♻️(backend) refactor backend recording state management

Instead of relying on the egress_started event—which fires when egress is
starting, not actually started—I now rely on egress_updated for more accurate
status updates. This is especially important for the active status, which
triggers after egress has truly joined the room. Using this avoids prematurely
stopping client-side listening to room.isRecording updates. A further
refactoring may remove reliance on room updates entirely.

The goal is to minimize handling metadata in the mediator class. egress_starting
is still used for simplicity, but egress_started could be considered in the
future.

Note: if the API to start egress hasn’t responded yet, the webhook may fail to
find the recording because it currently matches by worker ID. This is unstable.
A better approach would be to pass the database ID in the egress metadata and
recover the recording from it in the webhook.

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

@@ -1,7 +1,11 @@
 """Recording-related LiveKit Events Service"""
 
+# pylint: disable=no-member
+
 from logging import getLogger
 
+from livekit import api
+
 from core import models, utils
 
 logger = getLogger(__name__)
@@ -14,6 +18,27 @@ class RecordingEventsError(Exception):
 class RecordingEventsService:
     """Handles recording-related Livekit webhook events."""
 
+    @staticmethod
+    def handle_update(recording, egress_status):
+        """Handle egress status updates and sync recording state to room metadata."""
+
+        room_name = str(recording.room.id)
+
+        status_mapping = {
+            api.EgressStatus.EGRESS_ACTIVE: "started",
+            api.EgressStatus.EGRESS_ENDING: "saving",
+            api.EgressStatus.EGRESS_ABORTED: "aborted",
+        }
+
+        recording_status = status_mapping.get(egress_status)
+        if recording_status:
+            try:
+                utils.update_room_metadata(
+                    room_name, {"recording_status": recording_status}
+                )
+            except utils.MetadataUpdateException as e:
+                logger.exception("Failed to update room's metadata: %s", e)
+
     @staticmethod
     def handle_limit_reached(recording):
         """Stop recording and notify participants when limit is reached."""