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/Contracts.tsx

@@ -2,8 +2,7 @@ import { useState, useRef } from 'react'
 import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query'
 import { Plus, Search, Paperclip, Trash2, X, FileText, Download, Eye } from 'lucide-react'
 import { toast } from 'sonner'
-import api from '../lib/api'
-import { rosterApi } from '../lib/api-services'
+import { rosterApi, employeeApi, attachmentApi } from '../lib/api-services'
 import Card from '../components/ui/Card'
 import Button from '../components/ui/Button'
 import { Input, Label, Select } from '../components/ui/Input'
@@ -49,13 +48,13 @@ export default function Contracts() {
       const params: any = { search, page, pageSize }
       if (filterDepartment) params.department = filterDepartment
       if (filterContractStatus) params.contractStatus = filterContractStatus
-      const res = await api.get('/roster', { params }) as any
+      const res = await rosterApi.list({ search, page, pageSize, department: filterDepartment || undefined, contractStatus: filterContractStatus || undefined } as any) as any
       return res
     },
   })
 
   const addMutation = useMutation({
-    mutationFn: (data: any) => api.post('/employees', data),
+    mutationFn: (data: any) => employeeApi.create(data),
     onSuccess: () => {
       queryClient.invalidateQueries({ queryKey: ['employees'] })
       queryClient.invalidateQueries({ queryKey: ['roster'] })
@@ -384,26 +383,24 @@ function EmployeeDetailDrawer({ employeeId, onClose }: { employeeId: string; onC
   const { data: employee } = useQuery<any>({
     queryKey: ['employee-detail', employeeId],
     queryFn: async () => {
-      const res = await api.get(`/employees/${employeeId}`) as any
-      return res.data
+      return await employeeApi.detail(employeeId)
     },
   })
 
   const { data: attachments } = useQuery<any[]>({
     queryKey: ['employee-attachments', employeeId],
     queryFn: async () => {
-      const res = await api.get(`/attachments/${employeeId}`) as any
-      return res.data
+      return await attachmentApi.list(employeeId)
     },
   })
 
   const addAttachmentMutation = useMutation({
-    mutationFn: (data: any) => api.post('/attachments', data),
+    mutationFn: (data: any) => attachmentApi.add(data),
     onSuccess: () => queryClient.invalidateQueries({ queryKey: ['employee-attachments', employeeId] }),
   })
 
   const deleteAttachmentMutation = useMutation({
-    mutationFn: (id: string) => api.delete(`/attachments/${id}`),
+    mutationFn: (id: string) => attachmentApi.remove(id),
     onSuccess: () => queryClient.invalidateQueries({ queryKey: ['employee-attachments', employeeId] }),
   })