Composite action that validates head branch and PR title against the
fritzlab naming standard (role/bug-id/kebab + [bug-id] titles).
Always exits 0 (warn-only) until the Bugs system is live.
- check.sh: validation logic (branch form, title form, bug-id cross-check)
- action.yaml: composite action wrapping check.sh
- tests/run: 20-case test matrix (valid/invalid/chore/mismatch/dfritz)
- .gitea/workflows/test.yaml: CI that runs the test suite
Closesfritzlab/agenthub#559
