fix(admin): 迁移 antd v6 弃用 API 并清理控制台警告

- Card bordered -> variant；Modal maskClosable -> mask.closable
- InputNumber addonBefore/After -> prefix/suffix；Statistic valueStyle -> styles.content
- Alert message -> title；Steps items.description -> items.content
- 移除考勤页未挂载 Form 上的 setFieldsValue，消除 useForm 警告

apps/admin/src/pages/Attendance/AttendanceAdminWorkspace.tsx

@@ -134,7 +134,7 @@ export const AttendanceAdminWorkspace: React.FC<{
         </Spin>
       </section>
 
-      <Card className="student-record-card" bordered={false} title="原始考勤明细">
+      <Card className="student-record-card" variant="borderless" title="原始考勤明细">
         <Table<AttendanceRecordItem>
           rowKey="id"
           columns={columns}

apps/admin/src/pages/Attendance/admin.tsx

@@ -1,4 +1,4 @@
-import React, { useCallback, useEffect, useMemo, useState } from 'react';
+import React, { useCallback, useMemo, useState } from 'react';
 import { useQuery, useQueryClient } from '@tanstack/react-query';
 import { useApiMutation } from '../../hooks/useApiMutation';
 import { validateResponse } from '../../utils/validate';
@@ -134,10 +134,6 @@ export const AdminAttendanceArchive: React.FC<{ canEdit: boolean }> = ({ canEdit
       ? scheduleId
       : undefined;
 
-  useEffect(() => {
-    periodForm.setFieldsValue({ periods });
-  }, [periods, periodForm]);
-
   const enabledPeriods = useMemo(
     () => periods.filter((period) => period.enabled).sort((a, b) => a.sortOrder - b.sortOrder),
     [periods],