## What changed
Introduce `ReviewRequest` in `codex-guardian-reviewer` to own contributor routing, cached approvals, synchronous fallback, and review cancellation. Keep action validation and session-specific preparation in the host.
Track the complete approval operation through parent shutdown, driving cancellation through reporting and reviewer cleanup before releasing it. Preserve fresh-review requirements and validate cached approvals before recording their outcome.
## Testing
Extend coverage for cancellation before routing and during cached approval, parent shutdown cleanup, and required fresh review overriding a cached allow result with matching assessment events and a denial warning.
GitOrigin-RevId: 8dcf26cc3660e91ef94e28e0bee7327ebe34ae6c
7f01a84eff