The new commit-time docs-mirror guard carries the forbidden branch-tip
docs URL as a scan constant, and the repo-wide link-drift smoke test
flagged the guard's own source for containing it, failing Script smoke
tests on main. Assemble the constant from parts so the runtime value is
unchanged while the literal never appears in the file. Both the drift
test and the mirror check pass locally at head.
Docs under frontend-modern/public/docs are byte-for-byte copies of repo
docs, but the only guard was a CI vitest the git hooks never run. On
2026-09-01 two commits (f4886c2dfb, f313882a7b) each edited a mirrored
doc without its copy, passed the hooks, and broke main's Frontend job.
Add scripts/check_docs_mirror.py with an index-blob --staged mode wired
into the pre-commit hook: a commit that stages either side of an
out-of-sync pair (or an orphan shipped copy) fails with the exact sync
command, while pre-existing drift from other commits only warns. The
worktree mode runs as a named step in the public-docs workflow, with
unit tests in scripts/tests picked up by the existing runner. The
docsLinks vitest stays as the CI backstop.
Build-time generation of public/docs was considered and rejected: the
shipped set is a curated subset (61 of 421 docs), so generation still
needs a hand-maintained manifest while adding build, dev-server, and
test-order coupling.
rcourtman