TEST: Application workflow and matching cascade

[nora-weisser]

• Application created on submit → PENDING.
• PATCH /mentees/applications/{id}/approve (permission MENTEE_APPROVE) → PENDING → ADMIN_APPROVED; mentor can now see the application.
• PATCH /mentees/applications/{id}/reject (permission MENTEE_APPROVE, with reason) → PENDING → REJECTED or ADMIN_APPROVED → REJECTED.
• PATCH /mentors/applications/{id}/accept (permission MENTOR_APPL_WRITE) → ADMIN_APPROVED → MENTOR_ACCEPTED.
• PATCH /mentors/applications/{id}/decline (permission MENTOR_APPL_WRITE, with reason) → ADMIN_APPROVED → MENTOR_DECLINED. The service auto-forwards: it finds the next-priority application for the same mentee in the same cycle and moves it to the mentor's queue.
• When all priority applications are declined or rejected, the service inserts a PENDING_MANUAL_MATCH placeholder application for the mentee in that cycle.
• confirmMatch(applicationId) is the only path from MENTOR_ACCEPTED → MATCHED. It:
  • Verifies the application is MENTOR_ACCEPTED, else IllegalStateException.
  • Verifies the mentor has capacity, else MentorCapacityExceededException.
  • Verifies the mentee is not already matched in this cycle, else IllegalStateException.
  • Creates a MentorshipMatch row with MatchStatus.ACTIVE.
  • Updates the application to MATCHED.
  • Auto-rejects every other open application for that mentee in the same cycle with the reason "Mentee matched with another mentor".
  • Triggers a match-update notification.
• PATCH /mentees/applications/{id}/withdraw → DROPPED.