## Summary
- Refactor for readability + add tests
- Allow small agent-branch PRs to reach Tier 2 (< 50 prod lines, ≤ 3 files)
- Add cross-layer detection to keep multi-package changes at Tier 3+
- Raise Tier 2 ceiling from 100 → 150 production lines
- Exclude test and changeset files from line counts used for tier decisions
- Extract pure classification logic into .github/scripts/ for testability
- Gate classify job on tests passing in pr-triage.yml
- Only CI changes to main.yaml and release.yaml are tier 4
- Test changes in critical paths don't count toward tiering decisions
