docs: run zensical in strict mode

[andrewcb22]

Summary

• Fix the migration guide links that pointed at outdated generated anchors.
• Run Zensical in strict mode in the docs workflow so broken links fail CI.
• Document the strict docs build command in the contributor checks.

Closes #81

Validation

• uv run zensical build --strict

[bagowix]

@andrewcb22 Thanks for the contribution!

There is one thing I’d like to address before merging: the Docs workflow currently runs only on pushes to main. This means broken links would be detected after the PR is merged, during the documentation deployment.

Could you please add a separate read-only docs check for pull requests, preferably as a dedicated job in ci.yml that runs once rather than as part of every Python matrix entry?
It should run:

uv sync --frozen
uv run zensical build --strict

Once that PR check is added, this should be good to merge.

[bagowix]

Thanks for the anchor fixes — those were correct. Since this had gone quiet for a few days while the strict-build errors kept resurfacing on main, I merged current main into this branch (a few unrelated commits had landed in the meantime) and added the requested PR-level docs job to ci.yml myself. Both uv run zensical build --strict and uv run zizmor .github/workflows/ pass clean on the result. Feel free to keep pushing to this branch as usual.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ All tests successful. No failed tests found.

📢 Thoughts on this report? Let us know!

[codspeed-hq]

Merging this PR will not alter performance

✅ 21 untouched benchmarks

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_{Comparing andrewcb22:docs/strict-zensical-links (09d4635) with main (ba96455)}