✨(backend) add dedicated service for LiveKit recording webhook events

Create new service to handle recording-related webhooks, starting with
limit reached events. Will expand to enhance UX by notifying backend
of other LiveKit events.

Doesn't fit cleanly with existing recording package - may need broader
redesign. Chose dedicated service over mixing responsibilities.

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

@@ -0,0 +1,49 @@
+"""Recording-related LiveKit Events Service"""
+
+from logging import getLogger
+
+from core import models, utils
+
+logger = getLogger(__name__)
+
+
+class RecordingEventsError(Exception):
+    """Recording event handling fails."""
+
+
+class RecordingEventsService:
+    """Handles recording-related Livekit webhook events."""
+
+    @staticmethod
+    def handle_limit_reached(recording):
+        """Stop recording and notify participants when limit is reached."""
+
+        recording.status = models.RecordingStatusChoices.STOPPED
+        recording.save()
+
+        notification_mapping = {
+            models.RecordingModeChoices.SCREEN_RECORDING: "screenRecordingLimitReached",
+            models.RecordingModeChoices.TRANSCRIPT: "transcriptionLimitReached",
+        }
+
+        notification_type = notification_mapping.get(recording.mode)
+        if not notification_type:
+            return
+
+        try:
+            utils.notify_participants(
+                room_name=str(recording.room.id),
+                notification_data={"type": notification_type},
+            )
+        except utils.NotificationError as e:
+            logger.exception(
+                "Failed to notify participants about recording limit reached: "
+                "room=%s, recording_id=%s, mode=%s",
+                recording.room.id,
+                recording.id,
+                recording.mode,
+            )
+            raise RecordingEventsError(
+                f"Failed to notify participants in room '{recording.room.id}' about "
+                f"recording limit reached (recording_id={recording.id})"
+            ) from e