Add Stop hook to verify CSS compiles before each…

Details

Project-shared Claude Code Stop hook (.claude/settings.json + a small
script under frontend/scripts/) that gates turn completion on a green
SCSS build whenever stylesheet files are touched:
- Runs only when there are uncommitted .scss/.css changes under
  frontend/jekyll (no-op otherwise, so it doesn't fire every turn).
- On a hit, runs `npm run css:check` (compiles every front-matter SCSS
  entry via frontend/scripts/check_scss.sh).
- On compile failure, emits a Stop-hook block decision feeding the
  exact dart-sass error back so it can be fixed before finishing.
- Respects stop_hook_active to avoid loops.
Pipe-tested all four branches (active=true skip, no-CSS-changes skip,
changed+compiles pass, changed+broken blocks with the failing partial's
line:col).
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018Z78wTEczDqpD4nqJWKRME

Files changed (2)