Adopt halos-docs-tools and the shared translation gate

[mairas]

The six checkers under scripts/ were copied into four documentation repositories. They now come from halos-org/docs-tools pinned at v0.1.0, and the workflow is the caller stanza for the shared reusable workflow in halos-org/shared-workflows.

The behaviour change is that the run now goes red where the version it replaces always stayed green: it fails when any translation is stale, missing, unstamped or orphaned. It does not yet block a merge — this repository has no branch protection and no ruleset, so the red check sits next to an enabled merge button. Making it required is a separate decision, and it carries a real cost: the gate judges the whole repository, so an English-only edit cannot go green without its translations. See the review synthesis on this PR. It still posts the report as a pull request comment first, so a red run always carries its own explanation.

Verified locally on this branch before pushing: mkdocs build --strict clean, check-anchors site reports all anchors resolving, translation-status --check exits 0 with fi at 15 current pages, and check-glossary fi and check-typography fi run against solutions/translation/finnish-glossary.md.

The caller deliberately carries no paths filter. A required check that never runs on a pull request touching none of the filtered paths leaves that pull request unmergeable forever.

Same change as hatlabs/halpi2#49 and hatlabs/halmet#24. Part of halos-org/halos#147.

[github-actions]

Translation status

fi — 15 current

Every translation of the pages in scope is current.

[mairas]

Code review — 7 personas, run against the identical change

This PR applies the same change as hatlabs/halpi2#49, so the review ran there. Full synthesis, all 23 findings: hatlabs/halpi2#49 (comment)

Everything that applied here is fixed and pushed in this branch's fix(docs) commit:

• The documented pre-flight could not reproduce the gate — the Verifying block ran translation-status, which always exits 0, while CI runs translation-status --check.
• deploy.yml holds pages: write and id-token: write and ran plain uv sync while the gate runs uv sync --locked. With a git dependency in the graph, a pin bumped without re-locking made the two disagree.
• Deleting the obsolete "register your locale in GLOSSARIES" instructions removed the only pointer to where registration now happens. The skill says so.
• The caller stanza now states what the called workflow enforces, since the failing command lives in a repository this one does not contain.
• Smaller: "All four, every time" over a block of five; the language-selector note naming two repositories and a count of three where four carry the block.

Two decisions are still open and they are not mine to make. Both are in the halpi2 synthesis under findings 1, 3 and 4: the gate judges the whole repository while work happens one page at a time, so an English-only edit cannot go green; and no branch protection or ruleset exists on main here, so a red check does not actually block a merge. Merging today leaves the check advisory, which is the option nobody chose.