优化: 大文件拆分+代码分割+按需加载+console清理+any类型替换

- Money.tsx (2260行→54行): 拆分为 money/ 子目录4个组件, React.lazy二级分割
- AIAssistant.tsx (2038行→63行): 拆分为 ai-assistant/ 子目录6个组件, React.lazy二级分割
- xlsx改为动态导入, OvertimeTab从345KB降至12.7KB
- api-services.ts: 请求参数 any→Record<string,unknown>
- 移除前端3处console.log残留
- 后端console替换为pino logger
- 前后端未使用import/变量清理
- Zod schema验证: termination/platform/special-status/work-process
- 新增 leave.routes.ts, acceptance-test.routes.ts
- UI组件: PageGuide, QueryError, Stepper

frontend/src/pages/AuditLog.tsx

@@ -1,6 +1,6 @@
 import { useState } from 'react'
 import { useQuery } from '@tanstack/react-query'
-import { ScrollText, Search, Filter } from 'lucide-react'
+import { ScrollText } from 'lucide-react'
 import { auditApi } from '../lib/api-services'
 import Card from '../components/ui/Card'
 import Button from '../components/ui/Button'