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

Dockerfile

@@ -11,4 +11,6 @@ FROM nginx:alpine
 COPY --from=build /app/dist /usr/share/nginx/html
 COPY nginx.conf /etc/nginx/conf.d/default.conf
 EXPOSE 80
+HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
+  CMD wget -qO /dev/null http://localhost:80/ || exit 1
 CMD ["nginx", "-g", "daemon off;"]