fix(docker-compose): use overlay network for Swarm compatibility

Dokploy uses Docker Swarm - bridge networks don't work across
Swarm services. Changed internal network to overlay+attachable.

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

docker-compose.yml

@@ -37,6 +37,7 @@ volumes:
 
 networks:
   internal:
-    driver: bridge
+    driver: overlay
+    attachable: true
   dokploy-network:
     external: true