✨(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.

src/backend/core/recording/event/parsers.py

@@ -58,7 +58,7 @@ class EventParser(Protocol):
     def parse(self, data: Dict) -> StorageEvent:
         """Extract storage event data from raw dictionary input."""
 
-    def validate(self, data: StorageEvent) -> None:
+    def validate(self, data: StorageEvent) -> str:
         """Verify storage event data meets all requirements."""
 
     def get_recording_id(self, data: Dict) -> str:

src/backend/core/recording/services/recording_events.py

@@ -8,6 +8,7 @@ from livekit import api
 
 from core import models, utils
 from core.models import Recording
+from core.recording.event.notification import notification_service
 
 logger = getLogger(__name__)
 
@@ -16,6 +17,10 @@ class RecordingEventsError(Exception):
     """Recording event handling fails."""
 
 
+class RecordingNotSavableError(Exception):
+    """Recording cannot be saved because it is either in an error state or has already been saved"""
+
+
 class RecordingEventsService:
     """Handles recording-related LiveKit webhook events."""
 
@@ -73,3 +78,23 @@ class RecordingEventsService:
                 f"Failed to notify participants in room '{recording.room.id}' about "
                 f"recording limit reached (recording_id={recording.id})"
             ) from e
+
+    @staticmethod
+    def handle_complete(recording: Recording):
+        """Notify external services and save recording."""
+
+        if not recording.is_savable():
+            raise RecordingNotSavableError
+
+        # Attempt to notify external services about the recording
+        # This is a non-blocking operation - failures are logged but don't interrupt the flow
+        notification_succeeded = notification_service.notify_external_services(
+            recording
+        )
+
+        recording.status = (
+            models.RecordingStatusChoices.NOTIFICATION_SUCCEEDED
+            if notification_succeeded
+            else models.RecordingStatusChoices.SAVED
+        )
+        recording.save()