_16)
+        assert summary_16 is not None
+
+        clock_17 = datetime(2026, 9, 17, 12, 0, 0, tzinfo=timezone.utc)
+        summary_17 = derive_local_day_summary(conn, "UTC", clock_17)
+        assert summary_17 is not None
+
+        assert summary_16.bytes_written == 0
+        assert summary_17.bytes_written == 0
+        assert summary_16.activity_precision == "unavailable"
+        assert summary_17.activity_precision == "unavailable"
+        conn.close()
+
+
+# ---------------------------------------------------------------------------
+# AC7: Use existing retention/repair entry points with real stores
+# ---------------------------------------------------------------------------
+
+class TestExistingEntryPoints:
+    """AC7: Use existing entry points with real temporary stores."""
+
+    def test_prune_with_real_temp_store(self, tmp_path):
+        """Pruning works with a real temporary store."""
+        conn = init_store(tmp_path / "obs.db")
+        now = datetime(2026, 10, 1, 12, 0, 0, tzinfo=timezone.utc)
+
+        # Insert old and recent samples
+        for days_ago in range(1, 30):
+            ts = (now - timedelta(days=days_ago)).isoformat()
+            _insert_sample(conn, ts, bw=days_ago * 100)
+
+        pruned = prune_old_samples(conn, now, retention_days=14)
+        assert pruned == 0
+
+        cursor = conn.execute("SELECT COUNT(*) FROM samples")
+        assert cursor.fetchone()[0] == 29
+        conn.close()
+
+    def test_repair_with_real_temp_store(self, tmp_path):
+        """Repair works with a real temporary store."""
+        conn = init_store(tmp_path / "obs.db")
+
+        # Insert samples that need interval derivation
+        _insert_sample(conn, "2026-09-16T10:00:00+00:00", bw=100)
+        _insert_sample(conn, "2026-09-16T10:05:00+00:00", bw=200)
+
+        result = repair_derivation(conn)
+        assert result.ok is True
+        conn.close()
+
+
+# ---------------------------------------------------------------------------
+# AC8: User-visible transition from recent detail to older summaries
+# ---------------------------------------------------------------------------
+
+class TestUserVisibleTransition:
+    """AC8: Transition from recent detail to aged summaries."""
+
+    def test_recent_vs_aged_history_entries(self, tmp_path):
+        """Recent entries show detail_available=True, aged show False."""
+        conn = init_store(tmp_path / "obs.db")
+        now = datetime(2026, 10, 1, 12, 0, 0, tzinfo=timezone.utc)
+
+        # Create summaries for recent and aged dates
+        for days_ago, bw in [(5, 1000), (10, 2000), (15, 3000)]:
+            date = (now - timedelta(days=days_ago)).strftime("%Y-%m-%d")
+            utc_start = (now - timedelta(days=days_ago)).replace(
+                hour=0, minute=0, second=0, microsecond=0
+            ).isoformat()
+            utc_end = (now - timedelta(days=days_ago - 1)).replace(
+                hour=0, minute=0, second=0, microsecond=0
+            ).isoformat()
+
+            summary = LocalDaySummary(
+                local_date=date, tz_name="UTC", tz_offset="+00:00",
+                utc_start=utc_start, utc_end=utc_end,
+                bytes_written=bw, bytes_read=bw // 2,
+                coverage=0.8, sample_count=10, complete=True,
+            )
+            persist_local_day(conn, summary)
+
+        # Insert a recent sample (5 days ago)
+        _insert_sample(conn, (now - timedelta(days=5)).isoformat(), bw=500)
+
+        # Query full range
+        start = (now - timedelta(days=15)).strftime("%Y-%m-%d")
+        end = (now - timedelta(days=5)).strftime("%Y-%m-%d")
+        entries = query_local_day_history(conn, start, end, now)
+
+        assert len(entries) == 3
+
+        # Recent entry has detail
+        recent = next(e for e in entries if e.local_date == (now - timedelta(days=5)).strftime("%Y-%m-%d"))
+        assert recent.detail_available is True
+
+        # Aged entries do not have detail
+        aged_10 = next(e for e in entries if e.local_date == (now - timedelta(days=10)).strftime("%Y-%m-%d"))
+        assert aged_10.detail_available is False
+
+        aged_15 = next(e for e in entries if e.local_date == (now - timedelta(days=15)).strftime("%Y-%m-%d"))
+        assert aged_15.detail_available is False
+        conn.close()
+
+
+# ---------------------------------------------------------------------------
+# AC9: Document the 14-day detail vs indefinite-summary policy
+# ---------------------------------------------------------------------------
+
+class TestRetentionPolicyDocumentation:
+    """AC9: Module docstring documents the retention policy."""
+
+    def test_module_has_retention_policy_doc(self):
+        """The local_day module documents the 14-day vs indefinite policy."""
+        import fenris.local_day as ld
+        docstring = ld.__doc__
+        assert "14 day" in docstring.lower() or "fourteen" in docstring.lower()
+        assert "indefinite" in docstring.lower()
+        assert "retention" in docstring.lower()
+
+    def test_pruning_module_documents_local_days_preservation(self):
+        """The pruning module documents that local_days are preserved."""
+        import fenris.pruning as pr
+        docstring = pr.__doc__
+        assert "local_days" in docstring.lower() or "local day" in docstring.lower()
+        assert "preserved" in docstring.lower() or "never" in docstring.lower()
+
+
+# ---------------------------------------------------------------------------
+# Evidence-limit visibility
+# ---------------------------------------------------------------------------
+
+class TestEvidenceLimitVisibility:
+    """History entries expose evidence-availability metadata."""
+
+    def test_detail_available_flag_reflects_samples(self, tmp_path):
+        """detail_available is True only when samples exist within retention."""
+        conn = init_store(tmp_path / "obs.db")
+        now = datetime(2026, 10, 1, 12, 0, 0, tzinfo=timezone.utc)
+
+        # Summary for a date with no samples
+        no_samples = LocalDaySummary(
+            local_date="2026-09-16", tz_name="UTC", tz_offset="+00:00",
+            utc_start="2026-09-16T00:00:00+00:00",
+            utc_end="2026-09-17T00:00:00+00:00",
+            bytes_written=500, bytes_read=200,
+            coverage=0.4, sample_count=3, complete=False,
+        )
+        persist_local_day(conn, no_samples)
+
+        # Summary for a date with a recent sample
+        with_sample = LocalDaySummary(
+            local_date="2026-09-21", tz_name="UTC", tz_offset="+00:00",
+            utc_start="2026-09-21T00:00:00+00:00",
+            utc_end="2026-09-22T00:00:00+00:00",
+            bytes_written=1000, bytes_read=400,
+            coverage=0.9, sample_count=10, complete=True,
+        )
+        persist_local_day(conn, with_sample)
+        _insert_sample(conn, "2026-09-21T12:00:00+00:00", bw=500)
+
+        entries = query_local_day_history(conn, "2026-09-16", "2026-09-21", now)
+
+        no_samples_entry = next(e for e in entries if e.local_date == "2026-09-16")
+        assert no_samples_entry.detail_available is False
+
+        with_sample_entry = next(e for e in entries if e.local_date == "2026-09-21")
+        assert with_sample_entry.detail_available is True
+        conn.close()
+
+    def test_empty_history_range_returns_empty_list(self, tmp_path):
+        """Querying an empty date range returns an empty list."""
+        conn = init_store(tmp_path / "obs.db")
+        now = datetime(2026, 10, 1, 12, 0, 0, tzinfo=timezone.utc)
+
+        entries = query_local_day_history(conn, "2026-01-01", "2026-01-31", now)
+        assert entries == []
+        conn.close()
+
+    def test_history_entry_from_summary_factory(self, tmp_path):
+        """LocalDayHistoryEntry.from_summary creates entry from dict."""
+        summary = {
+            "local_date": "2026-09-16",
+            "tz_name": "UTC",
+            "tz_offset": "+00:00",
+            "utc_start": "2026-09-16T00:00:00+00:00",
+            "utc_end": "2026-09-17T00:00:00+00:00",
+            "bytes_written": 1000,
+            "bytes_read": 500,
+            "coverage": 0.8,
+            "sample_count": 10,
+            "complete": True,
+        }
+        entry = LocalDayHistoryEntry.from_summary(
+            summary, detail_available=True, derived_from_surviving=True
+        )
+        assert entry.local_date == "2026-09-16"
+        assert entry.detail_available is True
+        assert entry.derived_from_surviving is True
+        assert entry.bytes_written == 1000

tests/test_issue_97.py

@@ -0,0 +1,294 @@
+"""Pending publication behavior from issue #97."""
+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 import collector
+from fenris.projection import compute_projection
+from fenris.status import _query_drive_facts, get_status, read_status
+from fenris.status_composition import render_status_tui
+from fenris.store import init_store
+
+
+class FakeClock:
+    def __init__(self, now):
+        self.now = now
+
+    def utcnow(self):
+        return self.now
+
+
+@pytest.fixture
+def sysfs_fixture_tree(tmp_path):
+    ctrl_dir = tmp_path / "sys" / "class" / "nvme" / "nvme0"
+    ctrl_dir.mkdir(parents=True)
+    (ctrl_dir / "subsysnqn").write_text("nqn.test:drive\n")
+    (ctrl_dir / "model").write_text("Test NVMe\n")
+    (ctrl_dir / "serial").write_text("test-serial\n")
+    (ctrl_dir / "firmware_rev").write_text("1.0\n")
+    transport_dir = ctrl_dir / "transport"
+    transport_dir.mkdir()
+    (transport_dir / "trstring").write_text("pcie\n")
+    return tmp_path
+
+
+def _smartctl(unit_written, unit_read=500):
+    return {
+        "nvme_smart_health_information_log": {
+            "critical_warning": 0,
+            "temperature": 35,
+            "available_spare": 100,
+            "percentage_used": 5,
+            "data_units_written": unit_written,
+            "data_units_read": unit_read,
+            "power_on_hours": 100,
+        },
+        "user_capacity": {"bytes": 1_024_000_000_000},
+        "model_name": "Test NVMe",
+        "serial_number": "test-serial",
+        "firmware_version": "1.0",
+    }
+
+
+def _acquirer(sysfs_path, unit_written, unit_read=500):
+    return lambda: (_smartctl(unit_written, unit_read), sysfs_path)
+
+
+def _public_snapshot(store_path, clock_now):
+    with read_status(store_path, clock_now) as (conn, comp):
+        assert conn is not None
+        return {
+            "state": comp.state,
+            "freshness": comp.freshness,
+            "sample_count": comp.sample_count,
+            "day_count": comp.day_count,
+            "boot_enabled": comp.boot_enabled,
+            "timer_active": comp.timer_active,
+            "last_collect_ok": comp.last_collect_ok,
+            "latest_sample": tuple(conn.execute(
+                "SELECT ts, subnqn, mn, sn, fr, capacity_bytes, temperature_c, "
+                "available_spare, data_units_written, bytes_written, critical_warning, "
+                "media_errors, unsafe_shutdowns "
+                "FROM samples ORDER BY id DESC LIMIT 1"
+            ).fetchone()),
+            "drive_facts": tuple(_query_drive_facts(conn)),
+            "projection": repr(compute_projection(conn, clock_now)),
+            "segments": conn.execute("SELECT COUNT(*) FROM controller_segments").fetchone()[0],
+            "periods": conn.execute("SELECT COUNT(*) FROM monitoring_periods").fetchone()[0],
+            "hours": tuple(conn.execute(
+                "SELECT hour, bytes_written_delta, bytes_read_delta, sample_count "
+                "FROM hour_observations ORDER BY hour"
+            ).fetchall()),
+            "days": tuple(conn.execute(
+                "SELECT day, bytes_written_delta, bytes_read_delta "
+                "FROM day_aggregates ORDER BY day"
+            ).fetchall()),
+            "local_days": tuple(conn.execute(
+                "SELECT local_date, bytes_written, bytes_read, sample_count "
+                "FROM local_days ORDER BY local_date, tz_name"
+            ).fetchall()),
+            "pending": comp.pending_publication_count,
+        }
+
+
+def test_failed_publication_survives_restart_and_readers_keep_last_consistent_view(
+    tmp_path, sysfs_fixture_tree, monkeypatch
+):
+    """A failed derivation stays private, visible as pending, and replays in order."""
+    monkeypatch.setenv("TZ", "UTC")
+    service = {"boot_enabled": True, "timer_active": True, "last_collect_ok": True}
+    monkeypatch.setattr("fenris.status.query_service_state", lambda: service)
+    now = datetime.now(timezone.utc).replace(
+        minute=35, second=0, microsecond=0,
+    )
+    store_path = tmp_path / "observations.db"
+    config = {"device": "/dev/nvme0", "store_path": str(store_path)}
+    sysfs_path = sysfs_fixture_tree / "sys" / "class" / "nvme" / "nvme0"
+
+    for units, at in ((1000, now - timedelta(minutes=10)), (1010, now - timedelta(minutes=5))):
+        result = collector.run_collection(
+            config=config,
+            clock=FakeClock(at),
+            acquire=_acquirer(sysfs_path, units),
+        )
+        assert result["ok"] is True, result
+
+    previous = _public_snapshot(store_path, now)
+    baseline_cli = get_status(store_path, now, query_services=False, query_journal=False)
+    original_derive = collector.derive_hours_from_interval
+    reader_during_write = {}
+
+    def fail_derivation(conn, previous_sample, next_sample):
+        # Read while writer has inserted the unpublished sample but not committed.
+        with read_status(store_path, now, query_services=False) as (reader, comp):
+            assert reader is not None
+            reader_during_write["samples"] = reader.execute(
+                "SELECT COUNT(*) FROM samples"
+            ).fetchone()[0]
+            reader_during_write["pending"] = comp.pending_publication_count
+            reader_during_write["latest"] = tuple(reader.execute(
+                "SELECT data_units_written FROM samples ORDER BY id DESC LIMIT 1"
+            ).fetchone())
+        raise RuntimeError("injected non-invariant derivation failure")
+
+    monkeypatch.setattr(collector, "derive_hours_from_interval", fail_derivation)
+    failed = collector.run_collection(
+        config=config,
+        clock=FakeClock(now),
+        acquire=_acquirer(sysfs_path, 1025),
+    )
+    assert failed["ok"] is False
+    assert "injected non-invariant derivation failure" in failed["error"]
+    assert reader_during_write == {"samples": 2, "pending": 1, "latest": (1010,)}
+
+    after_failure = _public_snapshot(store_path, now)
+    assert {**after_failure, "pending": previous["pending"]} == previous
+    assert after_failure["pending"] == 1
+
+    cli_text = get_status(store_path, now, query_services=False, query_journal=False)
+    pending_fact = " · pending publication: 1 observation retained for retry"
+    assert pending_fact in cli_text
+    assert cli_text.replace(pending_fact, "", 1) == baseline_cli
+
+    with read_status(store_path, now) as (_, comp):
+        assert comp.state == previous["state"]
+        assert comp.boot_enabled is True
+        assert comp.timer_active is True
+        assert "pending publication: 1 observation retained for retry" in render_status_tui(comp).lower()
+
+    called = False
+
+    def should_wait_for_recovery():
+        nonlocal called
+        called = True
+        return _smartctl(1030), sysfs_path
+
+    monkeypatch.setattr(collector, "PENDING_PUBLICATION_LIMIT", 1)
+    blocked = collector.run_collection(
+        config=config,
+        clock=FakeClock(now + timedelta(minutes=5)),
+        acquire=should_wait_for_recovery,
+    )
+    assert blocked["ok"] is False
+    assert called is False
+    assert _public_snapshot(store_path, now)["pending"] == 1
+
+    monkeypatch.setattr(collector, "derive_hours_from_interval", original_derive)
+    monkeypatch.setenv("TZ", "Asia/Kolkata")
+    recovered = collector.run_collection(
+        config=config,
+        clock=FakeClock(now + timedelta(minutes=5)),
+        acquire=_acquirer(sysfs_path, 1040),
+    )
+    assert recovered["ok"] is True, recovered
+
+    conn = sqlite3.connect(store_path)
+    try:
+        assert conn.execute(
+            "SELECT data_units_written FROM samples ORDER BY id"
+        ).fetchall() == [(1000,), (1010,), (1025,), (1040,)]
+        assert conn.execute("SELECT COUNT(*) FROM pending_publications").fetchone()[0] == 0
+        assert conn.execute(
+            "SELECT SUM(bytes_written_delta) FROM day_aggregates"
+        ).fetchone()[0] == (1040 - 1000) * 512_000
+        assert conn.execute(
+            "SELECT sample_count FROM local_days WHERE tz_name = 'UTC'"
+        ).fetchone()[0] == 4
+        assert conn.execute(
+            "SELECT COUNT(*) FROM local_days WHERE tz_name = 'Asia/Kolkata'"
+        ).fetchone()[0] == 1
+    finally:
+        conn.close()
+
+
+def test_invalid_sample_writes_no_sample_segment_period_or_pending_row(tmp_path, sysfs_fixture_tree):
+    """Sample invariants run before staging or public monitoring changes."""
+    now = datetime.now(timezone.utc).replace(second=0, microsecond=0)
+    store_path = tmp_path / "observations.db"
+    config = {"device": "/dev/nvme0", "store_path": str(store_path)}
+    sysfs_path = sysfs_fixture_tree / "sys" / "class" / "nvme" / "nvme0"
+    result = collector.run_collection(
+        config=config,
+        clock=FakeClock(now),
+        acquire=_acquirer(sysfs_path, -1),
+    )
+
+    assert result["ok"] is False
+    assert result["error_type"] == "InvariantViolationError"
+    conn = sqlite3.connect(store_path)
+    try:
+        assert conn.execute("SELECT COUNT(*) FROM samples").fetchone()[0] == 0
+        assert conn.execute("SELECT COUNT(*) FROM controller_segments").fetchone()[0] == 0
+        assert conn.execute("SELECT COUNT(*) FROM monitoring_periods").fetchone()[0] == 0
+        assert conn.execute("SELECT COUNT(*) FROM pending_publications").fetchone()[0] == 0
+    finally:
+        conn.close()
+
+
+def test_pending_capacity_retries_before_skipping_acquisition(tmp_path, sysfs_fixture_tree, monkeypatch):
+    now = datetime.now(timezone.utc).replace(second=0, microsecond=0)
+    store_path = tmp_path / "observations.db"
+    config = {"device": "/dev/nvme0", "store_path": str(store_path)}
+    sysfs_path = sysfs_fixture_tree / "sys" / "class" / "nvme" / "nvme0"
+    first = collector.run_collection(
+        config=config,
+        clock=FakeClock(now - timedelta(minutes=5)),
+        acquire=_acquirer(sysfs_path, 1000),
+    )
+    assert first["ok"] is True, first
+
+    monkeypatch.setattr(collector, "PENDING_PUBLICATION_LIMIT", 1)
+
+    def fail_derivation(*_):
+        raise RuntimeError("derivation still unavailable")
+
+    monkeypatch.setattr(collector, "derive_hours_from_interval", fail_derivation)
+    failed = collector.run_collection(
+        config=config,
+        clock=FakeClock(now),
+        acquire=_acquirer(sysfs_path, 1010),
+    )
+    assert failed["ok"] is False
+    assert "capacity full (1 observations)" in failed["error"]
+
+    called = False
+
+    def must_not_acquire():
+        nonlocal called
+        called = True
+        return _smartctl(1020), sysfs_path
+
+    retry = collector.run_collection(
+        config=config,
+        clock=FakeClock(now + timedelta(minutes=5)),
+        acquire=must_not_acquire,
+    )
+    assert retry["ok"] is False
+    assert "capacity full (1 observations)" in retry["error"]
+    assert called is False
+
+
+def test_v3_readers_ignore_pending_table_until_store_migrates(tmp_path):
+    store_path = tmp_path / "observations.db"
+    conn = init_store(store_path)
+    conn.execute("DROP TABLE pending_publications")
+    conn.execute("PRAGMA user_version=3")
+    conn.commit()
+    conn.close()
+
+    with read_status(store_path, datetime.now(timezone.utc), query_services=False) as (reader, comp):
+        assert reader is not None
+        assert comp.store_fault is None
+        assert comp.pending_publication_count == 0
+
+    migrated = init_store(store_path)
+    try:
+        assert migrated.execute("PRAGMA user_version").fetchone()[0] == 6
+        assert migrated.execute("SELECT COUNT(*) FROM pending_publications").fetchone()[0] == 0
+    finally:
+        migrated.close()

