fix(backend): Resolve duplicate /health route registration

- Move /health route into registerHealthRoutes function for backward compatibility
- Update index.ts to only call registerHealthRoutes once
- Now provides 3 endpoints: /health, /health/liveness, /health/readiness

Fixes: FastifyError Method 'GET' already declared for route '/health'

backend/src/index.ts

@@ -10,6 +10,8 @@ import knowledgeBaseRoutes from './legacy/routes/knowledgeBases.js';
 import { chatRoutes } from './legacy/routes/chatRoutes.js';
 import { batchRoutes } from './legacy/routes/batchRoutes.js';
 import reviewRoutes from './legacy/routes/reviewRoutes.js';
+import { registerHealthRoutes } from './common/health/index.js';
+import { logger } from './common/logging/index.js';
 
 
 // 全局处理BigInt序列化
@@ -52,24 +54,12 @@ await fastify.register(multipart, {
 console.log('✅ 文件上传插件已配置: 最大文件大小 10MB');
 
 
-// 健康检查路由
-fastify.get('/health', async () => {
-  // 检查数据库连接
-  let dbStatus = 'unknown';
-  try {
-    await prisma.$queryRaw`SELECT 1`;
-    dbStatus = 'connected';
-  } catch {
-    dbStatus = 'disconnected';
-  }
-
-  return {
-    status: 'ok',
-    database: dbStatus,
-    timestamp: new Date().toISOString(),
-    uptime: process.uptime(),
-  };
-});
+// ============================================
+// 【平台基础设施】健康检查路由
+// ============================================
+// 注册健康检查路由（/health, /health/liveness, /health/readiness）
+await registerHealthRoutes(fastify);
+logger.info('✅ 健康检查路由已注册');
 
 // API路由前缀
 fastify.get('/api/v1', async () => {