feat: 账户关联根部门 + 员工新增自动带出账户

1. 账户管理：新建/编辑时可勾选关联 level=0 根部门（公司/分公司/子公司）
2. 后端新增 API：
   - PUT /social/accounts/:id/departments 批量关联根部门
   - GET /social/accounts/:id/departments 查询已关联部门
   - GET /social/department-account/:departmentId 按部门带出适用账户+标准
3. 部门更新 API 支持 socialAccountId/housingAccountId 字段
4. 员工新增表单：选定部门后自动带出社保公积金账户，可手动调整
5. 参保记录创建时写入 accountId

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

frontend/src/pages/roster/modals.tsx

@@ -1,7 +1,7 @@
 import { useState, useEffect } from "react"
 import { useQuery } from "@tanstack/react-query"
 import { toast } from "sonner"
-import { rosterApi, socialInsuranceApi, employeeApi } from '../../lib/api-services'
+import { rosterApi, socialInsuranceApi, employeeApi, socialAccountApi } from '../../lib/api-services'
 import api from '../../lib/api'
 import Button from "../../components/ui/Button"
 import { Input, Label, Select } from "../../components/ui/Input"
@@ -710,7 +710,7 @@ export function AddEmployeeModal({ onClose, onSubmit, loading, error }: {
       if (saved) return JSON.parse(saved)
     } catch {}
     return {
-      name: '', department: '', position: '', hireDate: todayStr, monthlySalary: '',
+      name: '', department: '', departmentId: '', position: '', hireDate: todayStr, monthlySalary: '',
       idCardNumber: '', gender: '男' as '男' | '女', femaleWorkerType: '' as '' | 'CADRE' | 'WORKER', phone: '',
       city: '北京', education: '',
       contractType: 'FIXED' as 'FIXED' | 'UNFIXED' | 'UNSIGNED',
@@ -735,6 +735,36 @@ export function AddEmployeeModal({ onClose, onSubmit, loading, error }: {
 
   const hireMonth = form.hireDate ? form.hireDate.slice(0, 7) : ''
 
