fix: 修复 Vercel serverless 运行时崩溃

关键修复：
- 使用 require() 而非 import() 动态加载编译后的模块
- 从 dist/src/ 路径加载模块（Vercel 构建后的路径）
- 移除 tsconfig 中对 api 目录的排除
- 配置 vercel.json 路由到 dist/api/index.js

技术说明：
- api/index.ts 会被编译到 dist/api/index.js
- 运行时从 dist/src/app.module 加载 NestJS 应用
- 使用 require 避免 TypeScript 编译时路径检查

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

api/index.ts

@@ -5,9 +5,6 @@ import { DocumentBuilder, SwaggerModule } from '@nestjs/swagger';
 import express from 'express';
 import bodyParser from 'body-parser';
 
-// 从源码导入，TypeScript 会编译到 dist
-import { AppModule } from '../src/app.module';
-
 // 缓存 app 实例，避免每次冷启动都重新创建
 let cachedApp: any;
 
@@ -15,6 +12,9 @@ async function bootstrap() {
   if (!cachedApp) {
     const expressApp = express();
 
+    // 使用 require 动态加载编译后的模块（避免 TypeScript 编译时检查）
+    const { AppModule } = require('../dist/src/app.module');
+
     const app = await NestFactory.create(
       AppModule,
       new ExpressAdapter(expressApp),
@@ -38,8 +38,8 @@ async function bootstrap() {
 
     // 尝试加载全局过滤器和拦截器
     try {
-      const { HttpExceptionFilter } = await import('../src/common/filters/http-exception.filter');
-      const { TransformInterceptor } = await import('../src/common/interceptors/transform.interceptor');
+      const { HttpExceptionFilter } = require('../dist/src/common/filters/http-exception.filter');
+      const { TransformInterceptor } = require('../dist/src/common/interceptors/transform.interceptor');
       app.useGlobalFilters(new HttpExceptionFilter());
       app.useGlobalInterceptors(new TransformInterceptor());
     } catch (error) {

tsconfig.json

@@ -18,5 +18,5 @@
     "forceConsistentCasingInFileNames": false,
     "noFallthroughCasesInSwitch": false
   },
-  "exclude": ["node_modules", "dist", "api"]
+  "exclude": ["node_modules", "dist"]
 }

vercel.json

@@ -1,3 +1,15 @@
 {
-  "version": 2
+  "version": 2,
+  "builds": [
+    {
+      "src": "package.json",
+      "use": "@vercel/node"
+    }
+  ],
+  "routes": [
+    {
+      "src": "/(.*)",
+      "dest": "/dist/api/index.js"
+    }
+  ]
 }