✨(backend) add LiveKit egress_ended fallback for saving recordings

Recording lifecycle previously relied exclusively on the MinIO storage-hook
endpoint to transition from STOPPED to SAVED, which made the system dependent
on MinIO bucket notifications and lifecycle configuration. Introduce support
for LiveKit egress_ended webhook (EGRESS_COMPLETE, EGRESS_LIMIT_REACHED) as
 an alternative finalization mechanism for self-hosted deployments that do
 not use MinIO / S3 hooks.

Change behavior of existing configuation RECORDING_STORAGE_EVENT_ENABLE.
When the LiveKit mechanism is enabled (RECORDING_STORAGE_EVENT_ENABLE=False),
RecordingEventsService.handle_complete is triggered from
LiveKitEventsService._handle_egress_ended.

CHANGELOG.md

@@ -12,6 +12,7 @@ and this project adheres to
 
 - ✨(backend) add command to clean pending and deleted files
 - 🧱(helm) run clean files command as cronjob
+- ✨(backend) add fallback to save recordings without S3/MinIO webhooks
 
 ### Changed