+  // 选定部门后自动带出社保公积金账户
+  const [autoAccounts, setAutoAccounts] = useState<{ socialAccount: any; housingAccount: any; socialStandard: any; housingStandard: any } | null>(null)
+  const [manualSocialAccountId, setManualSocialAccountId] = useState<string>('')
+  const [manualHousingAccountId, setManualHousingAccountId] = useState<string>('')
+
+  // 部门变化时查询适用账户
+  useEffect(() => {
+    if (form.departmentId) {
+      socialAccountApi.departmentAccount(form.departmentId).then((res: any) => {
+        setAutoAccounts(res)
+        setManualSocialAccountId(res.socialAccount?.id || '')
+        setManualHousingAccountId(res.housingAccount?.id || '')
+      }).catch(() => {})
+    } else {
+      setAutoAccounts(null)
+    }
+  }, [form.departmentId])
+
+  // 加载所有账户列表（供手动调整）
+  const { data: allSocialAccounts = [] } = useQuery<any[]>({
+    queryKey: ['social-accounts', 'SOCIAL'],
+    queryFn: () => socialAccountApi.list('SOCIAL'),
+    enabled: !!form.departmentId,
+  })
+  const { data: allHousingAccounts = [] } = useQuery<any[]>({
+    queryKey: ['social-accounts', 'HOUSING'],
+    queryFn: () => socialAccountApi.list('HOUSING'),
+    enabled: !!form.departmentId,
+  })
+
   // 入职日期变更 → 同步合同开始日期 + 重算结束日期
   const handleHireDateChange = (hireDate: string) => {
     if (form.contractType === 'FIXED' && form.contractYears > 0 && hireDate) {
@@ -913,7 +943,7 @@ export function AddEmployeeModal({ onClose, onSubmit, loading, error }: {
       return
     }
     const data: any = {
-      name: form.name, department: form.department,
+      name: form.name, department: form.department, departmentId: form.departmentId || undefined,
       position: form.position || undefined,
       hireDate: new Date(form.hireDate).toISOString(),
       monthlySalary: form.monthlySalary, gender: form.gender,
@@ -925,6 +955,8 @@ export function AddEmployeeModal({ onClose, onSubmit, loading, error }: {
       socialInsStartMonth: form.socialInsStartMonth || undefined,
       housingFundBase: form.housingFundBase ? parseFloat(form.housingFundBase) : undefined,
       housingFundStartMonth: form.housingFundStartMonth || undefined,
+      socialAccountId: manualSocialAccountId || undefined,
+      housingAccountId: manualHousingAccountId || undefined,
     }
     if (form.contractType !== 'UNSIGNED' && form.startDate) {
       data.contract = {
@@ -964,7 +996,10 @@ export function AddEmployeeModal({ onClose, onSubmit, loading, error }: {
         {/* 基本信息 */}
         <div className="grid grid-cols-4 gap-4">
           <div><Label>姓名 *</Label><Input value={form.name} onChange={(e) => setForm({ ...form, name: e.target.value })} placeholder="员工姓名" /></div>
-          <div><Label>部门 *</Label><Select value={form.department} onChange={(e) => setForm({ ...form, department: e.target.value })}><option value="">请选择部门</option>{deptOptions.map(d => <option key={d.id} value={d.label}>{'　'.repeat(d.level)}{d.label}</option>)}</Select></div>
+          <div><Label>部门 *</Label><Select value={form.departmentId} onChange={(e) => {
+            const opt = deptOptions.find(d => d.id === e.target.value)
+            setForm({ ...form, departmentId: e.target.value, department: opt?.label || '' })
+          }}><option value="">请选择部门</option>{deptOptions.map(d => <option key={d.id} value={d.id}>{'　'.repeat(d.level)}{d.label}</option>)}</Select></div>
           <div><Label>职务/岗位</Label><Input value={form.position} onChange={(e) => setForm({ ...form, position: e.target.value })} placeholder="如：前端工程师" /></div>
           <div><Label>证件号码 *</Label><Input value={form.idCardNumber} onChange={(e) => handleIdCardChange(e.target.value)} placeholder="18位" maxLength={18} /></div>
           {idCardDuplicate?.exists && (
@@ -1037,9 +1072,42 @@ export function AddEmployeeModal({ onClose, onSubmit, loading, error }: {
             {isNoSocialContract ? (
               <span className="text-xs text-amber-600">劳务协议/实习协议人员不缴纳社保公积金</span>
             ) : (
-              <span className="text-xs text-gray-500">默认与月工资一致，可手动修改</span>
+              <span className="text-xs text-gray-500">选定部门后自动带出账户，可手动调整。缴费基数默认与月工资一致。</span>
             )}
           </div>
+          {/* 账户选择（选部门后自动带出，可手动调整） */}
+          {!isNoSocialContract && (
+            <div className="grid grid-cols-2 gap-4 mb-3">
+              <div>
+                <Label>社保账户</Label>
+                <Select value={manualSocialAccountId} onChange={(e) => setManualSocialAccountId(e.target.value)} disabled={!form.departmentId}>
+                  <option value="">{form.departmentId ? '未选择' : '请先选择部门'}</option>
+                  {allSocialAccounts.map((a: any) => (
+                    <option key={a.id} value={a.id}>{a.name}（{a.city}）</option>
+                  ))}
+                </Select>
+                {autoAccounts?.socialStandard && manualSocialAccountId === autoAccounts.socialAccount?.id && (
+                  <div className="text-xs text-gray-400 mt-1">
+                    当前标准：基数 {autoAccounts.socialStandard.baseMin}~{autoAccounts.socialStandard.baseMax}，养老 {autoAccounts.socialStandard.pensionOrg}%/{autoAccounts.socialStandard.pensionEmp}%
+                  </div>
+                )}
+              </div>
+              <div>
+                <Label>公积金账户</Label>
+                <Select value={manualHousingAccountId} onChange={(e) => setManualHousingAccountId(e.target.value)} disabled={!form.departmentId}>
+                  <option value="">{form.departmentId ? '未选择' : '请先选择部门'}</option>
+                  {allHousingAccounts.map((a: any) => (
+                    <option key={a.id} value={a.id}>{a.name}（{a.city}）</option>
+                  ))}
+                </Select>
+                {autoAccounts?.housingStandard && manualHousingAccountId === autoAccounts.housingAccount?.id && (
+                  <div className="text-xs text-gray-400 mt-1">
+                    当前标准：基数 {autoAccounts.housingStandard.baseMin}~{autoAccounts.housingStandard.baseMax}，公积金 {autoAccounts.housingStandard.housingOrg}%/{autoAccounts.housingStandard.housingEmp}%
+                  </div>
+                )}
+              </div>
+            </div>
+          )}
           <div className={`grid grid-cols-4 gap-4 ${isNoSocialContract ? 'opacity-50' : ''}`}>
             <div>
               <Label>社保缴费基数</Label>