feat(web-admin): wire list export on system user page

Pilot filtered and selected Excel export via ListExportDropdown.

Co-authored-by: Cursor <cursoragent@cursor.com>

web-admin/src/api/admin.ts

@@ -115,6 +115,15 @@ export function fetchUserList(params?: {
   })
 }
 
+/** Excel 导出用户 */
+export function fetchExportUsers(data: Record<string, any>) {
+  return request.post({
+    url: '/web/admin/users/export',
+    data,
+    responseType: 'blob',
+  })
+}
+
 export function fetchUserDetail(id: string) {
   return request.get<Api.User.UserItem>({
     url: `/web/admin/users/${id}`