fix: 公积金账户下拉只显示基本公积金，补充公积金下拉只显示补充

添加员工表单中：
- 公积金账户下拉：只显示 accountType !== 'SUPPLEMENTARY' 的基本公积金账户
- 补充公积金下拉：只显示 accountType === 'SUPPLEMENTARY' 的补充公积金账户

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

frontend/src/pages/roster/modals.tsx

@@ -760,6 +760,8 @@ export function AddEmployeeModal({ onClose, onSubmit, loading, error }: {
   })
   // 补充公积金账户（accountType=SUPPLEMENTARY）
   const supplementaryHousingAccounts = allHousingAccounts.filter((a: any) => a.accountType === 'SUPPLEMENTARY')
+  // 基本公积金账户（accountType 非 SUPPLEMENTARY）
+  const basicHousingAccounts = allHousingAccounts.filter((a: any) => a.accountType !== 'SUPPLEMENTARY')
 
   // 入职日期变更 → 同步合同开始日期 + 重算结束日期
   const handleHireDateChange = (hireDate: string) => {
@@ -1074,7 +1076,7 @@ export function AddEmployeeModal({ onClose, onSubmit, loading, error }: {
                 <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) => (
+                  {basicHousingAccounts.map((a: any) => (
                     <option key={a.id} value={a.id}>{a.name}（{a.city}）</option>
                   ))}
                 </Select>