chore(build): uv tooling, a Python 3.11 floor, and verified model downloads (epic #701, phases 2.5 & 5) (#713)

* chore(build): migrate justfile tooling to uv

All recipes now run through 'uv run' against .venv, with a shared
DEV_EXTRAS variable (dev + vad) because uv syncs the environment
exactly and would otherwise uninstall the dev tools between
recipes. 'deps' installs dev+vad; new 'deps-all' covers every
extra. 'build' switches to 'uv build'; 'version' uses --no-sync.

Bump [tool.uv] required-version to >=0.12,<0.13 for uv 0.12.x, and
raise the mypy python_version target to 3.12: mypy 1.19 in the lock
cannot target 3.9 and numpy 2.x stubs need a 3.12 target to parse
(mypy is not run in CI or pre-commit; this only affects 'just
typecheck').

* fix(tests): isolate test runs from real XDG state; fix Arch model-path crash

Local test runs failed en masse (185 failures) while CI stayed
green: tests picked up the developer's real ~/.local/share/vocalinux
models via the default XDG paths and switched IBus/keyboard code
paths through the desktop session env (XDG_CURRENT_DESKTOP/
XDG_SESSION_TYPE on GNOME/Wayland, issue #478 branches). conftest
now points XDG base dirs at a throwaway session-wide directory and
clears session variables at import time, mirroring a fresh CI
runner (paths like MODELS_DIR freeze at first import during
collection, so fixture-time isolation is too late).

Also guard the Arch branch of _get_system_model_paths(): it removed
/usr/local/share/vocalinux/models unconditionally and crashed with
ValueError on Arch hosts when a custom XDG_DATA_DIRS never added
that path. Add regression tests, and make the lock-file test assert
the actual $XDG_DATA_HOME/vocalinux contract instead of the
hardcoded ~/.local/share default.

* fix(tests): keep the IBus engine double a plain class

Python 3.14's unittest.mock re-instantiates a user subclass when it builds
child mocks (klass(name=...)). VocalinuxEngine inherits from whatever
IBus.Engine resolves to, and the test module bound that to the MagicMock
class itself, so every engine instantiation raised

    TypeError: VocalinuxEngine.__init__() got an unexpected keyword argument 'name'

on 3.14 while passing on 3.13. Replace it with a plain stand-in class that
still hands out per-instance MagicMocks for the IBus API surface the engine
touches.

The same pattern remains in test_ibus_engine.py, test_ibus_engine_utils.py,
test_ibus_active_engine_guard.py and test_ibus_xkb_wayland.py; those never
instantiate the engine, so they are unaffected for now.

* fix(install): build the venv from the system Python

install.sh looked up a bare `python3` from PATH. Started from an activated
virtualenv — a shell left in uv's .venv after `just deps` — it built venv/
from that interpreter, where distro PyGObject is invisible even with
--system-site-packages, and the run aborted with

    Distro PyGObject (python3-gi / python3-gobject) is not importable in the venv.

A mismatched venv/ then survived every retry, because the installer reuses
whatever venv it finds.

- drop an inherited VIRTUAL_ENV (and its bin from PATH) before any
  interpreter lookup
- select the interpreter explicitly: $SYSTEM_PYTHON (default
  /usr/bin/python3) or PATH python3, preferring one that can import gi,
  and create the venv with it instead of `python3`
- recreate venv/ when it was built by a different interpreter
- name the interpreter in the PyGObject guard's error

Documents the two environments (uv's .venv for tooling, venv/ for the
installed app) in CONTRIBUTING, the justfile header and AGENTS.md, and adds
the mismatch symptom to the INSTALL troubleshooting section.

* chore(python): raise the supported floor to 3.11

requires-python promised 3.9 while the CI matrix ran 3.9/3.10/3.11/3.13,
the classifiers advertised up to 3.14, mypy targeted 3.12 and install.sh
enforced 3.9 — five different answers to "which Python does this support".

Settle on 3.11 everywhere: pyproject (requires-python, classifiers, black
targets), install.sh's MIN_VERSION, check-system-deps.sh, the distro package
map, the CI matrix (now 3.11-3.14, matching the classifiers), the release and
nightly workflows, and the docs.

mypy now targets the floor instead of 3.12, so type checking covers what we
promise; numpy 2.x ships stubs in 3.12 syntax that a 3.11 target cannot
parse, so its imports are skipped. (mypy has 71 pre-existing errors either
way; no CI job gates on it.)

uv.lock and the requirements/* exports are regenerated — dropping 3.9/3.10
removes most of the version-conditional resolution branches.

tests/test_python_version_policy.py pins the invariant: install.sh's floor,
requires-python, the classifiers and the CI matrix must agree.

