Add event logging constants for assignment transfer events:
- AssignmentTransferRequest: Request initiated by user
- AssignmentTransferApprove: Leader approved transfer
- AssignmentTransferReject: Leader rejected transfer with reason
- AssignmentTransferAppeal: User appealed a rejection
- AssignmentTransferResolve: Final resolution by superuser
- AssignmentTransferComplete: Transfer completed successfully
- AssignmentTransferCancel: Transfer cancelled
Add assignment-transfers to GameEventLogs TARGET_COLLECTIONS
Add emitGameEvent support for all transfer event types in src/utils/event-log/emit.ts
This provides audit trail and notification support for the transfer workflow.