Secure QR check-in with operational controls

Check-in connects credentials to attendance records with cross-event denial, rate limiting, and audit logging.

• ✓Opaque QR credentials with hashed storage
• ✓Check-in scanning with concurrency controls
• ✓Cross-event credential denial
• ✓Refund-aware entitlement checks
• ✓Audit-friendly check-in logging
• ✓Operations workspace for live check-in monitoring
• ✓Manual token entry (camera scanner deferred)