tests/test_issue_99.py

@@ -0,0 +1,520 @@
+"""Historical local-day migration and repair acceptance tests for issue #99."""
+import sqlite3
+import sys
+from datetime import datetime, timezone
+from pathlib import Path
+
+import pytest
+
+sys.path.insert(0, str(Path(__file__).parent.parent / "src"))
+
+from fenris.local_day import (
+    query_local_day_summary,
+    record_local_activity_interval,
+)
+from fenris.status import read_status
+from fenris.store import init_store
+
+SOURCE_SCHEMA_VERSION = 5
+LOCAL_DATE = "2026-09-02"
+TIMEZONE = "Asia/Kolkata"
+UTC_START = "2026-09-01T18:30:00+00:00"
+UTC_END = "2026-09-02T18:30:00+00:00"
+
+
+def _legacy_store(path: Path) -> sqlite3.Connection:
+    """Build a v5 store with one old coarse local-day summary."""
+    conn = init_store(path)
+    conn.execute(
+        "INSERT INTO local_days "
+        "(local_date, tz_name, tz_offset, utc_start, utc_end, bytes_written, "
+        " bytes_read, coverage, sample_count, complete, activity_incomplete, "
+        " activity_precision) "
+        "VALUES (?, ?, '+05:30', ?, ?, 999999, 888888, 1.0, 24, 1, 0, 'legacy')",
+        (LOCAL_DATE, TIMEZONE, UTC_START, UTC_END),
+    )
+    conn.execute(
+        "INSERT INTO monitoring_periods (started_at, ended_at) VALUES (?, ?)",
+        (UTC_START, "2026-09-03T00:00:00+00:00"),
+    )
+    conn.execute(
+        "INSERT INTO controller_segments "
+        "(opened_at, identity_key, identity_degraded) VALUES (?, ?, 0)",
+        (UTC_START, "controller-a"),
+    )
+    conn.execute(
+        "INSERT INTO hour_observations "
+        "(hour, bytes_written_delta, bytes_read_delta, sample_count, coverage) "
+        "VALUES ('2026-09-02T00:00:00+00:00', 123, 45, 2, 1.0)"
+    )
+    conn.execute(
+        "INSERT INTO day_aggregates "
+        "(day, bytes_written_delta, bytes_read_delta, coverage) "
+        "VALUES ('2026-09-02', 678, 90, 1.0)"
+    )
+    conn.execute(
+        "INSERT INTO samples (ts, device, bytes_written, bytes_read, power_on_hours, "
+        " segment_id, local_tz) VALUES (?, '/dev/nvme0', 1000, 2000, 100, 1, ?)",
+        ("2026-09-01T19:00:00+00:00", TIMEZONE),
+    )
+    conn.execute(
+        "INSERT INTO samples (ts, device, bytes_written, bytes_read, power_on_hours, "
+        " segment_id, local_tz) VALUES (?, '/dev/nvme0', 11000, 5000, 115, 1, ?)",
+        ("2026-09-02T10:00:00+00:00", TIMEZONE),
+    )
+    conn.execute(f"PRAGMA user_version={SOURCE_SCHEMA_VERSION}")
+    conn.commit()
+    return conn
+
+
+def test_upgrade_rebuilds_legacy_day_from_samples_and_keeps_recorded_bounds(
+    tmp_path, monkeypatch,
+):
+    db = tmp_path / "legacy.db"
+    conn = _legacy_store(db)
+    conn.close()
+    monkeypatch.setenv("TZ", "UTC")
+
+    conn = init_store(db)
+    conn.close()
+
+    with read_status(
+        db, datetime(2026, 9, 4, tzinfo=timezone.utc), query_services=False,
+    ) as (reader, composition):
+        assert reader is not None
+        assert composition.store_fault is None
+        summary = query_local_day_summary(
+            reader, LOCAL_DATE, TIMEZONE,
+            datetime(2026, 9, 4, tzinfo=timezone.utc),
+        )
+        assert summary is not None
+        assert summary["local_date"] == LOCAL_DATE
+        assert summary["tz_name"] == TIMEZONE
+        assert summary["tz_offset"] == "+05:30"
+        assert summary["utc_start"] == UTC_START
+        assert summary["utc_end"] == UTC_END
+        assert summary["bytes_written"] == 10_000
+        assert summary["bytes_read"] == 3_000
+        assert summary["activity_precision"] == "measured"
+        assert summary["segments"] == [{
+            "segment_id": 1,
+            "bytes_written": 10_000,
+            "bytes_read": 3_000,
+            "activity_seconds": 54_000,
+            "activity_intervals": 1,
+        }]
+        assert summary["activity_state"] == "incomplete"
+        assert reader.execute(
+            "SELECT bytes_written_delta FROM hour_observations"
+        ).fetchone()[0] == 123
+        assert reader.execute(
+            "SELECT bytes_written_delta FROM day_aggregates"
+        ).fetchone()[0] == 678
+
+    conn = init_store(db)
+    conn.close()
+    with read_status(
+        db, datetime(2026, 9, 4, tzinfo=timezone.utc), query_services=False,
+    ) as (reader, _composition):
+        assert reader is not None
+        summary = query_local_day_summary(
+            reader, LOCAL_DATE, TIMEZONE,
+            datetime(2026, 9, 4, tzinfo=timezone.utc),
+        )
+        assert summary["bytes_written"] == 10_000
+        assert summary["bytes_read"] == 3_000
+
+
+def test_repair_rebuilds_legacy_local_day_once_across_restarts(tmp_path):
+    from fenris.repair import repair_derivation
+
+    db = tmp_path / "repair.db"
+    conn = _legacy_store(db)
+
+    first = repair_derivation(conn)
+    assert first.ok
+    summary = query_local_day_summary(
+        conn, LOCAL_DATE, TIMEZONE,
+        datetime(2026, 9, 4, tzinfo=timezone.utc),
+    )
+    assert summary["bytes_written"] == 10_000
+    assert summary["bytes_read"] == 3_000
+
+    conn.close()
+    conn = sqlite3.connect(db)
+    second = repair_derivation(conn)
+    assert second.ok
+    summary = query_local_day_summary(
+        conn, LOCAL_DATE, TIMEZONE,
+        datetime(2026, 9, 4, tzinfo=timezone.utc),
+    )
+    assert summary["bytes_written"] == 10_000
+    assert summary["bytes_read"] == 3_000
+    assert conn.execute(
+        "SELECT bytes_written, bytes_read, activity_intervals "
+        "FROM local_day_segment_totals"
+    ).fetchall() == [(10_000, 3_000, 1)]
+    conn.close()
+
+
+def test_interrupted_repair_keeps_local_day_rebuild_retryable(tmp_path):
+    from fenris.repair import repair_derivation
+
+    db = tmp_path / "repair-interrupted.db"
+    conn = _legacy_store(db)
+    conn.execute(
+        "CREATE TRIGGER interrupt_repair_local_rebuild "
+        "BEFORE INSERT ON local_day_segment_totals "
+        "BEGIN SELECT RAISE(ABORT, 'simulated repair interruption'); END"
+    )
+    conn.commit()
+
+    failed = repair_derivation(conn)
+    assert not failed.ok
+    assert query_local_day_summary(
+        conn, LOCAL_DATE, TIMEZONE,
+        datetime(2026, 9, 4, tzinfo=timezone.utc),
+    )["bytes_written"] is None
+    assert conn.execute(
+        "SELECT activity_precision, bytes_written FROM local_days"
+    ).fetchone() == ("legacy", 999_999)
+    conn.execute("DROP TRIGGER interrupt_repair_local_rebuild")
+    conn.commit()
+    conn.close()
+
+    conn = sqlite3.connect(db)
+    retried = repair_derivation(conn)
+    assert retried.ok
+    summary = query_local_day_summary(
+        conn, LOCAL_DATE, TIMEZONE,
+        datetime(2026, 9, 4, tzinfo=timezone.utc),
+    )
+    assert summary["bytes_written"] == 10_000
+    assert summary["bytes_read"] == 3_000
+    conn.close()
+
+
+def test_stale_repair_marker_does_not_block_crash_retry(tmp_path):
+    from fenris.repair import repair_derivation
+
+    conn = _legacy_store(tmp_path / "stale-repair.db")
+    conn.execute(
+        "INSERT OR REPLACE INTO store_metadata (key, value) "
+        "VALUES ('repair_in_progress', 'true')"
+    )
+    conn.commit()
+
+    result = repair_derivation(conn)
+
+    assert result.ok
+    assert conn.execute(
+        "SELECT value FROM store_metadata WHERE key = 'repair_in_progress'"
+    ).fetchone() == ("false",)
+    assert query_local_day_summary(
+        conn, LOCAL_DATE, TIMEZONE,
+        datetime(2026, 9, 4, tzinfo=timezone.utc),
+    )["bytes_written"] == 10_000
+    conn.close()
+
+
+def test_upgrade_uses_whole_utc_hours_but_skips_midnight_straddling_hours(
+    tmp_path,
+):
+    db = tmp_path / "coarse.db"
+    conn = _legacy_store(db)
+    conn.execute("DELETE FROM samples")
+    conn.execute(
+        "INSERT INTO hour_observations "
+        "(hour, bytes_written_delta, bytes_read_delta, sample_count, "
+        " active_seconds, coverage) "
+        "VALUES ('2026-09-01T18:00:00+00:00', 99999, 9999, 2, 3600, 1.0)"
+    )
+    conn.execute(
+        "INSERT INTO hour_observations "
+        "(hour, bytes_written_delta, bytes_read_delta, sample_count, "
+        " active_seconds, coverage) "
+        "VALUES ('2026-09-02T18:00:00+00:00', 88888, 8888, 2, 3600, 1.0)"
+    )
+    conn.commit()
+    conn.close()
+
+    conn = init_store(db)
+    summary = query_local_day_summary(
+        conn, LOCAL_DATE, TIMEZONE,
+        datetime(2026, 9, 4, tzinfo=timezone.utc),
+    )
+    assert summary["bytes_written"] == 123
+    assert summary["bytes_read"] == 45
+    assert summary["activity_precision"] == "coarse"
+    assert summary["activity_state"] == "incomplete"
+    assert summary["utc_start"] == UTC_START
+    assert summary["utc_end"] == UTC_END
+
+    conn.execute(
+        "INSERT INTO samples "
+        "(id, ts, device, bytes_written, bytes_read, segment_id, local_tz) "
+        "VALUES (10, '2026-09-02T12:00:00+00:00', '/dev/nvme0', 1000, 2000, 1, ?), "
+        "       (11, '2026-09-02T12:05:00+00:00', '/dev/nvme0', 2000, 2500, 1, ?)",
+        (TIMEZONE, TIMEZONE),
+    )
+    conn.commit()
+    assert record_local_activity_interval(
+        conn,
+        {
+            "id": 10, "ts": "2026-09-02T12:00:00+00:00",
+            "bytes_written": 1_000, "bytes_read": 2_000,
+            "local_tz": TIMEZONE,
+        },
+        {
+            "id": 11, "ts": "2026-09-02T12:05:00+00:00",
+            "bytes_written": 2_000, "bytes_read": 2_500,
+            "local_tz": TIMEZONE,
+        },
+        start_sample_id=10, end_sample_id=11, segment_id=1,
+    ) == "known"
+    summary = query_local_day_summary(
+        conn, LOCAL_DATE, TIMEZONE,
+        datetime(2026, 9, 4, tzinfo=timezone.utc),
+    )
+    assert summary["bytes_written"] == 1_000
+    assert summary["bytes_read"] == 500
+    assert summary["activity_precision"] == "measured"
+    assert summary["segments"] == [{
+        "segment_id": 1,
+        "bytes_written": 1_000,
+        "bytes_read": 500,
+        "activity_seconds": 300,
+        "activity_intervals": 1,
+    }]
+    conn.close()
+
+
+def test_upgrade_does_not_double_count_coarse_hours_in_overlapping_days(tmp_path):
+    db = tmp_path / "overlapping-coarse-days.db"
+    conn = _legacy_store(db)
+    conn.execute("DELETE FROM samples")
+    conn.execute(
+        "INSERT INTO local_days "
+        "(local_date, tz_name, tz_offset, utc_start, utc_end, bytes_written, "
+        " bytes_read, coverage, sample_count, complete, activity_precision) "
+        "VALUES ('2026-09-02', 'UTC', '+00:00', "
+        "'2026-09-02T00:00:00+00:00', '2026-09-03T00:00:00+00:00', "
+        "999999, 888888, 1.0, 24, 1, 'legacy')"
+    )
+    conn.commit()
+    conn.close()
+
+    conn = init_store(db)
+
+    for tz_name in (TIMEZONE, "UTC"):
+        summary = query_local_day_summary(
+            conn, LOCAL_DATE, tz_name,
+            datetime(2026, 9, 4, tzinfo=timezone.utc),
+        )
+        assert summary["bytes_written"] is None
+        assert summary["bytes_read"] is None
+        assert summary["activity_precision"] == "unavailable"
+        assert summary["activity_state"] == "unavailable"
+    assert conn.execute(
+        "SELECT bytes_written_delta, bytes_read_delta FROM hour_observations "
+        "WHERE hour = '2026-09-02T00:00:00+00:00'"
+    ).fetchone() == (123, 45)
+    conn.close()
+
+
+def test_upgrade_retains_local_midnight_interval_once_as_shared_evidence(tmp_path):
+    db = tmp_path / "shared.db"
+    conn = _legacy_store(db)
+    conn.execute(
+        "INSERT INTO local_days "
+        "(local_date, tz_name, tz_offset, utc_start, utc_end, bytes_written, "
+        " bytes_read, coverage, sample_count, complete, activity_precision) "
+        "VALUES ('2026-09-01', ?, '+05:30', "
+        "'2026-08-31T18:30:00+00:00', '2026-09-01T18:30:00+00:00', "
+        "500, 600, 1.0, 24, 1, 'legacy')",
+        (TIMEZONE,),
+    )
+    conn.execute(
+        "UPDATE monitoring_periods SET started_at = '2026-08-31T18:00:00+00:00'"
+    )
+    conn.execute(
+        "UPDATE controller_segments SET opened_at = '2026-08-31T18:00:00+00:00'"
+    )
+    conn.execute(
+        "UPDATE samples SET ts = '2026-09-01T18:25:00+00:00', "
+        "bytes_written = 1000, bytes_read = 2000 WHERE id = 1"
+    )
+    conn.execute(
+        "UPDATE samples SET ts = '2026-09-01T18:35:00+00:00', "
+        "bytes_written = 1100, bytes_read = 2050 WHERE id = 2"
+    )
+    conn.commit()
+    conn.close()
+
+    conn = init_store(db)
+    shared = conn.execute(
+        "SELECT COUNT(*), SUM(bytes_written), SUM(bytes_read) "
+        "FROM local_day_unallocated_evidence"
+    ).fetchone()
+    assert shared == (1, 100, 50)
+    for local_date in ("2026-09-01", "2026-09-02"):
+        summary = query_local_day_summary(
+            conn, local_date, TIMEZONE,
+            datetime(2026, 9, 4, tzinfo=timezone.utc),
+        )
+        assert summary["bytes_written"] is None
+        assert summary["shared_bytes_written"] == 100
+        assert summary["shared_bytes_read"] == 50
+        assert summary["activity_state"] == "incomplete"
+    from fenris.repair import repair_derivation
+    assert repair_derivation(conn).ok
+    assert conn.execute(
+        "SELECT COUNT(*), SUM(bytes_written), SUM(bytes_read) "
+        "FROM local_day_unallocated_evidence"
+    ).fetchone() == (1, 100, 50)
+    conn.close()
+
+
+def test_interrupted_upgrade_keeps_legacy_day_retryable(tmp_path):
+    db = tmp_path / "interrupted.db"
+    conn = _legacy_store(db)
+    conn.execute(
+        "CREATE TRIGGER interrupt_local_rebuild "
+        "BEFORE INSERT ON local_day_segment_totals "
+        "BEGIN SELECT RAISE(ABORT, 'simulated interruption'); END"
+    )
+    conn.commit()
+    conn.close()
+
+    with pytest.raises(sqlite3.IntegrityError, match="simulated interruption"):
+        init_store(db)
+
+    conn = sqlite3.connect(db)
+    assert conn.execute("PRAGMA user_version").fetchone() == (SOURCE_SCHEMA_VERSION,)
+    assert conn.execute(
+        "SELECT activity_precision, bytes_written FROM local_days"
+    ).fetchone() == ("legacy", 999_999)
+    conn.execute("DROP TRIGGER interrupt_local_rebuild")
+    conn.commit()
+    conn.close()
+
+    conn = init_store(db)
+    summary = query_local_day_summary(
+        conn, LOCAL_DATE, TIMEZONE,
+        datetime(2026, 9, 4, tzinfo=timezone.utc),
+    )
+    assert summary["bytes_written"] == 10_000
+    assert summary["bytes_read"] == 3_000
+    conn.close()
+
+
+def test_prior_migration_step_commits_before_local_day_repair(tmp_path):
+    db = tmp_path / "migration-steps.db"
+    conn = _legacy_store(db)
+    conn.execute("PRAGMA user_version=4")
+    conn.execute(
+        "CREATE TRIGGER interrupt_local_rebuild BEFORE UPDATE OF bytes_written "
+        "ON local_days BEGIN SELECT RAISE(ABORT, 'simulated interruption'); END"
+    )
+    conn.commit()
+    conn.close()
+
+    with pytest.raises(sqlite3.IntegrityError, match="simulated interruption"):
+        init_store(db)
+
+    conn = sqlite3.connect(db)
+    assert conn.execute("PRAGMA user_version").fetchone() == (5,)
+    assert conn.execute(
+        "SELECT 1 FROM sqlite_master WHERE type='table' "
+        "AND name='local_day_segment_totals'"
+    ).fetchone() is not None
+    assert conn.execute(
+        "SELECT bytes_written FROM local_days WHERE local_date=?",
+        (LOCAL_DATE,),
+    ).fetchone() == (999_999,)
+    conn.close()
+
+
+def test_upgrade_does_not_allocate_unzoned_interval_to_overlapping_timezones(
+    tmp_path,
+):
+    db = tmp_path / "overlapping-timezones.db"
+    conn = _legacy_store(db)
+    conn.execute(
+        "INSERT INTO local_days "
+        "(local_date, tz_name, tz_offset, utc_start, utc_end, bytes_written, "
+        " bytes_read, coverage, sample_count, complete, activity_precision) "
+        "VALUES ('2026-09-02', 'UTC', '+00:00', "
+        "'2026-09-02T00:00:00+00:00', '2026-09-03T00:00:00+00:00', "
+        "999999, 888888, 1.0, 24, 1, 'legacy')"
+    )
+    conn.execute(
+        "UPDATE samples SET ts = '2026-09-02T01:00:00+00:00', local_tz = NULL "
+        "WHERE id = 1"
+    )
+    conn.execute(
+        "UPDATE samples SET ts = '2026-09-02T10:00:00+00:00', local_tz = NULL "
+        "WHERE id = 2"
+    )
+    conn.commit()
+    conn.close()
+
+    conn = init_store(db)
+    for tz_name in (TIMEZONE, "UTC"):
+        summary = query_local_day_summary(
+            conn, LOCAL_DATE, tz_name,
+            datetime(2026, 9, 4, tzinfo=timezone.utc),
+        )
+        assert summary["bytes_written"] is None
+        assert summary["bytes_read"] is None
+        assert summary["activity_precision"] == "unavailable"
+        assert summary["activity_state"] == "unavailable"
+    conn.close()
+
+
+def test_upgrade_rejects_interval_before_recorded_controller_segment(
+    tmp_path,
+):
+    db = tmp_path / "segment-boundary.db"
+    conn = _legacy_store(db)
+    conn.execute(
+        "UPDATE controller_segments "
+        "SET opened_at = '2026-09-01T20:00:00+00:00' WHERE id = 1"
+    )
+    conn.commit()
+    conn.close()
+
+    conn = init_store(db)
+    summary = query_local_day_summary(
+        conn, LOCAL_DATE, TIMEZONE,
+        datetime(2026, 9, 4, tzinfo=timezone.utc),
+    )
+    assert summary["bytes_written"] is None
+    assert summary["bytes_read"] is None
+    assert summary["activity_precision"] == "unavailable"
+    conn.close()
+
+
+def test_sample_at_local_midnight_does_not_hide_coarse_reconstruction(tmp_path):
+    db = tmp_path / "midnight-sample.db"
+    conn = _legacy_store(db)
+    conn.execute(
+        "UPDATE samples SET ts = '2026-09-01T17:00:00+00:00' WHERE id = 1"
+    )
+    conn.execute(
+        "UPDATE samples SET ts = ?, local_tz = ? WHERE id = 2",
+        (UTC_END, TIMEZONE),
+    )
+    conn.commit()
+    conn.close()
+
+    conn = init_store(db)
+    summary = query_local_day_summary(
+        conn, LOCAL_DATE, TIMEZONE,
+        datetime(2026, 9, 4, tzinfo=timezone.utc),
+    )
+    assert summary["bytes_written"] == 123
+    assert summary["bytes_read"] == 45
+    assert summary["activity_precision"] == "coarse"
+    assert summary["activity_state"] == "incomplete"
+    conn.close()

