🐛(backend) resolve backchannel calls to LiveKit in docker-compose

Fix container networking issue where app-dev container couldn't resolve
localhost address when calling LiveKit API. Update configuration to use
proper container network addressing for backchannel communication between
services.

compose.yml

@@ -72,6 +72,8 @@ services:
         - nginx
         - livekit
         - createbuckets
+    extra_hosts:
+      - "127.0.0.1.nip.io:host-gateway"
   
   celery-dev:
     user: ${DOCKER_USER:-1000}