refactor: API口径统一 — 统计函数/员工列表/前端服务层

后端:
- /dashboard/compliance-score 改用 getHealthCheck，与体检诊断同口径
- 新增 /employees/list 端点（不分页，供各页面下拉选择）
- /employees/all-lite 增加 position 字段和 status 筛选参数
- getHealthCheck 未签合同改为查无合同记录的员工（非UNSIGNED类型）

前端:
- 新建 lib/api-services.ts 统一 API 服务层
- employeeApi/rosterApi/dashboardApi/attendanceApi 统一封装
- 6个页面迁移到统一 API 调用:
  - Attendance: employeeApi.list + rosterApi.departments
  - Termination: rosterApi.list + rosterApi.departments
  - Money: rosterApi.list + rosterApi.departments
  - PortalQRModal: employeeApi.list
  - AIAssistant: 3处 employeeApi.list 替代 /roster?pageSize=999
  - Contracts: rosterApi.departments
  - Dashboard: rosterApi.expiringContracts + dashboardApi.healthCheck/workforceStats

frontend/src/pages/Money.tsx

@@ -7,6 +7,7 @@ import { Calculator, AlertCircle, Info, Check, Upload, Layers, Settings as Setti
 import { Stepper, type Step } from '../components/ui/Stepper'
 import { InlineAlert } from '../components/ui/InlineAlert'
 import api from '../lib/api'
+import { rosterApi } from '../lib/api-services'
 import { useAuthStore } from '../store/authStore'
 import Card from '../components/ui/Card'
 import Button from '../components/ui/Button'
@@ -72,21 +73,14 @@ function CustomEmployeeSelector({ selectedIds, onChange }: { selectedIds: string
   const { data: employees } = useQuery<any>({
     queryKey: ['roster-for-batch', search, filterDept],
     queryFn: async () => {
-      const params: any = { pageSize: 999 }
-      if (search) params.search = search
-      if (filterDept) params.department = filterDept
-      params.status = 'ACTIVE'
-      const res = await api.get('/roster', { params }) as any
+      const res = await rosterApi.list({ pageSize: 999, search, department: filterDept, status: 'ACTIVE' })
       return res.data || []
     },
   })
 
   const { data: deptList } = useQuery<string[]>({
     queryKey: ['roster-departments'],
-    queryFn: async () => {
-      const res = await api.get('/roster/departments') as any
-      return res.data || []
-    },
+    queryFn: () => rosterApi.departments(),
   })
 
   const toggle = (id: string) => {