🐛 Enhanced Error Handling:
- Fixed 'User matching query does not exist' error in backup_cancel
- Handle case where backup_job.created_by is None (deleted user)
- Added error handling for audit logging to prevent cancellation failure
- Improved permission check to handle null created_by references
✅ Backup Cancellation Robustness:
- Now works even if the user who created the backup was deleted
- Audit logging failure won't prevent successful cancellation
- Better error isolation and reporting
The error occurred because the system tried to compare a null user reference
or failed during audit logging when user records were inconsistent.