refactor: 全量迁移前端 API 调用到统一 api-services 服务层

- 新建 api-services-raw.ts 导出原始 axios 方法供特殊端点使用
- 完成 api-services.ts 全领域覆盖（auth/employee/roster/dashboard/attendance/payroll/socialInsurance/commercialInsurance/termination/policies/evidence/audit/calendar/companyFiles/notifications/settings/ai/platform/portal/survey/search）
- 迁移所有 47+ 页面文件：pages/、pages/roster/、pages/portal/、pages/platform/、pages/auth/、pages/dashboard/、pages/compliance/
- 移除所有直接 import api from '../../lib/api' 引用
- 修复 Termination.tsx / WorkProcess.tsx 中 string|null 类型错误
- 修复 SocialInsurance.tsx 中 api-services-raw delete 导入名
- 修复 PlatformLogin.tsx 变量遮蔽问题
- tsc --noEmit 零错误，vite build 成功

frontend/src/pages/Compensation.tsx

@@ -1,7 +1,6 @@
 import { useState, useMemo } from 'react'
 import { useQuery } from '@tanstack/react-query'
 import { Calculator, Info, AlertCircle } from 'lucide-react'
-import api from '../lib/api'
 import { rosterApi } from '../lib/api-services'
 import Card from '../components/ui/Card'
 import Button from '../components/ui/Button'
@@ -24,7 +23,7 @@ function useEmployees() {
   return useQuery<EmployeeOption[]>({
     queryKey: ['roster-for-compensation'],
     queryFn: async () => {
-      const res = await api.get('/roster') as any
+      const res = await rosterApi.list({} as any) as any
       return res.data
     },
   })