tests/test_live_graph.py

@@ -0,0 +1,425 @@
+"""Tests for live activity graph (issue #91).
+
+Covers:
+- Live interval volume query from raw samples
+- LiveActivityGraph widget rendering, toggle, and inspection
+- Three-minute cadence constants
+- TUI integration with live graph
+"""
+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.activity_selection import IntervalIdentity
+from fenris.monitoring_periods import ensure_period_open
+from fenris.status import ACCURACY_SEC, CADENCE_DEFAULT_S, FRESH_THRESHOLD_S
+from fenris.store import init_store
+from fenris.tui import (
+    LIVE_WINDOW_H,
+    FenrisTuiApp,
+    LiveActivityGraph,
+    _query_live_graph_data,
+)
+
+# ---------------------------------------------------------------------------
+# 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_sample(conn, ts, bw=512000000000, br=256000000000,
+                    segment_id=None, 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, segment_id) "
+        "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)",
+        (ts, device, 1000000, 500000, pu, bw, br, 8765, segment_id),
+    )
+    conn.commit()
+
+
+def _open_period(conn, start="2026-09-01T00:00:00+00:00"):
+    ensure_period_open(conn, datetime.fromisoformat(start))
+
+
+def _live_intervals(count=4):
+    first = datetime(2026, 9, 28, 12, 0, tzinfo=timezone.utc)
+    intervals = []
+    for index in range(count):
+        start = first + timedelta(minutes=3 * index)
+        end = start + timedelta(minutes=3)
+        intervals.append({
+            "start_ts": start.isoformat(),
+            "end_ts": end.isoformat(),
+            "start_label": start.strftime("%H:%M"),
+            "end_label": end.strftime("%H:%M"),
+            "bytes_written": (index + 1) * 1000,
+            "bytes_read": (index + 1) * 500,
+            "elapsed_s": 180,
+            "is_gap": False,
+            "is_zero": False,
+            "is_segment_boundary": False,
+        })
+    return intervals
+
+
+# ---------------------------------------------------------------------------
+# Cadence constants (issue #91 AC1)
+# ---------------------------------------------------------------------------
+
+class TestCadenceConstants:
+    def test_cadence_default_is_3_minutes(self):
+        """Default collection cadence is 3 minutes (180 s)."""
+        assert CADENCE_DEFAULT_S == 180
+
+    def test_fresh_threshold_uses_3min_cadence(self):
+        """Fresh threshold = 2 × 3min + AccuracySec + 60s = 450s."""
+        expected = 2 * 180 + ACCURACY_SEC + 60
+        assert FRESH_THRESHOLD_S == expected
+
+    def test_live_window_is_3_hours(self):
+        """Live graph window is 3 hours."""
+        assert LIVE_WINDOW_H == 3
+
+
+# ---------------------------------------------------------------------------
+# Live graph query (issue #91 AC2-5)
+# ---------------------------------------------------------------------------
+
+class TestQueryLiveData:
+    def test_empty_store_returns_empty(self, tmp_path):
+        """No samples → empty list."""
+        conn = init_store(tmp_path / "test.db")
+        now = _clock()
+        result = _query_live_graph_data(conn, now)
+        assert result == []
+        conn.close()
+
+    def test_single_sample_returns_empty(self, tmp_path):
+        """One sample (no pair) → empty list."""
+        conn = init_store(tmp_path / "test.db")
+        now = _clock()
+        _insert_sample(conn, now.isoformat())
+        result = _query_live_graph_data(conn, now)
+        assert result == []
+        conn.close()
+
+    def test_two_samples_in_window(self, tmp_path):
+        """Two samples within 3h window produce one interval."""
+        conn = init_store(tmp_path / "test.db")
+        now = _clock()
+        t1 = (now - timedelta(minutes=3)).isoformat()
+        t2 = (now - timedelta(minutes=0)).isoformat()
+        _insert_sample(conn, t1, bw=1000, br=500)
+        _insert_sample(conn, t2, bw=1500, br=700)
+        result = _query_live_graph_data(conn, now)
+        assert len(result) == 1
+        assert result[0]["bytes_written"] == 500
+        assert result[0]["bytes_read"] == 200
+        assert result[0]["elapsed_s"] == 180
+        assert result[0]["is_gap"] is False
+        assert result[0]["is_zero"] is False
+        conn.close()
+
+    def test_samples_outside_window_ignored(self, tmp_path):
+        """Samples older than 3h are excluded."""
+        conn = init_store(tmp_path / "test.db")
+        now = _clock()
+        old = (now - timedelta(hours=4)).isoformat()
+        recent = (now - timedelta(minutes=1)).isoformat()
+        _insert_sample(conn, old, bw=1000, br=500)
+        _insert_sample(conn, recent, bw=1500, br=700)
+        result = _query_live_graph_data(conn, now)
+        assert len(result) == 0
+        conn.close()
+
+    def test_gap_detection(self, tmp_path):
+        """Interval > 3× cadence is flagged as a gap."""
+        conn = init_store(tmp_path / "test.db")
+        now = _clock()
+        t1 = (now - timedelta(minutes=13)).isoformat()
+        t2 = (now - timedelta(minutes=3)).isoformat()
+        _insert_sample(conn, t1, bw=1000, br=500)
+        _insert_sample(conn, t2, bw=1500, br=700)
+        result = _query_live_graph_data(conn, now)
+        assert len(result) == 1
+        assert result[0]["is_gap"] is True
+        conn.close()
+
+    def test_zero_interval(self, tmp_path):
+        """No byte delta → is_zero flag."""
+        conn = init_store(tmp_path / "test.db")
+        now = _clock()
+        t1 = (now - timedelta(minutes=3)).isoformat()
+        t2 = (now - timedelta(minutes=0)).isoformat()
+        _insert_sample(conn, t1, bw=1000, br=500)
+        _insert_sample(conn, t2, bw=1000, br=500)
+        result = _query_live_graph_data(conn, now)
+        assert len(result) == 1
+        assert result[0]["bytes_written"] == 0
+        assert result[0]["bytes_read"] == 0
+        assert result[0]["is_zero"] is True
+        conn.close()
+
+    def test_segment_boundary_resets_counters(self, tmp_path):
+        """Counter discontinuity across segments → zero delta."""
+        conn = init_store(tmp_path / "test.db")
+        _insert_segment(conn, identity_key="key_a")
+        _insert_segment(conn, opened_at="2026-09-30T11:00:00+00:00",
+                        identity_key="key_b")
+        now = _clock()
+        t1 = (now - timedelta(minutes=6)).isoformat()
+        t2 = (now - timedelta(minutes=3)).isoformat()
+        _insert_sample(conn, t1, bw=1000, br=500, segment_id=1)
+        _insert_sample(conn, t2, bw=500, br=200, segment_id=2)
+        result = _query_live_graph_data(conn, now)
+        assert len(result) == 1
+        assert result[0]["bytes_written"] == 0
+        assert result[0]["bytes_read"] == 0
+        assert result[0]["is_segment_boundary"] is True
+        conn.close()
+
+    def test_actual_timestamps_used(self, tmp_path):
+        """Points use actual sample timestamps, not 3-min spacing."""
+        conn = init_store(tmp_path / "test.db")
+        now = _clock()
+        t1 = (now - timedelta(minutes=5)).isoformat()
+        t2 = (now - timedelta(minutes=1)).isoformat()
+        _insert_sample(conn, t1, bw=1000, br=500)
+        _insert_sample(conn, t2, bw=2000, br=800)
+        result = _query_live_graph_data(conn, now)
+        assert len(result) == 1
+        assert result[0]["start_ts"] == t1
+        assert result[0]["end_ts"] == t2
+        assert result[0]["elapsed_s"] == 240
+        conn.close()
+
+    def test_multiple_intervals_ordered_oldest_first(self, tmp_path):
+        """Multiple intervals are returned in chronological order."""
+        conn = init_store(tmp_path / "test.db")
+        now = _clock()
+        for i in range(5):
+            ts = (now - timedelta(minutes=15 - i * 3)).isoformat()
+            _insert_sample(conn, ts, bw=1000 * (i + 1), br=500 * (i + 1))
+        result = _query_live_graph_data(conn, now)
+        assert len(result) == 4
+        for i in range(len(result) - 1):
+            assert result[i]["end_ts"] <= result[i + 1]["start_ts"]
+        conn.close()
+
+
+# ---------------------------------------------------------------------------
+# LiveActivityGraph widget (issue #91 AC3)
+# ---------------------------------------------------------------------------
+
+class TestLiveActivityGraph:
+    @pytest.mark.asyncio
+    async def test_toggle_measure(self, tmp_path):
+        """Toggle switches between written and read."""
+        app = FenrisTuiApp(store_path=tmp_path / "test.db")
+        async with app.run_test() as pilot:
+            await pilot.pause()
+            graph = app.query_one("#live-activity")
+            assert graph.measure == "written"
+            graph.toggle_measure()
+            assert graph.measure == "read"
+            graph.toggle_measure()
+            assert graph.measure == "written"
+
+    @pytest.mark.asyncio
+    async def test_empty_data_renders_awaiting(self, tmp_path):
+        """Empty data shows awaiting message."""
+        app = FenrisTuiApp(store_path=tmp_path / "test.db")
+        async with app.run_test() as pilot:
+            await pilot.pause()
+            graph = app.query_one("#live-activity")
+            graph.set_data([])
+            await pilot.pause()
+            render = str(graph.query_one("#live-render").render())
+            assert "Awaiting intervals" in render
+
+    @pytest.mark.asyncio
+    async def test_data_renders_header(self, tmp_path):
+        """Data updates the header with interval count."""
+        app = FenrisTuiApp(store_path=tmp_path / "test.db")
+        async with app.run_test() as pilot:
+            await pilot.pause()
+            graph = app.query_one("#live-activity")
+            data = [
+                {
+                    "start_ts": "2026-09-30T11:57:00+00:00",
+                    "end_ts": "2026-09-30T12:00:00+00:00",
+                    "start_label": "11:57",
+                    "end_label": "12:00",
+                    "bytes_written": 500000000,
+                    "bytes_read": 200000000,
+                    "elapsed_s": 180,
+                    "is_gap": False,
+                    "is_zero": False,
+                    "is_segment_boundary": False,
+                },
+            ]
+            graph.set_data(data)
+            await pilot.pause()
+            header = str(graph.query_one("#live-header").render())
+            assert "1 intervals" in header
+            assert "w W/R" in str(app.query_one("#activity-tools").render())
+
+
+# ---------------------------------------------------------------------------
+# TUI integration (issue #91 AC2, AC6-9)
+# ---------------------------------------------------------------------------
+
+class TestTUILiveIntegration:
+    @pytest.mark.asyncio
+    async def test_live_graph_exists_in_compose(self, tmp_path):
+        """Live activity graph is composed in the TUI."""
+        app = FenrisTuiApp(store_path=tmp_path / "test.db")
+        async with app.run_test() as pilot:
+            await pilot.pause()
+            assert app.query_one("#live-activity") is not None
+            assert isinstance(app.query_one("#live-activity"), LiveActivityGraph)
+
+    @pytest.mark.asyncio
+    async def test_live_graph_has_border_title(self, tmp_path):
+        """Live activity graph has a border title."""
+        app = FenrisTuiApp(store_path=tmp_path / "test.db")
+        async with app.run_test() as pilot:
+            await pilot.pause()
+            live = app.query_one("#live-activity")
+            assert live.border_title == "Live activity"
+
+    @pytest.mark.asyncio
+    async def test_today_action_resets_drill(self, tmp_path):
+        """Action today returns from hourly drill to daily view."""
+        app = FenrisTuiApp(store_path=tmp_path / "test.db")
+        async with app.run_test() as pilot:
+            await pilot.pause()
+            graph = app.query_one("#usage-history")
+            graph.view_mode = "hourly"
+            graph.drill_day = "2026-09-30"
+            app.action_today()
+            await pilot.pause()
+            assert graph.view_mode == "daily"
+
+    @pytest.mark.asyncio
+    async def test_toggle_measure_binding(self, tmp_path):
+        """The w key toggles the live graph measure."""
+        app = FenrisTuiApp(store_path=tmp_path / "test.db")
+        async with app.run_test() as pilot:
+            await pilot.pause()
+            graph = app.query_one("#live-activity")
+            assert graph.measure == "written"
+            await pilot.press("w")
+            await pilot.pause()
+            assert graph.measure == "read"
+
+    @pytest.mark.asyncio
+    async def test_constrained_mode_hides_live_graph(self, tmp_path):
+        """Constrained terminal hides the live graph."""
+        app = FenrisTuiApp(store_path=tmp_path / "test.db")
+        async with app.run_test(size=(70, 20)) as pilot:
+            await pilot.pause()
+            main_grid = app.query_one("#main-grid")
+            assert main_grid.has_class("constrained")
+
+    @pytest.mark.asyncio
+    @pytest.mark.parametrize("size", [(100, 40), (70, 20)])
+    async def test_follow_pin_expiry_and_today_use_visible_readout(self, tmp_path, size):
+        """Live selection follows, pins, expires, and resets at both layout sizes."""
+        app = FenrisTuiApp(store_path=tmp_path / "test.db", refresh_interval_s=999)
+        intervals = _live_intervals()
+        async with app.run_test(size=size) as pilot:
+            await pilot.pause()
+            graph = app.query_one("#live-activity")
+            graph.set_data(intervals[:3])
+
+            readout = str(app.query_one("#live-readout").render())
+            assert "12:09 UTC" in readout
+            assert graph.selection.following_live
+            assert graph.selection.selected_live_interval == IntervalIdentity(
+                intervals[2]["start_ts"], intervals[2]["end_ts"]
+            )
+
+            # Refresh while following selects the newly measured newest point.
+            graph.set_data(intervals)
+            assert "12:12 UTC" in str(app.query_one("#live-readout").render())
+
+            # Live graph receives focus at launch; first arrow pins immediately.
+            await pilot.press("left")
+            pinned = graph.selection.selected_live_interval
+            readout = str(app.query_one("#live-readout").render())
+            assert "12:09 UTC" in readout
+            assert not graph.selection.following_live
+
+            graph.set_data(intervals)
+            readout = str(app.query_one("#live-readout").render())
+            assert "12:09 UTC" in readout
+            assert graph.selection.selected_live_interval == pinned
+
+            # Read/write changes presentation only; pinned point stays stable.
+            await pilot.press("w")
+            graph.set_data(intervals)
+            assert graph.measure == "read"
+            assert graph.selection.selected_live_interval == pinned
+            assert "12:09 UTC" in str(app.query_one("#live-readout").render())
+
+            # Remove pinned interval from rolling window. Explain expiration.
+            graph.set_data(intervals[3:])
+            readout = str(app.query_one("#live-readout").render())
+            assert "Inspected interval expired; following live" in readout
+            assert "12:12 UTC" in readout
+            assert graph.selection.following_live
+
+            # Today action clears expiration and resumes newest-point following.
+            await pilot.press("t")
+            assert graph.selection.following_live
+            assert not graph.selection.live_interval_expired
+            graph.set_data(intervals)
+            readout = str(app.query_one("#live-readout").render())
+            assert "12:12 UTC" in readout
+            assert "Inspected interval expired" not in readout
+            assert graph.selection.following_live
+
+    @pytest.mark.asyncio
+    async def test_mouse_inspection_pins_same_interval_identity(self, tmp_path):
+        """Mouse inspection pins the interval at its visible graph location."""
+        app = FenrisTuiApp(store_path=tmp_path / "test.db", refresh_interval_s=999)
+        intervals = _live_intervals()
+        async with app.run_test(size=(100, 40)) as pilot:
+            await pilot.pause()
+            graph = app.query_one("#live-activity")
+            graph.set_data(intervals[:3])
+            await pilot.pause()
+            render = app.query_one("#live-render")
+            await pilot.click(
+                "#live-render",
+                offset=(8, max(0, render.content_size.height // 2)),
+            )
+            await pilot.pause()
+
+            expected = IntervalIdentity(
+                intervals[0]["start_ts"], intervals[0]["end_ts"]
+            )
+            assert graph.selection.selected_live_interval == expected
+            assert not graph.selection.following_live
+            assert "12:03 UTC" in str(app.query_one("#live-readout").render())

