Repository hygiene and smaller checker defects

[mairas]

From the review on PR #1: #1 (comment)

Smaller items, grouped because none is worth its own issue.

• No hard-coded hostname pre-commit check. docs/HOSTNAME_POLICY.md names a per-repository lefthook command running .github/scripts/check-hardcoded-hostnames.sh as the enforcement mechanism; this repo has the lefthook infrastructure but neither the command nor the script. 13 of the 22 workspace repos with a lefthook.yml carry it. Either add it or record the exemption in AGENTS.md.
• Nothing runs ruff format --check. pyproject.toml waives E501 as "handled by formatter", but CI and lefthook run ruff check only and ./run format rewrites rather than verifies. The sources are clean today, so adding the check costs nothing.
• ci.yml is hand-written where every other halos-org repo calls halos-org/shared-workflows. Producing no .deb does not opt a repo out — skip and skip-freeboard-panel are npm packages that call pr-checks.yml with skip-lintian: true, and version-bump-check already no-ops without a VERSION file. Either adopt it or record the deviation.
• The pre-commit hooks exit 0 with a warning when uv or ruff is missing, so a clean commit can mean nothing was checked.
• The gate covers locales configured with build: false. Parking a work-in-progress locale is the obvious escape hatch when a language falls behind; today it blocks every pull request instead of pausing one language. Decide deliberately and write it down either way.
• check-anchors reports a fragment link to a non-HTML asset as broken. resolve() appends index.html to any path without an .html suffix, so manual.pdf#page=12 — ordinary in hardware documentation — resolves to manual.pdf/index.html and fails. The documented remedy is --exclude, whose broad patterns produce the false green PR Package the documentation checkers and add a blocking translation gate #1 just closed. Return None for targets whose extension is present and is not .html.
• english_diff drops content lines beginning -- or ++ . The noise filter matches rendered diff lines by prefix, so a removed line whose text starts with -- becomes --- and is discarded as a file header. In the fixture a changed safety limit rendered as an addition with no corresponding removal. Drop headers by position, or match the anchored --- a/ forms.
• Page paths are interpolated unescaped into the comment. A fork PR can push a filename containing newlines and --> that terminates the table early, renders chosen prose in the bot's voice — including the "everything is current" sentence — and emits a second <!-- translation-status --> marker ahead of the real one, breaking find-or-update workflows.
• The README and AGENTS.md reference a v0.1.0 tag that does not exist yet. PR Package the documentation checkers and add a blocking translation gate #1 replaced the literal with a placeholder; cut the tag when the package is first pinned.