fix: add Docker HEALTHCHECK for container health monitoring

- Add HEALTHCHECK instruction to Dockerfile (wget localhost:80, 30s interval)
- Add healthcheck config to docker-compose.yml
- Enables Docker/orchestrator health monitoring and auto-restart on failure

docker-compose.yml

@@ -6,3 +6,9 @@ services:
     ports:
       - "3000:80"
     restart: unless-stopped
+    healthcheck:
+      test: ["CMD", "wget", "-qO", "/dev/null", "http://localhost:80/"]
+      interval: 30s
+      timeout: 3s
+      start_period: 5s
+      retries: 3