tests/test_local_day.py

@@ -0,0 +1,924 @@
+"""Local-day activity derivation tests (issue #90, ADR 0010).
+
+Verifies that local-day summaries are correctly derived from UTC hour
+observations, that the schema migration creates the local_days table,
+that timezone boundaries are preserved across system-timezone changes,
+and that midnight-spanning intervals are retained as shared evidence
+without double counting.
+
+Seams:
+- write side: collector.run_collection() → local_day derivation
+- read side: local_day.query_current_local_day(), query_local_day_summary()
+- persistence: store.init_store() → local_days table, migration 2→3
+"""
+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.store import init_store, SCHEMA_VERSION
+from fenris.local_day import (
+    derive_local_day_summary,
+    persist_local_day,
+    record_local_activity_interval,
+    query_local_day_summary,
+    query_current_local_day,
+    LocalDaySummary,
+)
+from fenris.monitoring_periods import ensure_period_open, close_period
+
+
+# ---------------------------------------------------------------------------
+# Fixtures
+# ---------------------------------------------------------------------------
+
+def _make_smartctl(duw: int, dur: 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,
+            "data_units_read": dur, "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_tree(tmp_path: Path) -> Path:
+    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
+
+
+class _Clock:
+    def __init__(self, initial: datetime):
+        self.now = initial
+    def utcnow(self):
+        return self.now
+
+
+def _insert_hour(conn, hour_iso, bw=0, br=0, sample_count=1,
+                 active=3600, idle=0, powered_off=0, unknown=0):
+    """Insert a UTC hour observation."""
+    known = active + idle + powered_off
+    coverage = known / 3600.0
+    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, active, idle, powered_off, unknown, bw, br, sample_count, coverage),
+    )
+    conn.commit()
+
+
+# ---------------------------------------------------------------------------
+# Schema migration: local_days table is created
+# ---------------------------------------------------------------------------
+
+class TestSchemaMigration:
+    """Store version 3 includes the local_days table."""
+
+    def test_fresh_store_has_local_days(self, tmp_path):
+        conn = init_store(tmp_path / "obs.db")
+        tables = {row[0] for row in conn.execute(
+            "SELECT name FROM sqlite_master WHERE type='table'"
+        ).fetchall()}
+        assert "local_days" in tables
+        conn.close()
+
+    def test_migration_from_v2_creates_local_days(self, tmp_path):
+        db = tmp_path / "obs.db"
+        conn = sqlite3.connect(str(db))
+        conn.execute("PRAGMA user_version=2")
+        conn.commit()
+        conn.close()
+
+        conn = init_store(db)
+        tables = {row[0] for row in conn.execute(
+            "SELECT name FROM sqlite_master WHERE type='table'"
+        ).fetchall()}
+        assert "local_days" in tables
+        assert conn.execute("PRAGMA user_version").fetchone()[0] == SCHEMA_VERSION
+        conn.close()
+
+    def test_migration_is_idempotent(self, tmp_path):
+        db = tmp_path / "obs.db"
+        conn = init_store(db)
+        conn.close()
+        # Reopening should not fail
+        conn = init_store(db)
+        count = conn.execute("SELECT COUNT(*) FROM local_days").fetchone()[0]
+        assert count == 0
+        conn.close()
+
+    def test_v4_totals_keep_values_but_are_not_treated_as_local_precision(
+        self, tmp_path,
+    ):
+        db = tmp_path / "v4.db"
+        conn = sqlite3.connect(db)
+        conn.execute(
+            "CREATE TABLE samples (id INTEGER PRIMARY KEY, ts TEXT, device TEXT)"
+        )
+        conn.execute(
+            "CREATE TABLE pending_publications "
+            "(id INTEGER PRIMARY KEY, sample_ts TEXT, payload TEXT)"
+        )
+        conn.execute(
+            "CREATE TABLE local_days ("
+            "id INTEGER PRIMARY KEY, local_date TEXT NOT NULL, tz_name TEXT NOT NULL, "
+            "tz_offset TEXT NOT NULL, utc_start TEXT NOT NULL, utc_end TEXT NOT NULL, "
+            "bytes_written INTEGER DEFAULT 0, bytes_read INTEGER DEFAULT 0, "
+            "coverage REAL DEFAULT 0, sample_count INTEGER DEFAULT 0, "
+            "complete BOOLEAN DEFAULT 0, UNIQUE(local_date, tz_name))"
+        )
+        conn.execute(
+            "INSERT INTO local_days VALUES "
+            "(1, '2026-09-01', 'UTC', '+00:00', "
+            "'2026-09-01T00:00:00+00:00', '2026-09-02T00:00:00+00:00', "
+            "5120000, 2048000, 0.5, 10, 0)"
+        )
+        conn.execute("PRAGMA user_version=4")
+        conn.commit()
+        conn.close()
+
+        conn = init_store(db)
+        stored = conn.execute(
+            "SELECT bytes_written, activity_precision FROM local_days"
+        ).fetchone()
+        assert stored == (5_120_000, "unavailable")
+        visible = query_local_day_summary(conn, "2026-09-01", "UTC")
+        assert visible["bytes_written"] is None
+        assert visible["activity_state"] == "unavailable"
+        assert "local_tz" in {
+            row[1] for row in conn.execute("PRAGMA table_info(samples)")
+        }
+        conn.close()
+
+
+# ---------------------------------------------------------------------------
+# Local-day coverage derivation from UTC hours
+# ---------------------------------------------------------------------------
+
+class TestDeriveLocalDay:
+    """Derive coverage from UTC hours without allocating local-day bytes."""
+
+    def test_utc_plus_zero(self, tmp_path):
+        """UTC timezone: local day boundaries = UTC day boundaries."""
+        conn = init_store(tmp_path / "obs.db")
+        ensure_period_open(conn, datetime(2026, 9, 1, 0, 0, 0, tzinfo=timezone.utc))
+
+        _insert_hour(conn, "2026-09-01T10:00:00+00:00", bw=100, br=50)
+        _insert_hour(conn, "2026-09-01T11:00:00+00:00", bw=200, br=80)
+
+        clock = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        summary = derive_local_day_summary(conn, "UTC", clock)
+
+        assert summary is not None
+        assert summary.local_date == "2026-09-01"
+        assert summary.tz_name == "UTC"
+        assert summary.tz_offset == "+00:00"
+        assert summary.bytes_written == 0
+        assert summary.bytes_read == 0
+        assert summary.activity_precision == "unavailable"
+        assert summary.complete is False  # not all 24 hours covered
+        conn.close()
+
+    def test_utc_plus_five_thirty(self, tmp_path):
+        """Asia/Kolkata half-hour offset: UTC boundaries are offset."""
+        conn = init_store(tmp_path / "obs.db")
+
+        # Local day 2026-09-01 in +05:30 is UTC [2026-08-31T18:30, 2026-09-01T18:30)
+        # Insert UTC hours that belong to this local day
+        _insert_hour(conn, "2026-08-31T19:00:00+00:00", bw=100, br=50)
+        _insert_hour(conn, "2026-09-01T10:00:00+00:00", bw=200, br=80)
+
+        clock = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)  # 17:30 local
+        summary = derive_local_day_summary(conn, "Asia/Kolkata", clock)
+
+        assert summary is not None
+        assert summary.local_date == "2026-09-01"
+        assert summary.tz_name == "Asia/Kolkata"
+        assert summary.tz_offset == "+05:30"
+        assert summary.bytes_written == 0
+        assert summary.bytes_read == 0
+        assert summary.activity_precision == "unavailable"
+        conn.close()
+
+    def test_hourly_bytes_cannot_be_allocated_to_local_midnight(self, tmp_path):
+        """UTC-hour totals do not establish exact local-day byte totals."""
+        conn = init_store(tmp_path / "obs.db")
+
+        # For UTC+5:30, local day 2026-09-01 starts at 2026-08-31T18:30 UTC
+        # UTC hour 2026-08-31T18:00 covers 18:00-19:00, straddling the midnight
+        _insert_hour(conn, "2026-08-31T18:00:00+00:00", bw=100, br=50)
+        _insert_hour(conn, "2026-08-31T19:00:00+00:00", bw=200, br=80)
+
+        clock = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        summary = derive_local_day_summary(conn, "Asia/Kolkata", clock)
+
+        assert summary is not None
+        assert summary.bytes_written == 0
+        assert summary.bytes_read == 0
+        assert summary.activity_precision == "unavailable"
+        conn.close()
+
+    def test_no_hours_returns_none(self, tmp_path):
+        conn = init_store(tmp_path / "obs.db")
+        clock = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        summary = derive_local_day_summary(conn, "UTC", clock)
+        assert summary is None
+        conn.close()
+
+
+# ---------------------------------------------------------------------------
+# Persistence and querying
+# ---------------------------------------------------------------------------
+
+class TestLocalDayPersistence:
+    """Local-day summaries persist and can be queried."""
+
+    def test_persist_and_query(self, tmp_path):
+        conn = init_store(tmp_path / "obs.db")
+        summary = LocalDaySummary(
+            local_date="2026-09-01", tz_name="UTC", tz_offset="+00:00",
+            utc_start="2026-09-01T00:00:00+00:00",
+            utc_end="2026-09-02T00:00:00+00:00",
+            bytes_written=300, bytes_read=130,
+            coverage=0.5, sample_count=4, complete=False,
+        )
+        created = persist_local_day(conn, summary)
+        assert created is True
+
+        # Upsert again — should update, not create
+        created2 = persist_local_day(conn, summary)
+        assert created2 is False
+
+        result = query_local_day_summary(conn, "2026-09-01")
+        assert result is not None
+        assert result["bytes_written"] == 300
+        assert result["tz_name"] == "UTC"
+        conn.close()
+
+    def test_query_nonexistent_returns_none(self, tmp_path):
+        conn = init_store(tmp_path / "obs.db")
+        assert query_local_day_summary(conn, "2026-01-01") is None
+        conn.close()
+
+    def test_query_current_local_day(self, tmp_path):
+        conn = init_store(tmp_path / "obs.db")
+        summary = LocalDaySummary(
+            local_date="2026-09-01", tz_name="UTC", tz_offset="+00:00",
+            utc_start="2026-09-01T00:00:00+00:00",
+            utc_end="2026-09-02T00:00:00+00:00",
+            bytes_written=500, bytes_read=200,
+            coverage=0.8, sample_count=10, complete=True,
+        )
+        persist_local_day(conn, summary)
+
+        clock = datetime(2026, 9, 1, 15, 0, 0, tzinfo=timezone.utc)
+        result = query_current_local_day(conn, clock, "UTC")
+        assert result is not None
+        assert result["bytes_written"] == 500
+        conn.close()
+
+
+# ---------------------------------------------------------------------------
+# Timezone change handling
+# ---------------------------------------------------------------------------
+
+class TestTimezoneChange:
+    """Historical summaries retain their recorded timezone."""
+
+    def test_old_tz_preserved_after_change(self, tmp_path):
+        conn = init_store(tmp_path / "obs.db")
+
+        # Old summary in UTC
+        old = LocalDaySummary(
+            local_date="2026-09-01", tz_name="UTC", tz_offset="+00:00",
+            utc_start="2026-09-01T00:00:00+00:00",
+            utc_end="2026-09-02T00:00:00+00:00",
+            bytes_written=100, bytes_read=50,
+            coverage=0.5, sample_count=5, complete=False,
+        )
+        persist_local_day(conn, old)
+
+        # System timezone changes to Asia/Kolkata
+        # Old summary retains UTC
+        result = query_local_day_summary(conn, "2026-09-01")
+        assert result is not None
+        assert result["tz_name"] == "UTC"
+        assert result["tz_offset"] == "+00:00"
+        conn.close()
+
+    def test_different_tz_same_date_stored_separately(self, tmp_path):
+        conn = init_store(tmp_path / "obs.db")
+
+        # Two summaries for same date in different timezones
+        for tz, offset in [("UTC", "+00:00"), ("Asia/Kolkata", "+05:30")]:
+            summary = LocalDaySummary(
+                local_date="2026-09-01", tz_name=tz, tz_offset=offset,
+                utc_start="2026-09-01T00:00:00+00:00",
+                utc_end="2026-09-02T00:00:00+00:00",
+                bytes_written=100, bytes_read=50,
+                coverage=0.5, sample_count=5, complete=False,
+            )
+            persist_local_day(conn, summary)
+
+        # Both exist independently — query by specific timezone
+        utc_row = conn.execute(
+            "SELECT tz_name, bytes_written FROM local_days "
+            "WHERE local_date = '2026-09-01' AND tz_name = 'UTC'"
+        ).fetchone()
+        assert utc_row is not None
+        assert utc_row[0] == "UTC"
+        assert utc_row[1] == 100
+
+        in_row = conn.execute(
+            "SELECT tz_name, bytes_written FROM local_days "
+            "WHERE local_date = '2026-09-01' AND tz_name = 'Asia/Kolkata'"
+        ).fetchone()
+        assert in_row is not None
+        assert in_row[0] == "Asia/Kolkata"
+        conn.close()
+
+
+# ---------------------------------------------------------------------------
+# Coverage and completeness
+# ---------------------------------------------------------------------------
+
+class TestLocalDayCompleteness:
+    """Complete days vs partial current day."""
+
+    def test_incomplete_when_missing_hours(self, tmp_path):
+        conn = init_store(tmp_path / "obs.db")
+        _insert_hour(conn, "2026-09-01T12:00:00+00:00", bw=100, br=50)
+
+        clock = datetime(2026, 9, 1, 13, 0, 0, tzinfo=timezone.utc)
+        summary = derive_local_day_summary(conn, "UTC", clock)
+
+        assert summary is not None
+        assert summary.complete is False
+        assert summary.coverage < 1.0
+        conn.close()
+
+    def test_coverage_ratio(self, tmp_path):
+        conn = init_store(tmp_path / "obs.db")
+        # 2 hours of known data out of 24 total UTC hours in a UTC day
+        _insert_hour(conn, "2026-09-01T10:00:00+00:00", bw=100, active=3600)
+        _insert_hour(conn, "2026-09-01T11:00:00+00:00", bw=200, active=3600)
+
+        clock = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        summary = derive_local_day_summary(conn, "UTC", clock)
+
+        assert summary is not None
+        # 7200 known seconds / 86400 total = ~0.083
+        assert summary.coverage == pytest.approx(7200 / 86400, rel=0.01)
+        conn.close()
+
+
+# ---------------------------------------------------------------------------
+# Collector integration
+# ---------------------------------------------------------------------------
+
+class TestCollectorIntegration:
+    """Collector derives local-day summaries during collection."""
+
+    def test_collection_creates_local_day(self, tmp_path, sysfs_tree):
+        from fenris.collector import run_collection
+
+        t1 = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        t2 = datetime(2026, 9, 1, 12, 5, 0, tzinfo=timezone.utc)
+        store = str(tmp_path / "obs.db")
+        cfg = {"device": "/dev/nvme0", "store_path": store}
+        sysfs_nvme = sysfs_tree / "sys" / "class" / "nvme" / "nvme0"
+
+        run_collection(_make_smartctl(10000000, 8000000), sysfs_nvme, cfg, _Clock(t1))
+        run_collection(_make_smartctl(10000050, 8000030), sysfs_nvme, cfg, _Clock(t2))
+
+        conn = sqlite3.connect(store)
+        count = conn.execute("SELECT COUNT(*) FROM local_days").fetchone()[0]
+        assert count >= 1
+
+        # Verify the local day has the expected write/read data
+        row = conn.execute(
+            "SELECT bytes_written, bytes_read, complete FROM local_days LIMIT 1"
+        ).fetchone()
+        assert row is not None
+        assert row[0] == 50 * 512000  # writes
+        assert row[1] == 30 * 512000  # reads
+        conn.close()
+
+    def test_interval_crossing_utc_hour_stays_wholly_in_local_day(
+        self, tmp_path, sysfs_tree, monkeypatch,
+    ):
+        """A measured interval inside one local date keeps its full delta."""
+        from fenris.collector import run_collection
+
+        monkeypatch.setenv("TZ", "Asia/Kolkata")
+        store = str(tmp_path / "obs.db")
+        cfg = {"device": "/dev/nvme0", "store_path": store}
+        sysfs_nvme = sysfs_tree / "sys" / "class" / "nvme" / "nvme0"
+        first_at = datetime(2026, 9, 1, 12, 59, tzinfo=timezone.utc)
+        second_at = datetime(2026, 9, 1, 13, 1, tzinfo=timezone.utc)
+
+        first = run_collection(
+            _make_smartctl(10_000_000, 8_000_000),
+            sysfs_nvme,
+            cfg,
+            _Clock(first_at),
+        )
+        second = run_collection(
+            _make_smartctl(10_000_010, 8_000_004),
+            sysfs_nvme,
+            cfg,
+            _Clock(second_at),
+        )
+
+        assert first["ok"] and second["ok"]
+        conn = sqlite3.connect(store)
+        summary = query_local_day_summary(conn, "2026-09-01")
+
+        assert summary is not None
+        assert summary["bytes_written"] == 5_120_000
+        assert summary["bytes_read"] == 2_048_000
+        assert summary["segments"] == [{
+            "segment_id": 1,
+            "bytes_written": 5_120_000,
+            "bytes_read": 2_048_000,
+            "activity_seconds": 120,
+            "activity_intervals": 1,
+        }]
+        segment_totals = conn.execute(
+            "SELECT segment_id, bytes_written, bytes_read, activity_intervals "
+            "FROM local_day_segment_totals"
+        ).fetchone()
+        assert segment_totals == (1, 5_120_000, 2_048_000, 1)
+
+        samples = conn.execute(
+            "SELECT id, ts, bytes_written, bytes_read, local_tz "
+            "FROM samples ORDER BY id"
+        ).fetchall()
+        first_sample, second_sample = samples
+        assert record_local_activity_interval(
+            conn,
+            dict(zip(("id", "ts", "bytes_written", "bytes_read", "local_tz"), first_sample)),
+            dict(zip(("id", "ts", "bytes_written", "bytes_read", "local_tz"), second_sample)),
+            start_sample_id=first_sample[0],
+            end_sample_id=second_sample[0],
+            segment_id=1,
+        ) == "known"
+        repeated = query_local_day_summary(conn, "2026-09-01", "Asia/Kolkata")
+        assert repeated["bytes_written"] == 5_120_000
+        assert repeated["bytes_read"] == 2_048_000
+        assert conn.execute(
+            "SELECT SUM(bytes_written), SUM(bytes_read), SUM(activity_intervals) "
+            "FROM local_day_segment_totals"
+        ).fetchone() == (5_120_000, 2_048_000, 1)
+        conn.close()
+
+    @pytest.mark.parametrize(
+        (
+            "first_at", "second_at", "local_date", "expected_hours",
+            "expected_start", "expected_end", "expected_offset",
+        ),
+        [
+            (
+                datetime(2026, 3, 8, 6, 30, tzinfo=timezone.utc),
+                datetime(2026, 3, 8, 7, 30, tzinfo=timezone.utc),
+                "2026-03-08", 23,
+                "2026-03-08T05:00:00+00:00",
+                "2026-03-09T04:00:00+00:00", "-05:00",
+            ),
+            (
+                datetime(2026, 11, 1, 5, 30, tzinfo=timezone.utc),
+                datetime(2026, 11, 1, 6, 30, tzinfo=timezone.utc),
+                "2026-11-01", 25,
+                "2026-11-01T04:00:00+00:00",
+                "2026-11-02T05:00:00+00:00", "-04:00",
+            ),
+        ],
+        ids=("spring-forward", "fall-back-repeated-hour"),
+    )
+    def test_collector_retains_exact_interval_on_dst_local_day(
+        self,
+        tmp_path,
+        sysfs_tree,
+        monkeypatch,
+        first_at,
+        second_at,
+        local_date,
+        expected_hours,
+        expected_start,
+        expected_end,
+        expected_offset,
+    ):
+        """Collection preserves exact activity on short and long local days."""
+        from fenris.collector import run_collection
+
+        zone = "America/New_York"
+        monkeypatch.setenv("TZ", zone)
+        store = str(tmp_path / "obs.db")
+        cfg = {"device": "/dev/nvme0", "store_path": store}
+        sysfs_nvme = sysfs_tree / "sys" / "class" / "nvme" / "nvme0"
+        assert run_collection(
+            _make_smartctl(10_000_000, 8_000_000),
+            sysfs_nvme,
+            cfg,
+            _Clock(first_at),
+        )["ok"]
+        assert run_collection(
+            _make_smartctl(10_000_001, 8_000_002),
+            sysfs_nvme,
+            cfg,
+            _Clock(second_at),
+        )["ok"]
+
+        conn = sqlite3.connect(store)
+        summary = query_local_day_summary(
+            conn, local_date, zone, second_at + timedelta(minutes=1)
+        )
+        assert summary is not None
+        assert summary["bytes_written"] == 512_000
+        assert summary["bytes_read"] == 1_024_000
+        assert summary["activity_seconds"] == 3_600
+        assert summary["utc_start"] == expected_start
+        assert summary["utc_end"] == expected_end
+        assert summary["tz_offset"] == expected_offset
+        assert (
+            datetime.fromisoformat(summary["utc_end"])
+            - datetime.fromisoformat(summary["utc_start"])
+        ).total_seconds() == expected_hours * 3_600
+        conn.close()
+
+    @pytest.mark.asyncio
+    async def test_local_midnight_interval_is_shared_once(
+        self, tmp_path, sysfs_tree, monkeypatch,
+    ):
+        """A real counter interval crossing local midnight stays unallocated."""
+        from fenris.collector import run_collection
+
+        monkeypatch.setenv("TZ", "Asia/Kolkata")
+        store = str(tmp_path / "obs.db")
+        cfg = {"device": "/dev/nvme0", "store_path": store}
+        sysfs_nvme = sysfs_tree / "sys" / "class" / "nvme" / "nvme0"
+        first_at = datetime(2026, 9, 1, 18, 25, tzinfo=timezone.utc)
+        second_at = datetime(2026, 9, 1, 18, 35, tzinfo=timezone.utc)
+
+        first = run_collection(
+            _make_smartctl(10_000_000, 8_000_000),
+            sysfs_nvme,
+            cfg,
+            _Clock(first_at),
+        )
+        second = run_collection(
+            _make_smartctl(10_000_100, 8_000_060),
+            sysfs_nvme,
+            cfg,
+            _Clock(second_at),
+        )
+        assert first["ok"] and second["ok"]
+
+        conn = sqlite3.connect(store)
+        evidence = conn.execute(
+            "SELECT COUNT(*), SUM(bytes_written), SUM(bytes_read) "
+            "FROM local_day_unallocated_evidence"
+        ).fetchone()
+        assert evidence == (1, 51_200_000, 30_720_000)
+        assert conn.execute(
+            "SELECT SUM(bytes_written), SUM(bytes_read) FROM local_days"
+        ).fetchone() == (0, 0)
+
+        for local_date in ("2026-09-01", "2026-09-02"):
+            summary = query_local_day_summary(
+                conn, local_date, "Asia/Kolkata", second_at
+            )
+            assert summary is not None
+            assert summary["bytes_written"] is None
+            assert summary["shared_bytes_written"] == 51_200_000
+            assert summary["shared_bytes_read"] == 30_720_000
+            assert summary["activity_state"] in ("incomplete", "so_far")
+        conn.close()
+
+        from fenris.status import read_status
+        from fenris.tui import FenrisTuiApp
+
+        app = FenrisTuiApp(store_path=Path(store), refresh_interval_s=999)
+        async with app.run_test(size=(100, 32)):
+            app._browse_date = "2026-09-02"
+            with read_status(
+                Path(store), second_at, query_services=False
+            ) as (reader, _):
+                assert reader is not None
+                app._render_local_day(reader)
+            visible = str(app.query_one("#local-day").render())
+            assert "2026-09-02" in visible
+            assert "Asia/Kolkata +05:30" in visible
+            assert "W unavailable" in visible
+            assert "shared at midnight W 0.051 GB" in visible
+
+    def test_synthetic_shared_bytes_conserve_one_hundred_bytes(self, tmp_path):
+        """Shared evidence conserves byte values before display rounding."""
+        conn = init_store(tmp_path / "obs.db")
+        first_at = datetime(2026, 9, 1, 18, 25, tzinfo=timezone.utc)
+        second_at = datetime(2026, 9, 3, 18, 35, tzinfo=timezone.utc)
+        ensure_period_open(conn, first_at)
+        conn.execute(
+            "INSERT INTO samples (ts, device, bytes_written, bytes_read, local_tz) "
+            "VALUES (?, ?, ?, ?, ?)",
+            (first_at.isoformat(), "/dev/nvme0", 1_000, 2_000, "Asia/Kolkata"),
+        )
+        first_id = conn.execute("SELECT last_insert_rowid()").fetchone()[0]
+        conn.execute(
+            "INSERT INTO samples (ts, device, bytes_written, bytes_read, local_tz) "
+            "VALUES (?, ?, ?, ?, ?)",
+            (second_at.isoformat(), "/dev/nvme0", 1_100, 2_050, "Asia/Kolkata"),
+        )
+        second_id = conn.execute("SELECT last_insert_rowid()").fetchone()[0]
+
+        result = record_local_activity_interval(
+            conn,
+            {
+                "id": first_id,
+                "ts": first_at.isoformat(),
+                "bytes_written": 1_000,
+                "bytes_read": 2_000,
+                "local_tz": "Asia/Kolkata",
+            },
+            {
+                "id": second_id,
+                "ts": second_at.isoformat(),
+                "bytes_written": 1_100,
+                "bytes_read": 2_050,
+                "local_tz": "Asia/Kolkata",
+            },
+            start_sample_id=first_id,
+            end_sample_id=second_id,
+            segment_id=1,
+        )
+
+        assert result == "local_midnight"
+        stored = conn.execute(
+            "SELECT COUNT(*), SUM(bytes_written), SUM(bytes_read) "
+            "FROM local_day_unallocated_evidence"
+        ).fetchone()
+        assert stored == (1, 100, 50)
+        record_local_activity_interval(
+            conn,
+            {
+                "id": first_id,
+                "ts": first_at.isoformat(),
+                "bytes_written": 1_000,
+                "bytes_read": 2_000,
+                "local_tz": "Asia/Kolkata",
+            },
+            {
+                "id": second_id,
+                "ts": second_at.isoformat(),
+                "bytes_written": 1_100,
+                "bytes_read": 2_050,
+                "local_tz": "Asia/Kolkata",
+            },
+            start_sample_id=first_id,
+            end_sample_id=second_id,
+            segment_id=1,
+        )
+        assert conn.execute(
+            "SELECT COUNT(*), SUM(bytes_written), SUM(bytes_read) "
+            "FROM local_day_unallocated_evidence"
+        ).fetchone() == (1, 100, 50)
+        assert conn.execute(
+            "SELECT SUM(bytes_written), SUM(bytes_read) FROM local_days"
+        ).fetchone() == (0, 0)
+        middle_day = query_local_day_summary(
+            conn, "2026-09-03", "Asia/Kolkata", second_at + timedelta(days=1)
+        )
+        assert middle_day["shared_bytes_written"] == 100
+        assert middle_day["shared_bytes_read"] == 50
+        assert middle_day["shared_evidence_count"] == 1
+        conn.close()
+
+    def test_timezone_change_keeps_interval_unallocated(
+        self, tmp_path, sysfs_tree, monkeypatch,
+    ):
+        from fenris.collector import run_collection
+
+        store = str(tmp_path / "obs.db")
+        cfg = {"device": "/dev/nvme0", "store_path": store}
+        sysfs_nvme = sysfs_tree / "sys" / "class" / "nvme" / "nvme0"
+        first_at = datetime(2026, 9, 1, 22, 0, tzinfo=timezone.utc)
+        second_at = datetime(2026, 9, 1, 22, 5, tzinfo=timezone.utc)
+
+        monkeypatch.setenv("TZ", "UTC")
+        assert run_collection(
+            _make_smartctl(10_000_000, 8_000_000),
+            sysfs_nvme,
+            cfg,
+            _Clock(first_at),
+        )["ok"]
+        monkeypatch.setenv("TZ", "Asia/Kolkata")
+        assert run_collection(
+            _make_smartctl(10_000_010, 8_000_004),
+            sysfs_nvme,
+            cfg,
+            _Clock(second_at),
+        )["ok"]
+
+        conn = sqlite3.connect(store)
+        event = conn.execute(
+            "SELECT COUNT(*), SUM(bytes_written), MIN(reason) "
+            "FROM local_day_unallocated_evidence"
+        ).fetchone()
+        assert event == (1, 5_120_000, "timezone_change")
+        old_zone = query_local_day_summary(conn, "2026-09-01", "UTC")
+        new_zone = query_local_day_summary(conn, "2026-09-02", "Asia/Kolkata")
+        assert old_zone["bytes_written"] is None
+        assert new_zone["bytes_written"] is None
+        assert old_zone["unallocated_bytes_written"] == 5_120_000
+        assert new_zone["unallocated_bytes_written"] == 5_120_000
+        conn.close()
+
+    def test_pause_boundary_keeps_interval_unallocated(
+        self, tmp_path, sysfs_tree, monkeypatch,
+    ):
+        from fenris.collector import run_collection
+
+        monkeypatch.setenv("TZ", "UTC")
+        store = str(tmp_path / "obs.db")
+        cfg = {"device": "/dev/nvme0", "store_path": store}
+        sysfs_nvme = sysfs_tree / "sys" / "class" / "nvme" / "nvme0"
+        first_at = datetime(2026, 9, 1, 12, 0, tzinfo=timezone.utc)
+        second_at = datetime(2026, 9, 1, 12, 10, tzinfo=timezone.utc)
+        assert run_collection(
+            _make_smartctl(10_000_000, 8_000_000),
+            sysfs_nvme,
+            cfg,
+            _Clock(first_at),
+        )["ok"]
+
+        conn = sqlite3.connect(store)
+        close_period(conn, first_at + timedelta(minutes=5), "user_disabled")
+        conn.close()
+
+        assert run_collection(
+            _make_smartctl(10_000_010, 8_000_004),
+            sysfs_nvme,
+            cfg,
+            _Clock(second_at),
+        )["ok"]
+
+        conn = sqlite3.connect(store)
+        reason = conn.execute(
+            "SELECT reason FROM local_day_unallocated_evidence"
+        ).fetchone()
+        summary = query_local_day_summary(conn, "2026-09-01", "UTC")
+        assert reason == ("monitoring_period",)
+        assert summary["bytes_written"] is None
+        assert summary["unallocated_bytes_written"] == 5_120_000
+        assert summary["shared_bytes_written"] == 0
+        conn.close()
+
+    def test_controller_segment_boundary_marks_local_activity_incomplete(
+        self, tmp_path, sysfs_tree, monkeypatch,
+    ):
+        from fenris.collector import run_collection
+
+        monkeypatch.setenv("TZ", "UTC")
+        store = str(tmp_path / "obs.db")
+        cfg = {"device": "/dev/nvme0", "store_path": store}
+        sysfs_nvme = sysfs_tree / "sys" / "class" / "nvme" / "nvme0"
+        first_at = datetime(2026, 9, 1, 12, 0, tzinfo=timezone.utc)
+        second_at = datetime(2026, 9, 1, 12, 5, tzinfo=timezone.utc)
+        assert run_collection(
+            _make_smartctl(10_000_000, 8_000_000),
+            sysfs_nvme,
+            cfg,
+            _Clock(first_at),
+        )["ok"]
+        assert run_collection(
+            _make_smartctl(10, 8_000_004),
+            sysfs_nvme,
+            cfg,
+            _Clock(second_at),
+        )["ok"]
+
+        conn = sqlite3.connect(store)
+        summary = query_local_day_summary(
+            conn, "2026-09-01", "UTC", second_at
+        )
+        assert summary is not None
+        assert summary["bytes_written"] is None
+        assert summary["activity_state"] == "incomplete"
+        assert conn.execute(
+            "SELECT COUNT(*) FROM local_day_unallocated_evidence"
+        ).fetchone()[0] == 0
+        conn.close()
+
+
+# ---------------------------------------------------------------------------
+# DST handling (23/25-hour days)
+# ---------------------------------------------------------------------------
+
+class TestDSTHandling:
+    """Local days with non-24-hour durations from DST transitions."""
+
+    def test_short_day_23_hours(self, tmp_path):
+        """Spring forward: local day is 23 hours."""
+        conn = init_store(tmp_path / "obs.db")
+
+        # Simulate a 23-hour day in a timezone with DST
+        # For simplicity, just verify the summary records the correct UTC range
+        clock = datetime(2026, 3, 8, 12, 0, 0, tzinfo=timezone.utc)
+        # New York springs forward on 2026-03-08
+        # Local day 2026-03-08 is 23 hours: UTC [07:00, 06:00+1d)
+        _insert_hour(conn, "2026-03-08T08:00:00+00:00", bw=100, active=3600)
+        _insert_hour(conn, "2026-03-08T12:00:00+00:00", bw=200, active=3600)
+
+        summary = derive_local_day_summary(conn, "America/New_York", clock)
+        assert summary is not None
+        assert summary.local_date == "2026-03-08"
+        # UTC range should be approximately 23 hours
+        utc_start = datetime.fromisoformat(summary.utc_start)
+        utc_end = datetime.fromisoformat(summary.utc_end)
+        duration = (utc_end - utc_start).total_seconds()
+        assert duration == 23 * 3600
+        conn.close()
+
+    def test_long_day_25_hours(self):
+        from fenris.local_day import local_day_boundaries
+
+        start, end, offset = local_day_boundaries(
+            "2026-11-01", "America/New_York"
+        )
+        assert (end - start).total_seconds() == 25 * 3600
+        assert offset == "-04:00"
+
+    def test_half_hour_offset_records_exact_local_boundaries(self):
+        from fenris.local_day import local_day_boundaries
+
+        start, end, offset = local_day_boundaries(
+            "2026-09-01", "Asia/Kolkata"
+        )
+        assert start.isoformat() == "2026-08-31T18:30:00+00:00"
+        assert end.isoformat() == "2026-09-01T18:30:00+00:00"
+        assert offset == "+05:30"
+
+    def test_repeated_local_clock_labels_remain_one_recorded_day(
+        self, tmp_path, sysfs_tree, monkeypatch,
+    ):
+        from fenris.collector import run_collection
+
+        monkeypatch.setenv("TZ", "America/New_York")
+        store = str(tmp_path / "obs.db")
+        cfg = {"device": "/dev/nvme0", "store_path": store}
+        sysfs_nvme = sysfs_tree / "sys" / "class" / "nvme" / "nvme0"
+        # Both endpoints display as 01:30 locally, on opposite UTC offsets.
+        first_at = datetime(2026, 11, 1, 5, 30, tzinfo=timezone.utc)
+        second_at = datetime(2026, 11, 1, 6, 30, tzinfo=timezone.utc)
+        assert run_collection(
+            _make_smartctl(10_000_000, 8_000_000),
+            sysfs_nvme,
+            cfg,
+            _Clock(first_at),
+        )["ok"]
+        assert run_collection(
+            _make_smartctl(10_000_001, 8_000_002),
+            sysfs_nvme,
+            cfg,
+            _Clock(second_at),
+        )["ok"]
+
+        conn = sqlite3.connect(store)
+        summary = query_local_day_summary(
+            conn, "2026-11-01", "America/New_York", second_at
+        )
+        assert summary is not None
+        assert summary["bytes_written"] == 512_000
+        assert summary["bytes_read"] == 1_024_000
+        assert summary["utc_start"] == "2026-11-01T04:00:00+00:00"
+        assert summary["utc_end"] == "2026-11-02T05:00:00+00:00"
+        conn.close()

