aca5d5f48a
- Introduced a vouching mechanism to manage PR authorization via a tracked user list and discussion-based management workflows. - Added automated PR gatekeeping workflows to close contributions from unvouched users and require specific labels for review. - Refactored PR event handling to support label-based review deferral and enforce authorization checks for labelers. - Added comprehensive test coverage for vouch-gate logic, including label activation and unauthorized access scenarios.