fix: add Traefik service port label for frontend (port 3000)

Coolify generates router labels but not the service port label for
docker-compose services. Without this, Traefik gets 502 because it
doesn't know which port to forward traffic to.

docker-compose.yml

@@ -1,6 +1,8 @@
 services:
   frontend:
     build: ./frontend
+    labels:
+    - traefik.http.services.https-0-wvus7va5u0f9dmg27ggca7rl-frontend.loadbalancer.server.port=3000
     depends_on:
       backend:
         condition: service_healthy