tests/test_measured_activity.py

@@ -0,0 +1,551 @@
+"""Measured drive activity integration tests (issue #89).
+
+Drives successive controlled acquisition readings through the public
+collector into a real temporary observation store, then verifies the
+normal reader and visible dashboard report correct read/write deltas,
+hour/day evidence, accumulation, and boundary behaviour.
+
+Seams:
+- write side: run_collection() → observation store
+- read side: _query_daily_graph_data(), _query_hourly_graph_data(),
+             derive_day(), get_status() → observation store
+"""
+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
+from fenris.store import init_store
+from fenris.day_aggregate import derive_day
+from fenris.monitoring_periods import ensure_period_open
+from fenris.tui import _query_daily_graph_data, _query_hourly_graph_data
+
+
+# ---------------------------------------------------------------------------
+# Fixtures
+# ---------------------------------------------------------------------------
+
+def _make_smartctl(duw: int, dur: int) -> Dict[str, Any]:
+    """Build a smartctl fixture with specific DUW/DUR counters."""
+    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,
+            "data_units_read": dur, "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_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
+
+
+class _Clock:
+    """Injected clock returning controlled time."""
+    def __init__(self, initial: datetime):
+        self.now = initial
+    def utcnow(self):
+        return self.now
+
+
+# ---------------------------------------------------------------------------
+# AC1: Two successive readings produce correct read/write deltas
+# visible through both the hour observations and the TUI query path.
+# ---------------------------------------------------------------------------
+
+class TestSuccessiveReadings:
+    """First reading is an anchor; second yields a measured interval."""
+
+    def test_two_readings_produce_both_rw_deltas(
+        self, tmp_path, sysfs_tree,
+    ):
+        t1 = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        t2 = datetime(2026, 9, 1, 12, 5, 0, tzinfo=timezone.utc)
+        store = str(tmp_path / "obs.db")
+        cfg = {"device": "/dev/nvme0", "store_path": store}
+        sysfs_nvme = sysfs_tree / "sys" / "class" / "nvme" / "nvme0"
+
+        # DUW=10000000, DUR=8000000
+        r1 = run_collection(_make_smartctl(10000000, 8000000), sysfs_nvme, cfg, _Clock(t1))
+        assert r1["ok"]
+        # +50 DUW, +30 DUR
+        r2 = run_collection(_make_smartctl(10000050, 8000030), sysfs_nvme, cfg, _Clock(t2))
+        assert r2["ok"]
+
+        conn = sqlite3.connect(store)
+        # Hour observation should have both read and write deltas
+        hour = conn.execute(
+            "SELECT bytes_written_delta, bytes_read_delta "
+            "FROM hour_observations WHERE hour LIKE '2026-09-01T12%'"
+        ).fetchone()
+        assert hour is not None
+        assert hour[0] == 50 * 512000  # writes
+        assert hour[1] == 30 * 512000  # reads
+
+        # TUI graph query should report both
+        daily = _query_daily_graph_data(conn)
+        assert len(daily) >= 1
+        day_entry = daily[-1]
+        bw_expected = 50 * 512000
+        br_expected = 30 * 512000
+        assert day_entry["total_written"] == bw_expected
+        assert day_entry["total_read"] == br_expected
+        assert day_entry["allocated_bytes"] == bw_expected
+        assert day_entry["allocated_read"] == br_expected
+        conn.close()
+
+    def test_first_reading_is_anchor_no_delta(
+        self, tmp_path, sysfs_tree,
+    ):
+        """First sample alone produces no hour observation or day aggregate."""
+        t1 = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        store = str(tmp_path / "obs.db")
+        cfg = {"device": "/dev/nvme0", "store_path": store}
+        sysfs_nvme = sysfs_tree / "sys" / "class" / "nvme" / "nvme0"
+
+        run_collection(_make_smartctl(10000000, 8000000), sysfs_nvme, cfg, _Clock(t1))
+
+        conn = sqlite3.connect(store)
+        assert conn.execute("SELECT COUNT(*) FROM samples").fetchone()[0] == 1
+        assert conn.execute("SELECT COUNT(*) FROM hour_observations").fetchone()[0] == 0
+        daily = _query_daily_graph_data(conn)
+        assert all(d["is_zero"] or d["is_gap"] for d in daily)
+        conn.close()
+
+
+# ---------------------------------------------------------------------------
+# AC3: Repeated same-hour collections accumulate both reads and writes
+# ---------------------------------------------------------------------------
+
+class TestSameHourAccumulation:
+    """Multiple intervals in the same hour accumulate both BW and BR."""
+
+    def test_three_same_hour_readings_accumulate(self, tmp_path, sysfs_tree):
+        store = str(tmp_path / "obs.db")
+        cfg = {"device": "/dev/nvme0", "store_path": store}
+        sysfs_nvme = sysfs_tree / "sys" / "class" / "nvme" / "nvme0"
+        base_t = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+
+        # Three readings: 0→20→50 DUW, 0→10→35 DUR (all same hour)
+        duw_seq = [10000000, 10000020, 10000050]
+        dur_seq = [8000000, 8000010, 8000035]
+        for i in range(3):
+            t = base_t + timedelta(minutes=i * 3)
+            r = run_collection(
+                _make_smartctl(duw_seq[i], dur_seq[i]), sysfs_nvme, cfg, _Clock(t)
+            )
+            assert r["ok"]
+
+        conn = sqlite3.connect(store)
+        hour = conn.execute(
+            "SELECT bytes_written_delta, bytes_read_delta, sample_count "
+            "FROM hour_observations WHERE hour LIKE '2026-09-01T12%'"
+        ).fetchone()
+        assert hour is not None
+        # 0→20 + 20→50 = 50 DUW delta
+        assert hour[0] == 50 * 512000
+        # 0→10 + 10→35 = 35 DUR delta
+        assert hour[1] == 35 * 512000
+        # 2 intervals × 2 samples each = 4 sample_count
+        assert hour[2] == 4
+        conn.close()
+
+    def test_same_hour_zero_delta_both_counters(
+        self, tmp_path, sysfs_tree,
+    ):
+        """Repeated identical readings produce zero in both BW and BR."""
+        store = str(tmp_path / "obs.db")
+        cfg = {"device": "/dev/nvme0", "store_path": store}
+        sysfs_nvme = sysfs_tree / "sys" / "class" / "nvme" / "nvme0"
+        base_t = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+
+        for i in range(3):
+            t = base_t + timedelta(minutes=i * 3)
+            r = run_collection(
+                _make_smartctl(10000000, 8000000), sysfs_nvme, cfg, _Clock(t)
+            )
+            assert r["ok"]
+
+        conn = sqlite3.connect(store)
+        hour = conn.execute(
+            "SELECT bytes_written_delta, bytes_read_delta "
+            "FROM hour_observations WHERE hour LIKE '2026-09-01T12%'"
+        ).fetchone()
+        assert hour is not None
+        assert hour[0] == 0
+        assert hour[1] == 0
+        conn.close()
+
+
+# ---------------------------------------------------------------------------
+# AC4: Cross-hour measurements attributed to correct hours
+# ---------------------------------------------------------------------------
+
+class TestCrossHourAttribution:
+    """Cross-hour deltas are unattributed to hours, kept at day level."""
+
+    def test_cross_hour_unattributed_bytes(
+        self, tmp_path, sysfs_tree,
+    ):
+        store = str(tmp_path / "obs.db")
+        cfg = {"device": "/dev/nvme0", "store_path": store}
+        sysfs_nvme = sysfs_tree / "sys" / "class" / "nvme" / "nvme0"
+
+        t1 = datetime(2026, 9, 1, 11, 55, 0, tzinfo=timezone.utc)
+        t2 = datetime(2026, 9, 1, 12, 5, 0, tzinfo=timezone.utc)
+
+        r1 = run_collection(_make_smartctl(10000000, 8000000), sysfs_nvme, cfg, _Clock(t1))
+        assert r1["ok"]
+        r2 = run_collection(_make_smartctl(10000100, 8000060), sysfs_nvme, cfg, _Clock(t2))
+        assert r2["ok"]
+
+        conn = sqlite3.connect(store)
+
+        # Hour 11 and 12 should NOT contain the full cross-hour delta
+        full_bw = 100 * 512000
+        full_br = 60 * 512000
+        for prefix in ("2026-09-01T11%", "2026-09-01T12%"):
+            row = conn.execute(
+                "SELECT bytes_written_delta, bytes_read_delta "
+                "FROM hour_observations WHERE hour LIKE ?", (prefix,)
+            ).fetchone()
+            if row is not None:
+                assert row[0] != full_bw, "Hour should not have full cross-hour BW"
+                assert row[1] != full_br, "Hour should not have full cross-hour BR"
+
+        # Day aggregates should have unattributed bytes for both reads and writes
+        for day in ("2026-09-01",):
+            agg = derive_day(conn, day)
+            assert agg is not None
+            total_accounted = agg.bytes_written_delta + agg.bytes_read_delta
+            unattributed_w = conn.execute(
+                "SELECT unattributed_bytes_written FROM day_aggregates WHERE day = ?",
+                (day,)
+            ).fetchone()
+            unattributed_r = conn.execute(
+                "SELECT unattributed_bytes_read FROM day_aggregates WHERE day = ?",
+                (day,)
+            ).fetchone()
+            # Unattributed bytes should be present
+            assert unattributed_w is not None
+            assert unattributed_r is not None
+        conn.close()
+
+
+# ---------------------------------------------------------------------------
+# AC5: Repeated refresh does not duplicate measured bytes
+# ---------------------------------------------------------------------------
+
+class TestNoDuplication:
+    """Repeated collection does not duplicate measured bytes."""
+
+    def test_multiple_same_hour_no_duplication(
+        self, tmp_path, sysfs_tree,
+    ):
+        """Five same-hour reads, all monotonic: bytes never double-count."""
+        store = str(tmp_path / "obs.db")
+        cfg = {"device": "/dev/nvme0", "store_path": store}
+        sysfs_nvme = sysfs_tree / "sys" / "class" / "nvme" / "nvme0"
+        base_t = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+
+        # Monotonically increasing DUW: 100, 110, 125, 145, 180
+        duw_increments = [0, 10, 15, 20, 35]
+        dur_increments = [0, 5, 8, 12, 20]
+        for i in range(5):
+            duw = 10000000 + sum(duw_increments[:i + 1])
+            dur = 8000000 + sum(dur_increments[:i + 1])
+            t = base_t + timedelta(minutes=i * 2)
+            r = run_collection(_make_smartctl(duw, dur), sysfs_nvme, cfg, _Clock(t))
+            assert r["ok"]
+
+        conn = sqlite3.connect(store)
+        hour = conn.execute(
+            "SELECT bytes_written_delta, bytes_read_delta "
+            "FROM hour_observations WHERE hour LIKE '2026-09-01T12%'"
+        ).fetchone()
+        assert hour is not None
+        # Total should be the cumulative delta across all 5 readings
+        total_duw_delta = sum(duw_increments)
+        total_dur_delta = sum(dur_increments)
+        assert hour[0] == total_duw_delta * 512000
+        assert hour[1] == total_dur_delta * 512000
+        conn.close()
+
+
+# ---------------------------------------------------------------------------
+# AC: Consistent read-only snapshot
+# ---------------------------------------------------------------------------
+
+class TestConcurrentReadConsistency:
+    """A read-only reader sees consistent pre- or post-publication state."""
+
+    def test_read_only_sees_consistent_state(
+        self, tmp_path, sysfs_tree,
+    ):
+        t1 = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        t2 = datetime(2026, 9, 1, 12, 5, 0, tzinfo=timezone.utc)
+        store = str(tmp_path / "obs.db")
+        cfg = {"device": "/dev/nvme0", "store_path": store}
+        sysfs_nvme = sysfs_tree / "sys" / "class" / "nvme" / "nvme0"
+
+        run_collection(_make_smartctl(10000000, 8000000), sysfs_nvme, cfg, _Clock(t1))
+
+        # Open read-only before second sample
+        ro_conn = sqlite3.connect("file:%s?mode=ro" % store, uri=True)
+        ro_conn.execute("BEGIN")
+        count_before = ro_conn.execute("SELECT COUNT(*) FROM samples").fetchone()[0]
+        assert count_before == 1
+        ro_conn.close()
+
+        run_collection(_make_smartctl(10000050, 8000030), sysfs_nvme, cfg, _Clock(t2))
+
+        # Read-only after second sample sees updated state
+        ro_conn2 = sqlite3.connect("file:%s?mode=ro" % store, uri=True)
+        ro_conn2.execute("BEGIN")
+        count_after = ro_conn2.execute("SELECT COUNT(*) FROM samples").fetchone()[0]
+        assert count_after == 2
+        ro_conn2.close()
+
+
+# ---------------------------------------------------------------------------
+# AC: Counter reset / segment boundary
+# ---------------------------------------------------------------------------
+
+class TestCounterResetPreservesHistory:
+    """Counter reset opens new segment without invalidating prior data."""
+
+    def test_duw_decrease_preserves_hour_data(
+        self, tmp_path, sysfs_tree,
+    ):
+        t1 = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        t2 = datetime(2026, 9, 1, 12, 5, 0, tzinfo=timezone.utc)
+        t3 = datetime(2026, 9, 1, 12, 10, 0, tzinfo=timezone.utc)
+        store = str(tmp_path / "obs.db")
+        cfg = {"device": "/dev/nvme0", "store_path": store}
+        sysfs_nvme = sysfs_tree / "sys" / "class" / "nvme" / "nvme0"
+
+        # Sample 1: normal
+        run_collection(_make_smartctl(10000100, 8000060), sysfs_nvme, cfg, _Clock(t1))
+        # Sample 2: counter decrease (reset)
+        run_collection(_make_smartctl(10000050, 8000030), sysfs_nvme, cfg, _Clock(t2))
+        # Sample 3: new segment continuation
+        run_collection(_make_smartctl(10000080, 8000050), sysfs_nvme, cfg, _Clock(t3))
+
+        conn = sqlite3.connect(store)
+
+        # New segment opened for the reset
+        seg_count = conn.execute("SELECT COUNT(*) FROM controller_segments").fetchone()[0]
+        assert seg_count >= 2
+
+        # The reset sample (t2) is in a new segment; t3 derives from t2
+        hour_12 = conn.execute(
+            "SELECT bytes_written_delta, bytes_read_delta "
+            "FROM hour_observations WHERE hour LIKE '2026-09-01T12%'"
+        ).fetchone()
+        assert hour_12 is not None
+        # Hour 12 should have data from at least the valid interval (t2→t3)
+        # t2→t3: 10000080-10000050=30 DUW, 8000050-8000030=20 DUR
+        assert hour_12[0] >= 30 * 512000
+        assert hour_12[1] >= 20 * 512000
+        conn.close()
+
+
+# ---------------------------------------------------------------------------
+# AC: Monitoring period is opened and preserved
+# ---------------------------------------------------------------------------
+
+class TestMonitoringPeriodPreserved:
+    """Collector opens monitoring period; subsequent samples keep it open."""
+
+    def test_first_sample_opens_period(self, tmp_path, sysfs_tree):
+        t1 = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        store = str(tmp_path / "obs.db")
+        cfg = {"device": "/dev/nvme0", "store_path": store}
+        sysfs_nvme = sysfs_tree / "sys" / "class" / "nvme" / "nvme0"
+
+        run_collection(_make_smartctl(10000000, 8000000), sysfs_nvme, cfg, _Clock(t1))
+
+        conn = sqlite3.connect(store)
+        period = conn.execute(
+            "SELECT COUNT(*) FROM monitoring_periods"
+        ).fetchone()[0]
+        conn.close()
+        assert period == 1
+
+    def test_subsequent_samples_keep_one_period(
+        self, tmp_path, sysfs_tree,
+    ):
+        t1 = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        t2 = datetime(2026, 9, 1, 12, 5, 0, tzinfo=timezone.utc)
+        store = str(tmp_path / "obs.db")
+        cfg = {"device": "/dev/nvme0", "store_path": store}
+        sysfs_nvme = sysfs_tree / "sys" / "class" / "nvme" / "nvme0"
+
+        run_collection(_make_smartctl(10000000, 8000000), sysfs_nvme, cfg, _Clock(t1))
+        run_collection(_make_smartctl(10000050, 8000030), sysfs_nvme, cfg, _Clock(t2))
+
+        conn = sqlite3.connect(store)
+        period_count = conn.execute(
+            "SELECT COUNT(*) FROM monitoring_periods"
+        ).fetchone()[0]
+        conn.close()
+        assert period_count == 1
+
+
+# ---------------------------------------------------------------------------
+# AC: Derivation failure preserves sample
+# ---------------------------------------------------------------------------
+
+class TestDerivationFailurePreservesSample:
+    """Sample persists even if derivation fails."""
+
+    def test_sample_survives_derivation_failure(
+        self, tmp_path, sysfs_tree,
+    ):
+        t1 = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        t2 = datetime(2026, 9, 1, 12, 5, 0, tzinfo=timezone.utc)
+        store = str(tmp_path / "obs.db")
+        cfg = {"device": "/dev/nvme0", "store_path": store}
+        sysfs_nvme = sysfs_tree / "sys" / "class" / "nvme" / "nvme0"
+
+        run_collection(_make_smartctl(10000000, 8000000), sysfs_nvme, cfg, _Clock(t1))
+
+        # Second sample succeeds normally
+        r2 = run_collection(
+            _make_smartctl(10000050, 8000030), sysfs_nvme, cfg, _Clock(t2)
+        )
+        assert r2["ok"]
+
+        conn = sqlite3.connect(store)
+        count = conn.execute("SELECT COUNT(*) FROM samples").fetchone()[0]
+        conn.close()
+        assert count == 2
+
+
+# ---------------------------------------------------------------------------
+# AC: Cross-day UTC boundary
+# ---------------------------------------------------------------------------
+
+class TestCrossDayBoundary:
+    """Measurements crossing UTC day boundary are conserved."""
+
+    def test_cross_day_unattributed_both_days(
+        self, tmp_path, sysfs_tree,
+    ):
+        t1 = datetime(2026, 9, 1, 23, 55, 0, tzinfo=timezone.utc)
+        t2 = datetime(2026, 9, 2, 0, 5, 0, tzinfo=timezone.utc)
+        store = str(tmp_path / "obs.db")
+        cfg = {"device": "/dev/nvme0", "store_path": store}
+        sysfs_nvme = sysfs_tree / "sys" / "class" / "nvme" / "nvme0"
+
+        r1 = run_collection(_make_smartctl(10000000, 8000000), sysfs_nvme, cfg, _Clock(t1))
+        assert r1["ok"]
+        r2 = run_collection(_make_smartctl(10000100, 8000060), sysfs_nvme, cfg, _Clock(t2))
+        assert r2["ok"]
+
+        conn = sqlite3.connect(store)
+        daily = _query_daily_graph_data(conn)
+        day_map = {d["day"]: d for d in daily}
+
+        # Both days should appear
+        assert "2026-09-01" in day_map
+        assert "2026-09-02" in day_map
+
+        # The cross-day delta is unattributed at the day level
+        sep1 = day_map["2026-09-01"]
+        sep2 = day_map["2026-09-02"]
+        # Both days may show the unattributed bytes
+        # (the delta is added to both days' unattributed totals as evidence)
+        total_w = sep1["allocated_bytes"] + sep1["unallocated_bytes"]
+        total_r = sep1["allocated_read"] + sep1["unallocated_read"]
+        # Day 1 has at least some recorded data
+        assert total_w >= 0
+        assert total_r >= 0
+        conn.close()
+
+
+# ---------------------------------------------------------------------------
+# AC: Hourly graph query includes read data
+# ---------------------------------------------------------------------------
+
+class TestHourlyQueryIncludesReads:
+    """Hourly graph data includes bytes_read_delta."""
+
+    def test_hourly_query_returns_read_data(
+        self, tmp_path, sysfs_tree,
+    ):
+        t1 = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        t2 = datetime(2026, 9, 1, 12, 5, 0, tzinfo=timezone.utc)
+        store = str(tmp_path / "obs.db")
+        cfg = {"device": "/dev/nvme0", "store_path": store}
+        sysfs_nvme = sysfs_tree / "sys" / "class" / "nvme" / "nvme0"
+
+        run_collection(_make_smartctl(10000000, 8000000), sysfs_nvme, cfg, _Clock(t1))
+        run_collection(_make_smartctl(10000050, 8000030), sysfs_nvme, cfg, _Clock(t2))
+
+        conn = sqlite3.connect(store)
+        hourly = _query_hourly_graph_data(conn, "2026-09-01", t2)
+
+        # Hour 12 should have read data
+        h12 = next(h for h in hourly if h["hour"] == "2026-09-01T12:00:00+00:00")
+        assert h12["bytes_written"] == 50 * 512000
+        assert h12["bytes_read"] == 30 * 512000
+        conn.close()
+
+
+# ---------------------------------------------------------------------------
+# AC: Day aggregate derivation surfaces both read/write
+# ---------------------------------------------------------------------------
+
+class TestDayAggregateReadWrite:
+    """Day aggregate includes both read and write deltas."""
+
+    def test_derive_day_shows_both_rw(
+        self, tmp_path, sysfs_tree,
+    ):
+        t1 = datetime(2026, 9, 1, 12, 0, 0, tzinfo=timezone.utc)
+        t2 = datetime(2026, 9, 1, 12, 5, 0, tzinfo=timezone.utc)
+        store = str(tmp_path / "obs.db")
+        cfg = {"device": "/dev/nvme0", "store_path": store}
+        sysfs_nvme = sysfs_tree / "sys" / "class" / "nvme" / "nvme0"
+
+        run_collection(_make_smartctl(10000000, 8000000), sysfs_nvme, cfg, _Clock(t1))
+        run_collection(_make_smartctl(10000050, 8000030), sysfs_nvme, cfg, _Clock(t2))
+
+        conn = sqlite3.connect(store)
+        day = derive_day(conn, "2026-09-01")
+        assert day is not None
+        assert day.bytes_written_delta == 50 * 512000
+        assert day.bytes_read_delta == 30 * 512000
+        assert day.sample_count >= 2
+        conn.close()

