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/components/ui/AIContextEntry.tsx

@@ -5,7 +5,7 @@
 import { useState, useRef, useEffect } from 'react'
 import { useMutation } from '@tanstack/react-query'
 import { Bot, Send, X, Sparkles } from 'lucide-react'
-import api from '../../lib/api'
+import { aiApi } from '../../lib/api-services'
 
 interface AIContextEntryProps {
   /** 当前页面上下文标识 */
@@ -39,7 +39,7 @@ export function AIContextEntry({ context, contextData, pageTitle }: AIContextEnt
   /** AI 问答 */
   const askMutation = useMutation({
     mutationFn: async (question: string) => {
-      const res = await api.post('/ai/context-ask', {
+      const res = await aiApi.contextAsk({
         context,
         contextData,
         pageTitle,

frontend/src/components/ui/CommandPalette.tsx

@@ -4,7 +4,7 @@
 import { useState, useEffect, useRef, useMemo } from 'react'
 import { useNavigate } from 'react-router-dom'
 import { Search, ArrowRight, Clock } from 'lucide-react'
-import api from '../../lib/api'
+import { searchApi } from '../../lib/api-services'
 
 /** 搜索结果类型 */
 interface SearchResult {
@@ -74,8 +74,8 @@ export function CommandPalette({ open, onClose }: CommandPaletteProps) {
     // 远程搜索员工
     const timer = setTimeout(async () => {
       try {
-        const res = await api.get('/search', { params: { q } }) as any
-        const remoteResults: SearchResult[] = (res.data?.employees || []).map((e: any) => ({
+        const res = await searchApi.search(q) as any
+        const remoteResults: SearchResult[] = (res?.employees || []).map((e: any) => ({
           type: 'employee' as const,
           id: e.id,
           title: e.name,