* ci: run lint and tests from uv.lock

The lock file and the hash-pinned exports were not enforced anywhere: CI
still built a venv by hand and installed unpinned `PyGObject` plus
`-e ".[dev,vad]"`, so the tool versions it checked against had nothing to do
with the ones `just lint` uses locally.

Both Python jobs now use astral-sh/setup-uv and run through `uv sync
--locked` / `uv run --locked`, which also fails the build when uv.lock drifts
from pyproject.toml.

Partially covers phase 5 of #701 (tests install from the lock, lock freshness
gate); trusted publishing, artifact checksums and action SHA pinning are
still open there.

* ci: lint from a dedicated dependency group

The lint job failed on this branch: `uv run --extra dev` syncs the whole
project, so it tried to build pyaudio from source on a runner that installs
no system dependencies.

    src/pyaudio/device_api.c:9:10: fatal error: portaudio.h: No such file or directory

Move black/isort/flake8 out of the `dev` extra into a `lint` dependency
group. CI runs `uv run --locked --only-group lint`, which installs the three
pure-Python tools and skips the project entirely — no portaudio or
girepository headers needed. `just deps` and DEV_EXTRAS request the group
alongside the dev extras, so the local environment still carries test and
lint tooling at once and `just lint` matches CI version for version.

pre-commit is unaffected: its hooks pin their own tool versions upstream.

* fix(install): never configure an engine the venv cannot import

vosk became an optional extra in #705, but the installer still writes
`"engine": "vosk"` into config.json on the whisper.cpp fallback path even
when installing the extra only produced a warning. config.json also survives
reinstalls — every writer guards on "file does not exist" — so an engine
picked by an earlier attempt outlives the venv that supported it. Either way
Vocalinux dies at startup:

    ModuleNotFoundError: No module named 'vosk'

- the fallback now writes the vosk config only when `import vosk` actually
  succeeds, and otherwise leaves the engine configuration alone
- a new verify_configured_engine() runs near the end of the install: if
  config.json selects vosk and the venv cannot import it, it says so and
  prints both fixes instead of leaving a broken install behind

* feat(models): verify every model download against a pinned digest

Pins a sha256/md5 per downloadable speech model in
src/vocalinux/utils/model_checksums.txt and verifies against it in both
install.sh and the runtime downloaders, before the file is moved into place.
Verification fails closed. Covers phase 2.5 of #701; see the PR for details.

* docs(agents): rebase AGENTS.md onto the #727 rewrite

* fix(install): hash models that are already on disk instead of trusting them

* refactor(models): one download path per engine, and fix Whisper's

* docs(install): drop distros that cannot meet the 3.11 floor

* docs: retire the distros and Python versions the 3.11 floor rules out

* fix(install): abort instead of warning when Python is below the floor

* fix(install): fall back to the system Python, not the one on PATH

* fix(install): match an existing venv by installation, not by X.Y

* fix(install): repair a config naming an engine the venv cannot import

* fix(models): pin VOSK by the sha256 of bytes we fetched, not upstream's md5

* fix(justfile): request the dev set in every recipe that syncs

* test(version): scan the docs and website trees for a stale Python floor

* docs: correct the stale model-checksum and distro claims

* fix(models): stamp the VOSK tree the app extracts, as the installer does

* fix(install): replace an unverified VOSK model only once its successor is ready

* docs(install): align the Fedora floor with the rest of the tree

* test(install): drop an f-string with no placeholders

* test(models): stub the downloader probe the VOSK installer test relies on

* docs: drop the long dashes from two model-checksum comments

* fix(install): gate on the interpreter, not on the distro release label

* fix(justfile): export the lint group into requirements/dev.txt

* fix(models): unpack the VOSK tree into staging and stamp it before the swap

* fix(whisper): adopt a checkpoint an earlier release stored under the catalog name

* docs(settings): state what a stray Whisper copy really means for deletion

* fix(models): hash a whisper.cpp model found on disk before it reaches ctypes

* docs(contributing): stop telling readers to uninstall their linters

* fix(install): stop warning off distros the project documents as supported

* docs(distros): file the supported derivatives under supported

web/src/app/faq/page.tsx

@@ -26,11 +26,11 @@ const faqCategories = [
       },
       {
         q: "Which Linux distributions are supported?",
-        a: "Vocalinux works on Ubuntu 22.04+, Fedora 39+, Arch Linux, Manjaro, Debian, and most other Linux distributions. See our install guides for distro-specific instructions.",
+        a: "Vocalinux works on Ubuntu 24.04+, Debian 12+, Fedora 39+, Arch Linux, Manjaro, and most other Linux distributions. See our install guides for distro-specific instructions.",
       },
       {
         q: "What are the system requirements?",
-        a: "You need Python 3.9+, a working microphone, and about 500MB of disk space. For GPU acceleration with whisper.cpp, you need Vulkan support (AMD, Intel, or NVIDIA).",
+        a: "You need Python 3.11+, a working microphone, and about 500MB of disk space. For GPU acceleration with whisper.cpp, you need Vulkan support (AMD, Intel, or NVIDIA).",
       },
     ],
   },