tests/test_package_stage.py

@@ -0,0 +1,43 @@
+"""Package directory permissions must not inherit a builder's private umask."""
+import os
+import shutil
+import subprocess
+import sys
+from pathlib import Path
+
+import pytest
+
+
+@pytest.mark.parametrize("mask", ["077", "022"])
+def test_stage_is_publicly_traversable_under_any_builder_umask(tmp_path, mask):
+    root = Path(__file__).resolve().parent.parent
+    for directory in ("packaging", "scripts", "src", "units", "polkit"):
+        shutil.copytree(root / directory, tmp_path / directory,
+                        ignore=shutil.ignore_patterns("__pycache__", "*.egg-info"))
+    for filename in ("LICENSE", "requirements.txt"):
+        shutil.copy(root / filename, tmp_path / filename)
+    (tmp_path / "dist").mkdir()
+    (tmp_path / "dist/fenris-9.9.9-py3-none-any.whl").touch()
+    bin_dir = tmp_path / "bin"
+    bin_dir.mkdir()
+    # Avoid downloading dependencies: emulate pip's target output while
+    # exercising the real staging script and its package directory layout.
+    pip_stub = bin_dir / "python3"
+    pip_stub.write_text(
+        f"#!{sys.executable}\n"
+        "import sys\nfrom pathlib import Path\n"
+        "target = Path(sys.argv[sys.argv.index('--target') + 1]) / 'fenris'\n"
+        "target.mkdir(parents=True)\n"
+        "(target / '__init__.py').write_text('')\n"
+    )
+    pip_stub.chmod(0o755)
+    subprocess.run(
+        ["bash", "-c", f"umask {mask}; exec bash packaging/stage.sh 9.9.9"],
+        cwd=tmp_path, env={**os.environ, "PATH": str(bin_dir) + os.pathsep + os.environ["PATH"]},
+        check=True, capture_output=True, text=True,
+    )
+    stage = tmp_path / "build/stage"
+    for directory in (stage, *(p for p in stage.rglob("*") if p.is_dir())):
+        assert directory.stat().st_mode & 0o777 == 0o755, directory
+    assert (stage / "usr/bin/fenris").stat().st_mode & 0o777 == 0o755
+    assert (stage / "opt/fenris/vendor/fenris/__init__.py").stat().st_mode & 0o444 == 0o444

tests/test_preferences.py

@@ -3,7 +3,7 @@
 Covers:
   - Preference load/save with safe defaults
   - XDG_CONFIG_HOME user-scoped persistence
-  - Amber default theme, normal-motion default
+  - Chalktone default theme, normal-motion default
   - Invalid/unreadable/unwritable preference data does not crash
   - Theme presets: Amber, Nord, High Contrast
   - Reduced motion preference persistence
@@ -72,9 +72,9 @@ class TestPreferencePath:
 class TestDefaults:
     """When no preference file exists, defaults are returned."""
 
-    def test_default_theme_is_amber(self):
+    def test_default_theme_is_chalktone(self):
         """Amber is the default theme preset."""
-        assert DEFAULT_THEME == "amber"
+        assert DEFAULT_THEME == "chalktone"
 
     def test_default_reduced_motion_is_false(self):
         """Normal motion is the default."""
@@ -82,13 +82,13 @@ class TestDefaults:
 
     def test_valid_themes_are_all_presets(self):
         """Three valid presets exist."""
-        assert VALID_THEMES == {"amber", "nord", "high_contrast"}
+        assert VALID_THEMES == {"chalktone", "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["theme"] == "chalktone"
             assert prefs["reduced_motion"] is False
 
 
@@ -151,7 +151,7 @@ class TestSafeFailures:
 
         with patch.dict(os.environ, {"XDG_CONFIG_HOME": str(config_home)}):
             prefs = load_preferences()
-            assert prefs["theme"] == "amber"
+            assert prefs["theme"] == "chalktone"
             assert prefs["reduced_motion"] is False
 
     def test_unknown_theme_returns_default(self, tmp_path):
@@ -165,7 +165,7 @@ class TestSafeFailures:
 
         with patch.dict(os.environ, {"XDG_CONFIG_HOME": str(config_home)}):
             prefs = load_preferences()
-            assert prefs["theme"] == "amber"
+            assert prefs["theme"] == "chalktone"
 
     def test_missing_keys_get_defaults(self, tmp_path):
         """Partial preference file fills in missing keys."""
@@ -218,7 +218,7 @@ class TestSafeFailures:
 
         with patch.dict(os.environ, {"XDG_CONFIG_HOME": str(config_home)}):
             prefs = load_preferences()
-            assert prefs["theme"] == "amber"
+            assert prefs["theme"] == "chalktone"
 
     def test_wrong_type_for_reduced_motion(self, tmp_path):
         """Non-boolean reduced_motion falls back to default."""

tests/test_projection.py

@@ -88,6 +88,33 @@ def _open_period(conn, start="2026-09-01T00:00:00+00:00"):
     ensure_period_open(conn, datetime.fromisoformat(start))
 
 
+def _insert_local_day(conn, local_date, tz_name="UTC", tz_offset="+00:00",
+                       utc_start=None, utc_end=None, bw=1024*1024*100,
+                       br=0, coverage=0.95, samples=24, complete=True):
+    """Insert a local_days row (issue #94 gate prerequisite)."""
+    if utc_start is None:
+        utc_start = local_date + "T00:00:00+00:00"
+    if utc_end is None:
+        dt = datetime.strptime(local_date, "%Y-%m-%d") + timedelta(days=1)
+        utc_end = dt.strftime("%Y-%m-%dT00:00:00+00:00")
+    conn.execute(
+        "INSERT INTO local_days "
+        "(local_date, tz_name, tz_offset, utc_start, utc_end, "
+        " bytes_written, bytes_read, coverage, sample_count, complete, activity_intervals) "
+        "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, 1)",
+        (local_date, tz_name, tz_offset, utc_start, utc_end,
+         bw, br, coverage, samples, complete),
+    )
+    conn.commit()
+
+
+def _insert_complete_local_days(conn, start_date, count, bw=1024*1024*100):
+    """Insert multiple complete local days to satisfy the issue #94 gate."""
+    for i in range(count):
+        d = (datetime.strptime(start_date, "%Y-%m-%d") + timedelta(days=i)).strftime("%Y-%m-%d")
+        _insert_local_day(conn, d, bw=bw)
+
+
 class TestPrecedence:
     def test_no_baseline_unavailable(self, store):
         _insert_segment(store)
@@ -127,6 +154,7 @@ class TestConfidenceRuleTable:
     def test_unavailable_no_baseline(self, store):
         _insert_segment(store)
         _open_period(store)
+        _insert_complete_local_days(store, "2026-09-29", 1)
         result = compute_projection(store, _clock())
         assert result.confidence_state == ConfidenceState.UNSUPPORTED
         assert any("no applicable endurance baseline" in f for f in result.contributing_facts)
@@ -138,6 +166,7 @@ class TestConfidenceRuleTable:
         for i in range(20):
             d = (datetime(2026, 9, 10) + timedelta(days=i)).strftime("%Y-%m-%d")
             _insert_day(store, d, bw=0)
+        _insert_complete_local_days(store, "2026-09-29", 1)
         result = compute_projection(store, _clock())
         assert result.confidence_state == ConfidenceState.UNSUPPORTED
         assert any("no finite projection" in f for f in result.contributing_facts)
@@ -150,12 +179,14 @@ class TestConfidenceRuleTable:
             d = (datetime(2026, 9, 25) + timedelta(days=i)).strftime("%Y-%m-%d")
             _insert_day(store, d, bw=1024*1024*100)
         _insert_sample(store, "2026-09-30T10:00:00+00:00", pu=5)
+        _insert_complete_local_days(store, "2026-09-29", 1)
         result = compute_projection(store, _clock())
         assert result.confidence_state == ConfidenceState.LIMITED
         assert any("regime only" in f and "days old" in f for f in result.contributing_facts)
 
     def test_limited_degraded_identity(self, store):
         _insert_baseline(store, tbw_tb=1.0, verified=True)
+        _insert_complete_local_days(store, "2026-09-29", 1)
         _insert_segment(store, degraded=True)
         _open_period(store)
         for i in range(20):
@@ -201,6 +232,7 @@ class TestZeroRate:
         for i in range(20):
             d = (datetime(2026, 9, 10) + timedelta(days=i)).strftime("%Y-%m-%d")
             _insert_day(store, d, bw=0)
+        _insert_complete_local_days(store, "2026-09-29", 1)
         result = compute_projection(store, _clock())
         assert result.confidence_state == ConfidenceState.UNSUPPORTED
         assert any("no finite projection from this history" in f for f in result.contributing_facts)
@@ -385,6 +417,7 @@ class TestSustainedRegimeRate:
             d = (datetime(2026, 6, 1) + timedelta(days=i)).strftime("%Y-%m-%d")
             _insert_day(store, d, bw=bw)
         _insert_sample(store, "2026-09-28T12:00:00+00:00", pu=5)
+        _insert_complete_local_days(store, "2026-09-29", 1)
         result = compute_projection(store, _clock(year=2026, month=9, day=30, hour=12))
         # Regime should be capped at 90 days (from Jun 1 to Sep 30 = 90 days at cutoff)
         # The 90-day cutoff is Sep 30 - 90 = Jul 1, so regime starts Jul 1
@@ -447,6 +480,7 @@ class TestHabitChange:
             d = (datetime(2026, 8, 29) + timedelta(days=i)).strftime("%Y-%m-%d")
             _insert_day(store, d, bw=bw_high)
         _insert_sample(store, "2026-09-08T10:00:00+00:00", pu=5)
+        _insert_complete_local_days(store, "2026-09-07", 1)
         result = compute_projection(store, _clock(year=2026, month=9, day=8, hour=12))
         assert result.habit_change_fact is not None
         assert "usage habit changed" in result.habit_change_fact
@@ -468,6 +502,7 @@ class TestHabitChange:
             d = (datetime(2026, 8, 29) + timedelta(days=i)).strftime("%Y-%m-%d")
             _insert_day(store, d, bw=bw_low)
         _insert_sample(store, "2026-09-08T10:00:00+00:00", pu=5)
+        _insert_complete_local_days(store, "2026-09-07", 1)
         result = compute_projection(store, _clock(year=2026, month=9, day=8, hour=12))
         assert result.habit_change_fact is not None
         assert "usage habit changed" in result.habit_change_fact
@@ -524,6 +559,7 @@ class TestHabitChange:
             d = (datetime(2026, 9, 25) + timedelta(days=i)).strftime("%Y-%m-%d")
             _insert_day(store, d, bw=bw)
         _insert_sample(store, "2026-09-30T10:00:00+00:00", pu=5)
+        _insert_complete_local_days(store, "2026-09-29", 1)
         result = compute_projection(store, _clock())
         assert result.confidence_state == ConfidenceState.LIMITED
         assert any("regime only" in f and "days old" in f for f in result.contributing_facts)
@@ -544,6 +580,7 @@ class TestWarmingGate:
             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)
+        _insert_complete_local_days(store, "2026-09-29", 1)
         result = compute_projection(store, _clock())
         assert result.warming_fact is not None
         assert "warming up" in result.warming_fact
@@ -560,6 +597,7 @@ class TestWarmingGate:
             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)
+        _insert_complete_local_days(store, "2026-09-29", 1)
         result = compute_projection(store, _clock())
         assert result.warming_fact is not None
         assert "warming up" in result.warming_fact
@@ -589,6 +627,7 @@ class TestWarmingGate:
             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)
+        _insert_complete_local_days(store, "2026-09-29", 1)
         result = compute_projection(store, _clock())
         assert result.warming_fact is not None
 
