feat: 配置 Vercel serverless 部署支持

- 更新 vercel.json 使用 serverless 函数入口
- 添加 api/index.ts 作为 Vercel serverless handler
- 添加 .env.vercel 环境变量配置模板
- 支持 Swagger 文档在 serverless 环境运行

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.env.vercel

@@ -0,0 +1,21 @@
+# 数据库配置（需要在 Vercel Dashboard 中配置）
+SERVER_HOST=your-mysql-host
+SERVER_USER=your-mysql-user
+PASSWORD=your-mysql-password
+DATABASE=auth_db
+
+# JWT 配置
+JWT_SECRET=your-jwt-secret-key
+JWT_EXPIRES_IN=7d
+
+# OAuth 配置
+GITHUB_CLIENT_ID=your-github-client-id
+GITHUB_CLIENT_SECRET=your-github-client-secret
+GITHUB_CALLBACK_URL=https://tradingadvbackend.vercel.app/auth/github/callback
+
+LARK_APP_ID=your-lark-app-id
+LARK_APP_SECRET=your-lark-app-secret
+LARK_CALLBACK_URL=https://tradingadvbackend.vercel.app/auth/lark/callback
+
+# 前端回调地址
+FRONTEND_URL=https://tda.lcdd.net

api/index.ts

@@ -0,0 +1,63 @@
+import { NestFactory } from '@nestjs/core';
+import { AppModule } from '../src/app.module';
+import { HttpExceptionFilter } from '../src/common/filters/http-exception.filter';
+import { TransformInterceptor } from '../src/common/interceptors/transform.interceptor';
+import { ValidationPipe } from '@nestjs/common';
+import { DocumentBuilder, SwaggerModule } from '@nestjs/swagger';
+import * as bodyParser from 'body-parser';
+
+let cachedApp;
+
+async function bootstrap() {
+  if (!cachedApp) {
+    const app = await NestFactory.create(AppModule);
+
+    app.enableCors({
+      origin: true,
+      credentials: true,
+      methods: ['GET', 'POST', 'PUT', 'DELETE', 'PATCH', 'OPTIONS'],
+      allowedHeaders: [
+        'Content-Type',
+        'Authorization',
+        'Accept',
+        'Origin',
+        'Referer',
+        'User-Agent',
+      ],
+    });
+
+    app.useGlobalFilters(new HttpExceptionFilter());
+    app.useGlobalInterceptors(new TransformInterceptor());
+    app.useGlobalPipes(
+      new ValidationPipe({
+        whitelist: true,
+        forbidNonWhitelisted: true,
+        transform: true,
+      }),
+    );
+
+    app.use(bodyParser.json({ limit: '50mb' }));
+    app.use(bodyParser.urlencoded({ limit: '50mb', extended: true }));
+
+    // Swagger 配置
+    const config = new DocumentBuilder()
+      .setTitle('我的应用 API')
+      .setDescription('这是我的应用程序的 API 文档')
+      .setVersion('1.0')
+      .addBearerAuth()
+      .build();
+    const document = SwaggerModule.createDocument(app, config);
+    SwaggerModule.setup('api', app, document);
+
+    await app.init();
+    cachedApp = app;
+  }
+
+  return cachedApp;
+}
+
+export default async (req, res) => {
+  const app = await bootstrap();
+  const server = app.getHttpAdapter().getInstance();
+  return server(req, res);
+};

vercel.json

@@ -2,14 +2,14 @@
   "version": 2,
   "builds": [
     {
-      "src": "dist/main.js",
+      "src": "api/index.ts",
       "use": "@vercel/node"
     }
   ],
   "routes": [
     {
       "src": "/(.*)",
-      "dest": "dist/main.js"
+      "dest": "api/index.ts"
     }
   ],
   "buildCommand": "npx nest build",