The hive convention is prose, not tracker tags, in code, but it was
enforced only at review time — three PRs this session needed
request-changes purely for stray tags in new comments.
Add scripts/check-issue-refs.sh: scans tracked source (rust, nix, js,
ts, css, html; markdown exempt) for a hash followed by an issue number
and emits a CI warning annotation per hit. The pattern is a hash, 2-5
digits, then a non-hex char or end-of-line, so it skips CSS hex
colours (letter-bearing or six/eight-digit) while catching tags; a
pure-numeric short hex is the only residual false positive (dodge with
the six-digit form).
Wire it into the CI workflow as a fast pre-check before nix flake
check. It runs in warn mode (exit 0) so it does not block while the
legacy backlog is cleaned up; the script takes a warn|deny arg so the
later flip to a hard gate is a one-word change, not a rewrite — the
same rollout shape as tightening a clippy lint.
094b317a83