@@ -602,6 +641,7 @@ class TestWarmingGate:
             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)
+        _insert_complete_local_days(store, "2026-09-29", 1)
         result = compute_projection(store, _clock())
         # Should have warming fact but still render
         assert result.warming_fact is not None
@@ -614,6 +654,7 @@ class TestWarmingGate:
         _insert_segment(store)
         _open_period(store)
         _insert_day(store, "2026-09-28", bw=100*1024*1024)
+        _insert_complete_local_days(store, "2026-09-29", 1)
         result = compute_projection(store, _clock())
         assert result.confidence_state == ConfidenceState.UNSUPPORTED
         assert result.headline_remaining_seconds is None
@@ -626,6 +667,7 @@ class TestWarmingGate:
         for i in range(20):
             d = (datetime(2026, 9, 10) + timedelta(days=i)).strftime("%Y-%m-%d")
             _insert_day(store, d, bw=0)
+        _insert_complete_local_days(store, "2026-09-29", 1)
         result = compute_projection(store, _clock())
         assert result.confidence_state == ConfidenceState.UNSUPPORTED
         assert result.headline_remaining_seconds is None
@@ -646,6 +688,7 @@ class TestStalenessDrop:
             d = (datetime(2026, 9, 1) + 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)
+        _insert_complete_local_days(store, "2026-09-29", 1)
         # Clock is 3 days after last data → staleness > 48h
         clock = datetime(2026, 10, 3, 12, 0, 0, tzinfo=timezone.utc)
         result = compute_projection(store, clock)
@@ -661,6 +704,7 @@ class TestStalenessDrop:
             d = (datetime(2026, 9, 1) + 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)
+        _insert_complete_local_days(store, "2026-09-29", 1)
         clock = datetime(2026, 10, 3, 12, 0, 0, tzinfo=timezone.utc)
         result = compute_projection(store, clock)
         assert result.staleness_fact is not None
@@ -703,6 +747,7 @@ class TestSegmentBreakProjection:
             d = (datetime(2026, 9, 16) + timedelta(days=i)).strftime("%Y-%m-%d")
             _insert_day(store, d, bw=bw)
         _insert_sample(store, "2026-09-20T10:00:00+00:00", pu=5)
+        _insert_complete_local_days(store, "2026-09-19", 1)
         result = compute_projection(store, _clock(year=2026, month=9, day=20, hour=12))
         # Prior days exist in store but projection uses current segment
         # 5 days in segment → regime_days = 5
@@ -727,6 +772,7 @@ class TestSegmentBreakProjection:
             d = (datetime(2026, 9, 25) + timedelta(days=i)).strftime("%Y-%m-%d")
             _insert_day(store, d, bw=bw)
         _insert_sample(store, "2026-09-28T10:00:00+00:00", pu=5)
+        _insert_complete_local_days(store, "2026-09-27", 1)
         result = compute_projection(store, _clock(year=2026, month=9, day=28, hour=12))
         # Young regime (3 days) → Limited, not enough data for full confidence
         assert result.confidence_state == ConfidenceState.LIMITED
@@ -753,6 +799,7 @@ class TestSegmentBreakProjection:
             d = (datetime(2026, 9, 25) + timedelta(days=i)).strftime("%Y-%m-%d")
             _insert_day(store, d, bw=bw)
         _insert_sample(store, "2026-09-28T10:00:00+00:00", pu=5)
+        _insert_complete_local_days(store, "2026-09-27", 1)
         result = compute_projection(store, _clock(year=2026, month=9, day=28, hour=12))
         # Prior history quarantined; only 3 days in new segment
         assert result.regime_days is not None
@@ -771,6 +818,7 @@ class TestDegradedIdentity:
         _insert_segment(store, identity_key=None, degraded=True)
         _open_period(store)
         _insert_day(store, "2026-09-28", bw=100*1024*1024)
+        _insert_complete_local_days(store, "2026-09-29", 1)
         # No baseline → Unavailable
         result = compute_projection(store, _clock())
         assert result.confidence_state == ConfidenceState.UNSUPPORTED
@@ -787,6 +835,7 @@ class TestDegradedIdentity:
             d = (datetime(2026, 9, 1) + 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)
+        _insert_complete_local_days(store, "2026-09-29", 1)
         result = compute_projection(store, _clock())
         assert result.confidence_state == ConfidenceState.LIMITED
         assert any("controller identity unavailable" in f for f in result.contributing_facts)
@@ -802,6 +851,7 @@ class TestDegradedIdentity:
             d = (datetime(2026, 9, 1) + 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)
+        _insert_complete_local_days(store, "2026-09-29", 1)
         # Stale clock (>48h)
         clock = datetime(2026, 10, 5, 12, 0, 0, tzinfo=timezone.utc)
         result = compute_projection(store, clock)
@@ -857,6 +907,7 @@ class TestIdentityChangeBlankKeys:
             d = (datetime(2026, 9, 21) + timedelta(days=i)).strftime("%Y-%m-%d")
             _insert_day(store, d, bw=bw)
         _insert_sample(store, "2026-09-26T10:00:00+00:00", pu=5)
+        _insert_complete_local_days(store, "2026-09-25", 1)
         result = compute_projection(store, _clock(year=2026, month=9, day=26, hour=12))
         # Prior history quarantined; only 5 days in new segment
         assert result.regime_days is not None
@@ -880,6 +931,7 @@ class TestIdentityChangeBlankKeys:
             d = (datetime(2026, 9, 21) + timedelta(days=i)).strftime("%Y-%m-%d")
             _insert_day(store, d, bw=bw)
         _insert_sample(store, "2026-09-26T10:00:00+00:00", pu=5)
+        _insert_complete_local_days(store, "2026-09-25", 1)
         result = compute_projection(store, _clock(year=2026, month=9, day=26, hour=12))
         assert result.regime_days is not None
         assert result.regime_days <= 5
@@ -895,6 +947,7 @@ class TestIdentityChangeBlankKeys:
             d = (datetime(2026, 9, 1) + timedelta(days=i)).strftime("%Y-%m-%d")
             _insert_day(store, d, bw=bw)
         _insert_sample(store, "2026-09-26T10:00:00+00:00", pu=5)
+        _insert_complete_local_days(store, "2026-09-25", 1)
         result = compute_projection(store, _clock(year=2026, month=9, day=26, hour=12))
         # All 25 days in same segment (equal blanks continue)
         assert result.regime_days is not None

tests/test_pruning.py

@@ -27,9 +27,14 @@ def store_conn(tmp_path: Path):
 
 
 def _insert_sample(conn, ts_iso, device="/dev/nvme0"):
+    conn.execute(
+        "INSERT OR IGNORE INTO controller_segments "
+        "(id, opened_at, identity_key) VALUES (1, '2026-01-01T00:00:00+00:00', 'test')"
+    )
     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)",
+        " bytes_written, bytes_read, percentage_used, segment_id, local_tz) "
+        "VALUES (?, ?, 0, 0, 0, 0, 0, 1, 'UTC')",
         (ts_iso, device),
     )
     conn.commit()
@@ -50,33 +55,30 @@ class TestPruneOldSamples:
         cursor = store_conn.execute("SELECT COUNT(*) FROM samples")
         assert cursor.fetchone()[0] == 1
 
-    def test_removes_old_samples(self, store_conn):
+    def test_keeps_old_samples_without_replacement_evidence(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
+        # Old samples stay until UTC and local-day evidence replace them.
         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
+        assert pruned == 0
 
         cursor = store_conn.execute("SELECT COUNT(*) FROM samples")
-        assert cursor.fetchone()[0] == 2
+        assert cursor.fetchone()[0] == 3
 
-    def test_removes_many_old_samples(self, store_conn):
+    def test_keeps_many_old_samples_without_replacement_evidence(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
+        assert pruned == 0
 
         cursor = store_conn.execute("SELECT COUNT(*) FROM samples")
-        assert cursor.fetchone()[0] == 14  # Days 1-14 kept
+        assert cursor.fetchone()[0] == 29
 
     def test_empty_store_no_error(self, store_conn):
         now = datetime(2026, 9, 15, 12, 0, 0, tzinfo=timezone.utc)
@@ -130,8 +132,8 @@ class TestPruneOldSamples:
         )
         assert cursor.fetchone()[0] == 1
 
-    def test_old_sample_with_derived_interval_removed(self, store_conn):
-        """Old samples with fully derived intervals are removed."""
+    def test_hour_rows_alone_do_not_replace_local_day_evidence(self, store_conn):
+        """An hour row alone cannot authorize source-sample deletion."""
         now = datetime(2026, 9, 30, 12, 0, 0, tzinfo=timezone.utc)
         
         # Old sample with derived interval
@@ -148,8 +150,8 @@ class TestPruneOldSamples:
         # Run pruning
         pruned = prune_old_samples(store_conn, now, retention_days=14)
         
-        # Old sample should be removed (interval is derived)
+        # Keep the source samples until local-day replacement evidence exists.
         cursor = store_conn.execute(
             "SELECT COUNT(*) FROM samples WHERE ts = '2026-09-10T10:00:00+00:00'"
         )
-        assert cursor.fetchone()[0] == 0
+        assert cursor.fetchone()[0] == 1

tests/test_repair.py

@@ -235,8 +235,8 @@ class TestBoundaryAnchorRetention:
         # 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."""
+    def test_hour_only_derivation_does_not_replace_local_day_evidence(self, store_conn):
+        """UTC hour evidence alone does not make a sample safe to prune."""
         now = datetime(2026, 9, 30, 12, 0, 0, tzinfo=timezone.utc)
         
         # Insert sample and fully derive its interval
@@ -247,8 +247,7 @@ class TestBoundaryAnchorRetention:
         _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)
+        assert 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."""
@@ -274,8 +273,8 @@ class TestBoundaryAnchorRetention:
         )
         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."""
+    def test_pruning_keeps_samples_without_local_day_replacement(self, store_conn):
+        """Pruning keeps samples when only the UTC-hour row exists."""
         now = datetime(2026, 9, 30, 12, 0, 0, tzinfo=timezone.utc)
         
         # Old sample with derived interval
@@ -289,11 +288,11 @@ class TestBoundaryAnchorRetention:
         # Run pruning
         pruned = prune_old_samples(store_conn, now, retention_days=14)
         
-        # Old sample should be removed (interval is derived)
+        # The source remains until local-day evidence is also durable.
         cursor = store_conn.execute(
             "SELECT COUNT(*) FROM samples WHERE ts = '2026-09-10T10:00:00+00:00'"
         )
-        assert cursor.fetchone()[0] == 0
+        assert cursor.fetchone()[0] == 1
 
 
 # ---------------------------------------------------------------------------

tests/test_status_composition.py

@@ -870,7 +870,7 @@ class TestRefreshTiming:
         _insert_segment(conn)
         _open_period(conn)
         now = _clock()
-        ts = (now - timedelta(minutes=10)).isoformat()
+        ts = (now - timedelta(minutes=4)).isoformat()
         _insert_sample(conn, ts)
         for i in range(20):
             d = (datetime(2026, 9, 10) + timedelta(days=i)).strftime("%Y-%m-%d")
@@ -878,27 +878,27 @@ class TestRefreshTiming:
 
         svc = {
             "boot_enabled": True, "timer_active": True,
-            "last_collect_ok": True, "last_collect_age_s": 600,
+            "last_collect_ok": True, "last_collect_age_s": 240,
             "last_collect_reason": None,
         }
 
-        # Sample is 10 min old (600s) → fresh (within 690s threshold)
+        # Sample is 4 min old (240s) → fresh (within 450s threshold)
         comp1 = compose_status(conn, svc, now, store_fault=None, newer_schema=None)
         assert comp1.freshness == "fresh"
         assert comp1.state == StatusState.MONITORING
 
-        # At now + 1 min → sample is 11 min old (660s) → still fresh
-        now2 = now + timedelta(minutes=1)
+        # At now + 3 min → sample is 7 min old (420s) → still fresh
+        now2 = now + timedelta(minutes=3)
         comp2 = compose_status(conn, svc, now2, store_fault=None, newer_schema=None)
         assert comp2.freshness == "fresh"
 
-        # At now + 2 min → sample is 12 min old (720s) → missed (past 690s)
-        now3 = now + timedelta(minutes=2)
+        # At now + 5 min → sample is 9 min old (540s) → missed (past 450s)
+        now3 = now + timedelta(minutes=5)
         comp3 = compose_status(conn, svc, now3, store_fault=None, newer_schema=None)
         assert comp3.freshness == "missed"
         assert comp3.state == StatusState.MONITORING
 
-        # At now + 49 hours → sample is 49h 10min old → stale
+        # At now + 49 hours → sample is 49h 4min old → stale
         now4 = now + timedelta(hours=49)
         comp4 = compose_status(conn, svc, now4, store_fault=None, newer_schema=None)
         assert comp4.freshness == "stale"

tests/test_status_read.py

@@ -67,7 +67,7 @@ async def test_cli_tui_acquisition_parity(tmp_path, kind, service):
                 assert not app.query_one("#main-grid").has_class("paused")
                 await pilot.resize_terminal(60, 18)
                 await pilot.pause()
-                assert phrase in str(app.query_one("#constrained-summary").render()).lower()
+                assert phrase in str(app.query_one("#live-render").render()).lower()
             for text in (cli, strip):
                 assert ("boot: enabled" if service == ACTIVE else "boot: disabled" if service == DISABLED else "boot: unknown") in text
                 assert ("timer: active" if service == ACTIVE else "timer: inactive" if service == DISABLED else "timer: unknown") in text

tests/test_themes.py

@@ -2,7 +2,7 @@
 
 Covers:
   - Three valid presets: Amber, Nord, High Contrast
-  - Amber is the default with amber graph role
+  - Chalktone is the default; Amber retains its amber graph role
   - Theme roles for graph rendering (allocated, unallocated, gap, zero, partial)
   - Status semantic colours/glyphs/text always win over theme
   - Global action reachability and focus contrast in every preset
@@ -29,13 +29,13 @@ from fenris.themes import (
 class TestThemeRegistry:
     """All three presets are registered with correct names."""
 
-    def test_three_themes_registered(self):
-        """Exactly three themes exist."""
-        assert len(THEMES) == 3
+    def test_four_themes_registered(self):
+        """All four presets are registered."""
+        assert len(THEMES) == 4
 
     def test_theme_names(self):
         """Theme names are amber, nord, high_contrast."""
-        assert THEME_NAMES == {"amber", "nord", "high_contrast"}
+        assert THEME_NAMES == {"chalktone", "amber", "nord", "high_contrast"}
 
     def test_get_theme_valid(self):
         """get_theme returns a Theme for each valid name."""
@@ -44,14 +44,14 @@ class TestThemeRegistry:
             theme = get_theme(name)
             assert isinstance(theme, Theme)
 
-    def test_get_theme_invalid_returns_amber(self):
+    def test_get_theme_invalid_returns_chalktone(self):
         """Unknown theme name returns the amber theme."""
         theme = get_theme("nonexistent")
-        assert theme.name == "fenris-amber"
+        assert theme.name == "fenris-chalktone"
 
 
 # ---------------------------------------------------------------------------
-# Amber theme tests (default, amber graph role)
+# Amber theme tests (amber graph role)
 # ---------------------------------------------------------------------------
 
 class TestAmberTheme:
@@ -179,7 +179,7 @@ class TestGraphColorRoles:
         assert amber["allocated"] != nord["allocated"] or amber["allocated"] != hc["allocated"]
 
     def test_zero_role_is_dim(self):
-        """Zero-usage bars use a dim/subtle colour in all themes."""
+        """Zero-usage markers use a dim/subtle colour in all themes."""
         for name in THEME_NAMES:
             colors = get_graph_colors(name)
             # Zero should be distinct from allocated

tests/test_tui.py

@@ -40,19 +40,13 @@ from fenris.status import (
 )
 from fenris.tui import (
     FenrisTuiApp,
-    DailyBarGraph,
+    HistoryGraph,
     _format_remaining,
     _query_drive_health,
     _query_daily_graph_data,
     _query_hourly_graph_data,
     _RANGE_OPTIONS,
     _RANGE_DEFAULT,
-    _BAR_HEIGHT,
-    _GLYPH_ALLOCATED,
-    _GLYPH_UNALLOCATED,
-    _GLYPH_GAP,
-    _GLYPH_ZERO,
-    _GLYPH_PARTIAL,
     _MIN_WIDTH,
     _MIN_HEIGHT,
 )
@@ -115,6 +109,34 @@ def _insert_sample(conn, ts, pu=5, device="/dev/nvme0n1"):
 
 def _open_period(conn, start="2026-09-01T00:00:00+00:00"):
     ensure_period_open(conn, datetime.fromisoformat(start))
+    conn.commit()
+
+
+def _insert_local_day(conn, local_date, tz_name="UTC", tz_offset="+00:00",
+                       utc_start=None, utc_end=None, bw=1024*1024*100,
+                       br=0, coverage=0.95, samples=24, complete=True):
+    """Insert a local_days row (issue #94 gate prerequisite)."""
+    if utc_start is None:
+        utc_start = local_date + "T00:00:00+00:00"
+    if utc_end is None:
+        dt = datetime.strptime(local_date, "%Y-%m-%d") + timedelta(days=1)
+        utc_end = dt.strftime("%Y-%m-%dT00:00:00+00:00")
+    conn.execute(
+        "INSERT INTO local_days "
+        "(local_date, tz_name, tz_offset, utc_start, utc_end, "
+        " bytes_written, bytes_read, coverage, sample_count, complete, activity_intervals) "
+        "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, 1)",
+        (local_date, tz_name, tz_offset, utc_start, utc_end,
+         bw, br, coverage, samples, complete),
+    )
+    conn.commit()
+
+
+def _insert_complete_local_days(conn, start_date, count, bw=1024*1024*100):
+    """Insert multiple complete local days to satisfy the issue #94 gate."""
+    for i in range(count):
+        d = (datetime.strptime(start_date, "%Y-%m-%d") + timedelta(days=i)).strftime("%Y-%m-%d")
+        _insert_local_day(conn, d, bw=bw)
 
 
 # ---------------------------------------------------------------------------
@@ -184,6 +206,7 @@ class TestStateMatrix:
             d = (datetime(2026, 9, 20) + 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")
+        _insert_complete_local_days(conn, "2026-09-29", 1)
         proj = compute_projection(conn, _clock())
         assert proj.confidence_state == ConfidenceState.LIMITED
         assert proj.headline_remaining_seconds is not None
@@ -199,6 +222,7 @@ class TestStateMatrix:
             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")
+        _insert_complete_local_days(conn, "2026-09-29", 1)
         proj = compute_projection(conn, _clock())
         assert proj.confidence_state == ConfidenceState.SUPPORTED
         assert proj.headline_remaining_seconds is not None
@@ -336,15 +360,15 @@ class TestDenseScreen:
         }):
             async with app.run_test():
                 strip = str(app.query_one("#service-strip").render()).lower()
-                rail = str(app.query_one("#quit-rail").render())
-                usage = app.query_one("#usage-history")
+                rail = str(app.query_one("#action-rail").render())
+                usage = app.query_one("#activity-panel")
                 service = app.query_one("#service-strip")
-                quit_rail = app.query_one("#quit-rail")
+                quit_rail = app.query_one("#action-rail")
                 assert "continuity" in strip
                 assert "monitoring: active in background · persists across reboots" in strip
-                assert "r resume — enable monitoring and future boots" in strip
+                assert "r Resume" in str(app.query_one("#action-rail").render())
                 assert "q quit" not in strip
-                assert rail == "q Quit TUI"
+                assert "q Quit TUI" in rail
                 assert usage.region.y < service.region.y < quit_rail.region.y
                 assert usage.region.bottom <= service.region.y
                 assert service.region.bottom <= quit_rail.region.y
@@ -376,13 +400,12 @@ class TestDenseScreen:
                 main_grid = app.query_one("#main-grid")
                 assert str(main_grid.styles.layout) == "<grid>"
                 assert main_grid.has_class("paused")
-                assert len(main_grid.styles.grid_rows) == 5
                 banner = str(paused_banner.render()).lower()
                 assert "monitoring: paused — deliberate disable" in banner
                 assert "paused time is excluded from your usage habit · resume: fenris monitor resume" in banner
-                assert paused_banner.region.height >= 5
-                assert paused_banner.region.y < app.query_one("#usage-history").region.y
-                assert app.query_one("#usage-history").region.bottom <= app.query_one(
+                assert paused_banner.region.height >= 2
+                assert paused_banner.region.y < app.query_one("#activity-panel").region.y
+                assert app.query_one("#activity-panel").region.bottom <= app.query_one(
                     "#service-strip"
                 ).region.y
                 screenshot = app.export_screenshot()
@@ -394,11 +417,6 @@ class TestDenseScreen:
                 assert "monitoring: does not start on next boot" in str(
                     app.query_one("#service-strip").render()
                 ).lower()
-                dashboard_scroll = app.query_one("#dashboard-scroll")
-                assert dashboard_scroll.max_scroll_y > 0
-                dashboard_scroll.focus()
-                await pilot.press("end")
-                assert dashboard_scroll.scroll_y == dashboard_scroll.max_scroll_y
                 footer_text = " ".join(
                     "".join(
                         ElementTree.fromstring(app.export_screenshot()).itertext()
@@ -461,23 +479,23 @@ class TestDenseScreen:
         async with app.run_test() as pilot:
             headline = str(app.query_one("#headline-band").render())
             # Identity now shows Fenris by Bongbetic (issue #79)
-            assert "Fenris by Bongbetic" in headline
-            assert auth_notice in headline
+            assert "Fenris by Bongbetic" in str(app.query_one("#identity").render())
+            assert auth_notice in str(app.query_one("#auth-notice").render())
             # Maker credit removed from service strip (issue #79)
             assert "by Bongbetic" not in str(app.query_one("#service-strip").render())
 
             await pilot.pause(0.25)
-            assert auth_notice not in str(app.query_one("#headline-band").render())
+            assert not app.query_one("#auth-notice").display
 
             await pilot.pause(0.25)
-            assert auth_notice not in str(app.query_one("#headline-band").render())
+            assert not app.query_one("#auth-notice").display
 
         fresh_app = FenrisTuiApp(
             store_path=tmp_path / "nonexistent.db",
             refresh_interval_s=0.2,
         )
         async with fresh_app.run_test():
-            assert auth_notice in str(fresh_app.query_one("#headline-band").render())
+            assert auth_notice in str(fresh_app.query_one("#auth-notice").render())
 
 
 # ---------------------------------------------------------------------------
@@ -571,7 +589,7 @@ class TestFirstRun:
             strip = str(app.query_one("#service-strip").render())
             assert "no observations yet" in headline.lower()
             assert "r resume — enable monitoring and future boots" in headline.lower()
-            assert "r resume — enable monitoring and future boots" in strip.lower()
+            assert "r resume" in str(app.query_one("#action-rail").render()).lower()
 
 
 # ---------------------------------------------------------------------------
@@ -771,12 +789,29 @@ class TestQueryDailyGraphData:
         assert result[0]["is_gap"] is True
         conn.close()
 
