fix: 修复 Vercel serverless 模块路径解析问题

使用 path.resolve 动态解析 dist 目录路径，确保在 Vercel
serverless 环境中正确加载编译后的模块。

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

api/index.ts

@@ -4,6 +4,7 @@ import { ValidationPipe } from '@nestjs/common';
 import { DocumentBuilder, SwaggerModule } from '@nestjs/swagger';
 import express from 'express';
 import bodyParser from 'body-parser';
+import * as path from 'path';
 
 // 缓存 app 实例，避免每次冷启动都重新创建
 let cachedApp: any;
@@ -12,8 +13,13 @@ 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/app.module');
+    // 动态解析 dist 目录路径
+    // 在 Vercel 环境中，__dirname 是 /var/task/api
+    // dist 目录在 /var/task/dist
+    const distPath = path.resolve(__dirname, '..', 'dist', 'app.module');
+    console.log('Loading AppModule from:', distPath);
+
+    const { AppModule } = require(distPath);
 
     const app = await NestFactory.create(
       AppModule,
@@ -38,12 +44,25 @@ async function bootstrap() {
 
     // 尝试加载全局过滤器和拦截器
     try {
-      const {
-        HttpExceptionFilter,
-      } = require('../dist/common/filters/http-exception.filter');
-      const {
-        TransformInterceptor,
-      } = require('../dist/common/interceptors/transform.interceptor');
+      const httpExceptionFilterPath = path.resolve(
+        __dirname,
+        '..',
+        'dist',
+        'common',
+        'filters',
+        'http-exception.filter',
+      );
+      const transformInterceptorPath = path.resolve(
+        __dirname,
+        '..',
+        'dist',
+        'common',
+        'interceptors',
+        'transform.interceptor',
+      );
+
+      const { HttpExceptionFilter } = require(httpExceptionFilterPath);
+      const { TransformInterceptor } = require(transformInterceptorPath);
       app.useGlobalFilters(new HttpExceptionFilter());
       app.useGlobalInterceptors(new TransformInterceptor());
     } catch (error) {