web/src/app/install/[distro]/page.tsx

@@ -33,18 +33,18 @@ const distroConfig: Record<DistroSlug, DistroConfig> = {
     name: "Ubuntu",
     title: "Install Voice Dictation on Ubuntu",
     description:
-      "Step-by-step Ubuntu voice dictation setup for offline speech-to-text with whisper.cpp and VOSK. Works on Ubuntu 22.04+, GNOME, KDE, X11, and Wayland.",
+      "Step-by-step Ubuntu voice dictation setup for offline speech-to-text with whisper.cpp and VOSK. Works on Ubuntu 24.04+, GNOME, KDE, X11, and Wayland.",
     intro:
       "This Ubuntu guide is tuned for practical desktop use: terminals, browsers, IDEs, office suites, and chat apps. Local engines keep audio on your machine. Remote API is optional.",
     prerequisites: [
-       "Ubuntu 22.04+ (or Ubuntu-based distro)",
-       "Python 3.9+",
+       "Ubuntu 24.04+ (or Ubuntu-based distro)",
+       "Python 3.11+",
       "Working microphone",
       "curl installed (sudo apt update && sudo apt install -y curl)",
     ],
     testedOn: [
       "Ubuntu 24.04 LTS (GNOME, Wayland)",
-      "Ubuntu 22.04 LTS (GNOME, X11)",
+      "Ubuntu 24.04 LTS (GNOME, X11)",
       "Kubuntu and Linux Mint derivatives",
     ],
     installCommand:
@@ -69,7 +69,7 @@ const distroConfig: Record<DistroSlug, DistroConfig> = {
       "Fedora is an excellent match for Vocalinux thanks to current Python stacks and up-to-date system libraries. This guide focuses on reliable setup and minimal friction.",
     prerequisites: [
        "Fedora Workstation 39+ (or Fedora-based distro)",
-       "Python 3.9+",
+       "Python 3.11+",
       "Working microphone",
       "curl installed (sudo dnf install -y curl)",
     ],
@@ -100,7 +100,7 @@ const distroConfig: Record<DistroSlug, DistroConfig> = {
       "Arch users usually care about control and performance. This guide keeps setup lean while preserving compatibility across rolling-release desktop environments.",
     prerequisites: [
        "Arch Linux / Manjaro / EndeavourOS",
-       "Python 3.9+",
+       "Python 3.11+",
       "Working microphone",
       "curl installed (sudo pacman -Sy --needed curl)",
     ],

web/src/app/install/page.tsx

@@ -17,7 +17,7 @@ const distroGuides = [
     name: "Ubuntu",
     href: "/install/ubuntu/",
     description:
-      "Install offline voice dictation on Ubuntu 22.04+ with GNOME, KDE, X11, or Wayland.",
+      "Install offline voice dictation on Ubuntu 24.04+ with GNOME, KDE, X11, or Wayland.",
     icon: Laptop,
   },
   {

web/src/app/page.tsx

@@ -815,7 +815,7 @@ export default function HomePage() {
                   question: "Which Linux distributions are supported?",
                   answer: (
                     <>
-                      Ubuntu 22.04+, Debian 11+, Fedora 39+, Arch, openSUSE
+                      Ubuntu 24.04+, Debian 12+, Fedora 39+, Arch, openSUSE
                       Tumbleweed, and most modern desktops on X11 or Wayland.{" "}
                       <Link href="/install/">Install guides</Link>.
                     </>

web/src/app/troubleshooting/page.tsx

@@ -23,7 +23,7 @@ const troubleshootingItems = [
     solutions: [
       "Ensure you ran the installer from the homepage or install guide",
       "Check if the virtual environment is activated: source ~/.local/share/vocalinux/venv/bin/activate",
-      "Verify Python version (3.9+ required): python3 --version",
+      "Verify Python version (3.11+ required): python3 --version",
       "Try reinstalling: ./uninstall.sh && ./install.sh",
     ],
   },
@@ -114,7 +114,7 @@ const troubleshootingItems = [
     solutions: [
       "Ensure you have internet connectivity for downloading dependencies",
       "Run with sufficient permissions (don't use sudo unless specifically needed)",
-      "Check your distribution is supported (Ubuntu 22.04+, Fedora 39+, Arch)",
+      "Check your distribution is supported (Ubuntu 24.04+, Debian 12+, Fedora 39+, Arch)",
       "Install system dependencies manually: sudo apt install python3-pip python3-gi python3-venv",
       "Check disk space: df -h",
     ],