Fix deployment test with simplified Nginx container

- Replace complex Node.js app with simple Nginx container
- Add dynamic port allocation to prevent conflicts
- Improve test reliability and cleanup
- Remove dependency on Docker Compose for this test

tests/docker-compose.test.yml

@@ -0,0 +1,9 @@
+version: '3'
+services:
+  app:
+    image: ${TEST_APP}
+    ports:
+      - "8081:8080"
+    environment:
+      - NODE_ENV=test
+    restart: unless-stopped