+    def test_window_is_consecutive_utc_days_with_explicit_gaps(self, tmp_path):
+        conn = init_store(tmp_path / "test.db")
+        _insert_day(conn, "2026-09-14", bw=500)
+        result = _query_daily_graph_data(
+            conn, datetime(2026, 9, 16, 12, tzinfo=timezone.utc),
+        )
+        assert len(result) == 90
+        assert result[-3]["day"] == "2026-09-14"
+        assert result[-2]["day"] == "2026-09-15"
+        assert result[-2]["is_gap"] is True
+        assert result[-1]["day"] == "2026-09-16"
+        assert result[-1]["is_partial"] is True
+        conn.close()
+
 
 class TestQueryHourlyGraphData:
     def test_empty_day(self, tmp_path):
         conn = init_store(tmp_path / "test.db")
-        result = _query_hourly_graph_data(conn, "2026-09-20")
-        assert result == []
+        result = _query_hourly_graph_data(
+            conn, "2026-09-20", datetime(2026, 9, 21, tzinfo=timezone.utc),
+        )
+        assert len(result) == 24
+        assert all(item["is_gap"] for item in result)
         conn.close()
 
     def test_with_hours(self, tmp_path):
@@ -795,22 +830,38 @@ class TestQueryHourlyGraphData:
     def test_hour_labels(self, tmp_path):
         conn = init_store(tmp_path / "test.db")
         _insert_hour(conn, "2026-09-20T12:00:00+00:00", bw=1000)
-        result = _query_hourly_graph_data(conn, "2026-09-20")
-        assert len(result) == 1
-        assert result[0]["local_label"] == "12"
+        result = _query_hourly_graph_data(
+            conn, "2026-09-20", datetime(2026, 9, 21, tzinfo=timezone.utc),
+        )
+        assert len(result) == 24
+        assert result[12]["local_label"] == "12"
+        assert result[12]["bytes_written"] == 1000
+        conn.close()
+
+    def test_current_hour_is_partial_and_future_hours_are_not_gaps(self, tmp_path):
+        conn = init_store(tmp_path / "test.db")
+        result = _query_hourly_graph_data(
+            conn, "2026-09-20",
+            datetime(2026, 9, 20, 14, 30, tzinfo=timezone.utc),
+        )
+        assert result[13]["is_gap"] is True
+        assert result[14]["is_partial"] is True
+        assert result[14]["is_gap"] is True
+        assert result[15]["is_future"] is True
+        assert result[15]["is_gap"] is False
         conn.close()
 
 
 # ---------------------------------------------------------------------------
-# DailyBarGraph widget unit tests (issue #75)
+# HistoryGraph widget unit tests (issue #75)
 # ---------------------------------------------------------------------------
 
-class TestDailyBarGraph:
+class TestHistoryGraph:
     def test_empty_data(self, tmp_path):
         """Empty data shows awaiting message."""
         app = FenrisTuiApp(store_path=tmp_path / "nonexistent.db")
         # We test the widget directly via the app's compose
-        graph = DailyBarGraph()
+        graph = HistoryGraph()
         # Simulate setting empty data
         from textual.app import App as TextualApp
         class _TestApp(TextualApp):
@@ -822,14 +873,14 @@ class TestDailyBarGraph:
 
     def test_range_default(self):
         """Default range is 14 days."""
-        graph = DailyBarGraph()
+        graph = HistoryGraph()
         assert graph.range_days == _RANGE_DEFAULT
         assert graph.selected_index == -1
         assert graph.view_mode == "daily"
 
     def test_trim_to_range(self):
         """Data is trimmed to the selected range."""
-        graph = DailyBarGraph()
+        graph = HistoryGraph()
         data = [{"day": "2026-09-%02d" % d, "total_bytes": d * 100}
                 for d in range(1, 31)]
         graph._all_day_data = data
@@ -840,7 +891,7 @@ class TestDailyBarGraph:
 
     def test_range_all_fits(self):
         """When data fits within range, all days are shown."""
-        graph = DailyBarGraph()
+        graph = HistoryGraph()
         data = [{"day": "2026-09-%02d" % d, "total_bytes": d * 100}
                 for d in range(1, 8)]
         graph._all_day_data = data
@@ -848,13 +899,24 @@ class TestDailyBarGraph:
         graph._trim_to_range()
         assert len(graph._day_data) == 7
 
+    def test_scale_includes_allocated_and_unallocated_writes(self):
+        graph = HistoryGraph()
+        graph._all_day_data = [{
+            "day": "2026-09-16",
+            "total_bytes": 800,
+            "allocated_bytes": 500,
+            "unallocated_bytes": 300,
+        }]
+        graph._trim_to_range()
+        assert graph._max_bytes == 800
+
 
 # ---------------------------------------------------------------------------
 # Bar graph headless TUI tests (issue #75)
 # ---------------------------------------------------------------------------
 
 class TestBarGraphTUI:
-    """Headless tests for the interactive bar graph."""
+    """Headless tests for the interactive history plot."""
 
     @pytest.mark.asyncio
     async def test_graph_renders_with_data(self, tmp_path):
@@ -870,13 +932,21 @@ class TestBarGraphTUI:
 
         app = FenrisTuiApp(store_path=tmp_path / "test.db")
         async with app.run_test(size=(80, 24)) as pilot:
+            await pilot.press("v", "v")
             graph = app.query_one("#usage-history")
-            assert isinstance(graph, DailyBarGraph)
+            assert isinstance(graph, HistoryGraph)
             assert len(graph._day_data) > 0
             # Legend should be visible
             legend = str(app.query_one("#bar-legend").render())
-            assert "Alloc" in legend
+            assert "Unalloc" in legend
             assert "Zero" in legend
+            range_label = str(app.query_one("#bar-range").render())
+            assert "14 days" in range_label
+            assert "UTC" in range_label
+            plotted = str(app.query_one("#bar-render").render())
+            assert "Writes (" in legend
+            assert "UTC" in range_label
+            assert "─" in plotted
 
     @pytest.mark.asyncio
     async def test_arrow_selection(self, tmp_path):
@@ -892,25 +962,22 @@ class TestBarGraphTUI:
 
         app = FenrisTuiApp(store_path=tmp_path / "test.db")
         async with app.run_test(size=(80, 24)) as pilot:
+            await pilot.press("v", "v")
             graph = app.query_one("#usage-history")
             app.set_focus(graph)
             await pilot.pause()
             await pilot.pause()
 
-            # Right arrow selects first bar
-            await pilot.press("right")
-            await pilot.pause()
-            assert graph.selected_index == 0
-
-            # Right again moves to second
-            await pilot.press("right")
-            await pilot.pause()
-            assert graph.selected_index == 1
-
-            # Left moves back
+            # The newest day is selected by default; left moves backward.
+            initial = graph.selected_index
             await pilot.press("left")
             await pilot.pause()
-            assert graph.selected_index == 0
+            assert graph.selected_index == initial - 1
+
+            # Right returns to the newest day.
+            await pilot.press("right")
+            await pilot.pause()
+            assert graph.selected_index == initial
 
     @pytest.mark.asyncio
     async def test_range_switching(self, tmp_path):
@@ -926,6 +993,7 @@ class TestBarGraphTUI:
 
         app = FenrisTuiApp(store_path=tmp_path / "test.db")
         async with app.run_test(size=(80, 24)) as pilot:
+            await pilot.press("v", "v")
             graph = app.query_one("#usage-history")
             app.set_focus(graph)
             await pilot.pause()
@@ -941,17 +1009,17 @@ class TestBarGraphTUI:
             assert graph.range_days == 7
             assert len(graph._day_data) == 7
 
-            # Press 3 for 28-day range
+            # Press 3 for 30-day range
             await pilot.press("3")
             await pilot.pause()
-            assert graph.range_days == 28
-            assert len(graph._day_data) == 28
+            assert graph.range_days == 30
+            assert len(graph._day_data) == 30
 
-            # Press 4 for 90-day range (only 30 days available)
+            # Exact windows retain gap slots instead of compressing time.
             await pilot.press("4")
             await pilot.pause()
             assert graph.range_days == 90
-            assert len(graph._day_data) == 30
+            assert len(graph._day_data) == 90
 
     @pytest.mark.asyncio
     async def test_readout_updates_on_selection(self, tmp_path):
@@ -967,17 +1035,19 @@ class TestBarGraphTUI:
 
         app = FenrisTuiApp(store_path=tmp_path / "test.db")
         async with app.run_test(size=(80, 24)) as pilot:
+            await pilot.press("v", "v")
             graph = app.query_one("#usage-history")
             app.set_focus(graph)
             await pilot.pause()
             await pilot.pause()
 
-            # No selection initially
+            # Newest day is selected initially.
             readout = str(app.query_one("#bar-readout").render())
-            assert "select" in readout.lower()
+            assert "UTC" in readout
+            assert "GB" in readout
 
-            # Select first bar
-            await pilot.press("right")
+            # Moving left updates the selected-day readout.
+            await pilot.press("left")
             await pilot.pause()
             readout = str(app.query_one("#bar-readout").render())
             assert "2026-09" in readout
@@ -1002,15 +1072,14 @@ class TestBarGraphTUI:
 
         app = FenrisTuiApp(store_path=tmp_path / "test.db")
         async with app.run_test(size=(80, 24)) as pilot:
+            await pilot.press("v", "v")
             graph = app.query_one("#usage-history")
             app.set_focus(graph)
             await pilot.pause()
             await pilot.pause()
 
-            # Select a day
-            await pilot.press("right")
-            await pilot.pause()
-            assert graph.selected_index == 0
+            # The newest day is selected automatically.
+            assert graph.selected_index == len(graph._day_data) - 1
             assert graph.view_mode == "daily"
 
             # Enter drill-down
@@ -1020,6 +1089,14 @@ class TestBarGraphTUI:
             assert graph.drill_day is not None
             assert len(graph._hour_data) == 24
 
+            # Five-minute data refreshes retain the selected hour.
+            graph._hourly_selected = 12
+            selected_hour = graph._hour_data[12]["hour"]
+            app._refresh()
+            await pilot.pause()
+            assert graph.view_mode == "hourly"
+            assert graph._hour_data[graph._hourly_selected]["hour"] == selected_hour
+
             # Esc returns to daily
             await pilot.press("escape")
             await pilot.pause()
@@ -1031,8 +1108,9 @@ class TestBarGraphTUI:
         """Empty store shows awaiting message in graph."""
         app = FenrisTuiApp(store_path=tmp_path / "nonexistent.db")
         async with app.run_test(size=(80, 24)) as pilot:
+            await pilot.press("v", "v")
             graph = app.query_one("#usage-history")
-            assert isinstance(graph, DailyBarGraph)
+            assert isinstance(graph, HistoryGraph)
             render = str(app.query_one("#bar-render").render())
             assert "awaiting" in render.lower()
 
@@ -1041,8 +1119,9 @@ class TestBarGraphTUI:
         """Graph pane has a border title."""
         app = FenrisTuiApp(store_path=tmp_path / "nonexistent.db")
         async with app.run_test(size=(80, 24)) as pilot:
+            await pilot.press("v", "v")
             graph = app.query_one("#usage-history")
-            assert graph.border_title == "Usage history"
+            assert app.query_one("#activity-panel").border_title == "Drive activity"
 
     @pytest.mark.asyncio
     async def test_glyphs_in_legend(self, tmp_path):
@@ -1058,13 +1137,11 @@ class TestBarGraphTUI:
 
         app = FenrisTuiApp(store_path=tmp_path / "test.db")
         async with app.run_test(size=(80, 24)) as pilot:
+            await pilot.press("v", "v")
             await pilot.pause()
             legend = str(app.query_one("#bar-legend").render())
-            assert _GLYPH_ALLOCATED in legend
-            assert _GLYPH_UNALLOCATED in legend
-            assert _GLYPH_GAP in legend
-            assert _GLYPH_ZERO in legend
-            assert _GLYPH_PARTIAL in legend
+            for meaning in ("Writes", "Unalloc", "Gap", "Zero", "Partial"):
+                assert meaning in legend
 
 
 # ---------------------------------------------------------------------------
@@ -1089,6 +1166,7 @@ class TestConstrainedLayout:
 
         app = FenrisTuiApp(store_path=tmp_path / "test.db")
         async with app.run_test(size=(80, 24)) as pilot:
+            await pilot.press("v", "v")
             # All four regions should be visible
             assert app.query_one("#headline-band") is not None
             assert app.query_one("#usage-history") is not None
@@ -1097,8 +1175,8 @@ class TestConstrainedLayout:
             # Graph should not be in constrained mode
             assert not app._is_constrained_mode
             # Constrained summary should be hidden
-            summary = app.query_one("#constrained-summary")
-            assert str(summary.styles.display) == "none"
+            summary = app.query_one("#bar-render")
+            assert "Graph needs" not in str(summary.render())
 
     @pytest.mark.asyncio
     async def test_constrained_below_80_width(self, tmp_path):
@@ -1115,17 +1193,18 @@ class TestConstrainedLayout:
 
         app = FenrisTuiApp(store_path=tmp_path / "test.db")
         async with app.run_test(size=(79, 24)) as pilot:
+            await pilot.press("v", "v")
             # Should be in constrained mode
             assert app._is_constrained_mode
             # Main grid should have constrained class
             main_grid = app.query_one("#main-grid")
             assert main_grid.has_class("constrained")
             # Constrained summary should be visible
-            summary = app.query_one("#constrained-summary")
+            summary = app.query_one("#bar-render")
             summary_text = str(summary.render())
             assert "Graph needs ≥80×24" in summary_text
             assert "days" in summary_text
-            assert "GB total" in summary_text
+            assert "GB" in summary_text
 
     @pytest.mark.asyncio
     async def test_constrained_below_24_height(self, tmp_path):
@@ -1142,10 +1221,11 @@ class TestConstrainedLayout:
 
         app = FenrisTuiApp(store_path=tmp_path / "test.db")
         async with app.run_test(size=(80, 23)) as pilot:
+            await pilot.press("v", "v")
             # Should be in constrained mode
             assert app._is_constrained_mode
             # Constrained summary should be visible
-            summary = app.query_one("#constrained-summary")
+            summary = app.query_one("#bar-render")
             summary_text = str(summary.render())
             assert "Graph needs ≥80×24" in summary_text
 
@@ -1164,11 +1244,12 @@ class TestConstrainedLayout:
 
         app = FenrisTuiApp(store_path=tmp_path / "test.db")
         async with app.run_test(size=(79, 24)) as pilot:
+            await pilot.press("v", "v")
             # Start in constrained mode
             assert app._is_constrained_mode
             graph = app.query_one("#usage-history")
-            # Select a day while constrained
-            graph.selected_index = 5
+            # Select a day through the visible graph while constrained.
+            await pilot.press(*(["left"] * 8))
 
             # Resize to normal — pilot.resize_terminal changes terminal size
             await pilot.resize_terminal(80, 24)
@@ -1202,15 +1283,14 @@ class TestConstrainedLayout:
 
         app = FenrisTuiApp(store_path=tmp_path / "test.db")
         async with app.run_test(size=(80, 24)) as pilot:
+            await pilot.press("v", "v")
             # Start in normal mode
             assert not app._is_constrained_mode
             graph = app.query_one("#usage-history")
             # Focus and select a day
             app.set_focus(graph)
             await pilot.pause()
-            await pilot.press("right")
-            await pilot.pause()
-            assert graph.selected_index == 0
+            assert graph.selected_index == len(graph._day_data) - 1
 
             # Resize to constrained — pilot.resize_terminal changes terminal size
             await pilot.resize_terminal(79, 24)
@@ -1222,7 +1302,7 @@ class TestConstrainedLayout:
             # Should be in constrained mode
             assert app._is_constrained_mode
             # Constrained summary should show selected day context
-            summary = app.query_one("#constrained-summary")
+            summary = app.query_one("#bar-render")
             summary_text = str(summary.render())
             assert "Graph needs ≥80×24" in summary_text
             # Selected day context should survive
@@ -1233,8 +1313,9 @@ class TestConstrainedLayout:
         """Constrained summary shows awaiting message for empty store."""
         app = FenrisTuiApp(store_path=tmp_path / "nonexistent.db")
         async with app.run_test(size=(79, 24)) as pilot:
+            await pilot.press("v", "v")
             assert app._is_constrained_mode
-            summary = app.query_one("#constrained-summary")
+            summary = app.query_one("#bar-render")
             summary_text = str(summary.render())
             assert "Graph needs ≥80×24" in summary_text
             assert "awaiting" in summary_text.lower()
@@ -1254,24 +1335,25 @@ class TestConstrainedLayout:
 
         app = FenrisTuiApp(store_path=tmp_path / "test.db")
         async with app.run_test(size=(79, 24)) as pilot:
+            await pilot.press("v", "v")
             # All regions should exist
             assert app.query_one("#headline-band") is not None
             assert app.query_one("#drive-health") is not None
             assert app.query_one("#service-strip") is not None
-            assert app.query_one("#quit-rail") is not None
+            assert app.query_one("#action-rail") is not None
 
             # Headline should contain projection
             headline = str(app.query_one("#headline-band").render())
             assert "remaining" in headline.lower() or "projection" in headline.lower()
 
             # Service strip should have actions
-            strip = str(app.query_one("#service-strip").render())
+            strip = str(app.query_one("#action-rail").render())
             assert "p Pause" in strip
             assert "r Resume" in strip
-            assert "q quit" not in strip  # Quit is in quit-rail
+            assert "q Quit TUI" in strip
 
             # Quit rail should be visible
-            rail = str(app.query_one("#quit-rail").render())
+            rail = str(app.query_one("#action-rail").render())
             assert "Quit" in rail
 
     @pytest.mark.asyncio
@@ -1287,6 +1369,7 @@ class TestConstrainedLayout:
 
         app = FenrisTuiApp(store_path=tmp_path / "test.db")
         async with app.run_test(size=(79, 24)) as pilot:
+            await pilot.press("v", "v")
             strip = str(app.query_one("#service-strip").render())
             # Status should be visible even with long reasons
             assert "stale" in strip.lower() or "freshness" in strip.lower()
@@ -1306,6 +1389,7 @@ class TestConstrainedLayout:
 
         app = FenrisTuiApp(store_path=tmp_path / "test.db")
         async with app.run_test(size=(79, 24)) as pilot:
+            await pilot.press("v", "v")
             # Quit should still work
             await pilot.press("q")
             assert not app.is_running
@@ -1315,6 +1399,7 @@ class TestConstrainedLayout:
         """Theme and motion toggles work in constrained mode."""
         app = FenrisTuiApp(store_path=tmp_path / "nonexistent.db")
         async with app.run_test(size=(79, 24)) as pilot:
+            await pilot.press("v", "v")
             assert app._is_constrained_mode
             # Toggle theme
             await pilot.press("t")
@@ -1334,8 +1419,8 @@ class TestConstrainedLayout:
         assert _MIN_HEIGHT == 24
 
     def test_is_constrained_with_terminal_width(self, tmp_path):
-        """DailyBarGraph._is_constrained checks terminal width."""
-        graph = DailyBarGraph()
+        """HistoryGraph._is_constrained checks terminal width."""
+        graph = HistoryGraph()
         # Widget-level check (no terminal width)
         assert graph._is_constrained() is False
         # Terminal width below minimum

tests/test_tz_util.py

@@ -0,0 +1,26 @@
+"""Timezone detection tests."""
+import sys
+from pathlib import Path
+
+sys.path.insert(0, str(Path(__file__).parent.parent / "src"))
+
+from fenris import tz_util
+
+
+def test_relative_localtime_symlink_returns_zoneinfo_key(tmp_path, monkeypatch):
+    zoneinfo = tmp_path / "usr" / "share" / "zoneinfo" / "Asia" / "Kolkata"
+    zoneinfo.parent.mkdir(parents=True)
+    zoneinfo.write_bytes(b"zoneinfo")
+    localtime = tmp_path / "etc" / "localtime"
+    localtime.parent.mkdir()
+    localtime.symlink_to("../usr/share/zoneinfo/Asia/Kolkata")
+
+    real_path = tz_util.Path
+    monkeypatch.setattr(
+        tz_util,
+        "Path",
+        lambda path: localtime if path == "/etc/localtime" else real_path(path),
+    )
+    monkeypatch.delenv("TZ", raising=False)
+
+    assert tz_util.detect_system_tz() == "Asia/Kolkata"

units/fenris-collect.timer

@@ -4,7 +4,7 @@ Documentation=https://git.bongbetic.com/xavierk/Fenris
 
 [Timer]
 OnBootSec=2min
-OnUnitInactiveSec=5min
+OnUnitInactiveSec=3min
 AccuracySec=30s
 Persistent=no
 

units/runit/fenris-collect/run

@@ -9,7 +9,7 @@
 #
 # Guarantees (must match systemd timer semantics):
 #   - Initial 2-minute boot delay (sleep 120 before first collect)
-#   - Completion-relative 5-minute cadence (sleep 300 after collect)
+#   - Completion-relative 3-minute cadence (sleep 180 after collect)
 #   - Bounded execution (timeout 90s on each collect)
 #   - No catch-up (fixed sleep interval, no Persistent=)
 #   - Serialized runs (runsv does not restart until exit)
@@ -20,7 +20,7 @@ set -eu
 
 COLLECT_TIMEOUT=90
 BOOT_DELAY=120
-CADENCE=300
+CADENCE=180
 LOCK_FILE=/var/lib/fenris/fenris-collect.lock
 
 # Ensure lock directory exists