🐛(backend) filter LiveKit events by room name regex to exclude Tchap

Add configurable room name regex filtering to exclude Tchap events from shared
LiveKit server webhooks, preventing backend spam from unrelated application
events while maintaining UUID-based room processing for visio.

Those unrelated application events are spamming the sentry.

Acknowledges this is a pragmatic solution trading proper namespace
prefixing for immediate spam reduction with minimal refactoring impact
leaving prefix-based approach for future improvement.

src/backend/core/services/livekit_events.py

@@ -2,6 +2,7 @@
 
 # pylint: disable=no-member
 
+import re
 import uuid
 from enum import Enum
 from logging import getLogger
@@ -92,6 +93,17 @@ class LiveKitEventsService:
         self.telephony_service = TelephonyService()
         self.recording_events = RecordingEventsService()
 
+        self._filter_regex = None
+        if settings.LIVEKIT_WEBHOOK_EVENTS_FILTER_REGEX:
+            try:
+                self._filter_regex = re.compile(
+                    settings.LIVEKIT_WEBHOOK_EVENTS_FILTER_REGEX
+                )
+            except re.error:
+                logger.exception(
+                    "Invalid LIVEKIT_WEBHOOK_EVENTS_FILTER_REGEX. Webhook filtering disabled."
+                )
+
     def receive(self, request):
         """Process webhook and route to appropriate handler."""
 
@@ -106,6 +118,10 @@ class LiveKitEventsService:
         except Exception as e:
             raise InvalidPayloadError("Invalid webhook payload") from e
 
+        if self._filter_regex and not self._filter_regex.search(data.room.name):
+            logger.info("Filtered webhook event for room '%s'", data.room.name)
+            return
+
         try:
             webhook_type = LiveKitWebhookEventType(data.event)
         except ValueError as e: