fix: 批量删除用户改用 ConfirmDialog 替代浏览器原生 confirm()

- handleBatchAction 删除分支改为 setDeleteConfirm 弹 ConfirmDialog
- 确认后执行删除，取消则关闭弹框

frontend/src/pages/UsersPage.tsx

@@ -216,7 +216,20 @@ export default function UsersPage() {
   const handleBatchAction = async (action: string) => {
     const ids = Array.from(selectedIds);
     if (ids.length === 0) return;
-    if (action === 'delete' && !confirm(`确定删除选中的 ${ids.length} 个用户？此操作不可恢复。`)) return;
+    if (action === 'delete') {
+      setDeleteConfirm({
+        msg: `确定删除选中的 ${ids.length} 个用户？此操作不可恢复。`,
+        onConfirm: async () => {
+          try {
+            await Promise.all(ids.map(id => userApi.delete(id)));
+            toast('success', `已删除 ${ids.length} 个用户`);
+            setSelectedIds(new Set());
+            fetchUsers();
+          } catch { toast('error', '批量删除失败'); }
+        },
+      });
+      return;
+    }
     try {
       if (action === 'enable') {
         await Promise.all(ids.map(id => userApi.update(id, { is_active: true })));
@@ -224,9 +237,6 @@ export default function UsersPage() {
       } else if (action === 'disable') {
         await Promise.all(ids.map(id => userApi.update(id, { is_active: false })));
         toast('success', `已禁用 ${ids.length} 个用户`);
-      } else if (action === 'delete') {
-        await Promise.all(ids.map(id => userApi.delete(id)));
-        toast('success', `已删除 ${ids.length} 个用户`);
       }
       setSelectedIds(new Set());
       fetchUsers();