Add host.docker.internal mapping for MinIO access

Add extra_hosts directive so the app container can reach
MinIO on the host machine via host.docker.internal.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

docker/docker-compose.yml

@@ -13,6 +13,8 @@ services:
     image: ${REGISTRY_URL}/mopc-app:latest
     container_name: mopc-app
     restart: unless-stopped
+    extra_hosts:
+      - "host.docker.internal:host-gateway"
     ports:
       - "127.0.0.1:7600:7600"
     env_file: