refactor: 端口改为内部映射，通过 Nginx 反向代理访问

- docker-compose.test.yml: API 和 MongoDB 端口改为 expose（仅容器内部可见）
- webhook-server.js: 端口改为 19001，绑定 127.0.0.1（仅本机访问）
- 新增 deploy/nginx-test.conf Nginx 反向代理配置
  - API: miniapp-api-test.dxz99wyr.cn → miniapp-api_test:3001
  - Webhook: miniapp-api-test-webhook.dxz99wyr.cn/webhook → 127.0.0.1:19001
- 更新 setup.sh 和 README.md 文档

deploy/webhook-server.js

@@ -3,7 +3,7 @@ const { exec } = require('child_process');
 const path = require('path');
 const crypto = require('crypto');
 
-const PORT = 9001;
+const PORT = 19001;
 const DEPLOY_DIR = '/opt/miniapp-api_test';
 const COMPOSE_FILE = 'docker-compose.test.yml';
 
@@ -98,8 +98,9 @@ const server = http.createServer(async (req, res) => {
   });
 });
 
-server.listen(PORT, '0.0.0.0', () => {
+server.listen(PORT, '127.0.0.1', () => {
   console.log(`Webhook 服务器已启动, 监听端口 ${PORT}`);
   console.log(`部署目录: ${DEPLOY_DIR}`);
-  console.log(`接收地址: http://your-server-ip:${PORT}/webhook`);
+  console.log(`接收地址: http://127.0.0.1:${PORT}/webhook`);
+  console.log(`Nginx 代理地址: http://your-server-ip/webhook`);
 });