fix: add domverse network to backend service

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

flight-comparator/docker-compose.yml

@@ -11,7 +11,10 @@ services:
       - DATABASE_PATH=/app/data/cache.db
     volumes:
       - flight-radar-data:/app/data
-    # No ports exposed — only reachable by the frontend via the default compose network
+    networks:
+      - default
+      - domverse
+    # No ports exposed — only reachable by the frontend via nginx proxy
 
   frontend:
     build: