task-43(账号/权限页面): 实现用户筛选条件状态

新增 users-filter.ts 页面局部状态机：keyword/createdByAdminId/page/pageSize
默认值、改条件重置第一页(withFilterReset)、翻页钳到>=1、空白关键字不算激活、
toUserListParams 映射查询参数；UsersPage 改用它，搜索按钮/回车重置页码。
筛选状态不入 Pinia。8 用例全过，307 单测 + build 绿。

admin-frontend-vue/src/pages/account/UsersPage.vue

@@ -4,16 +4,17 @@ import { ElMessage, ElMessageBox } from 'element-plus'
 import { http } from '@/api/http'
 import type { AdminUser } from '@/types/admin'
 import { fetchUserList } from '@/api/users'
+import { createUserFilterState, toUserListParams } from './users-filter'
 
 const loading = ref(false)
 const rows = ref<AdminUser[]>([])
 const total = ref(0)
-const form = reactive({ username: '', page: 1, pageSize: 15 })
+const filters = reactive(createUserFilterState())
 
 async function loadUsers() {
   loading.value = true
   try {
-    const page = await fetchUserList({ page: form.page, pageSize: form.pageSize, keyword: form.username || undefined })
+    const page = await fetchUserList(toUserListParams(filters))
     rows.value = page.items
     total.value = page.total
   } catch (error) {
@@ -23,6 +24,12 @@ async function loadUsers() {
   }
 }
 
+/** 提交新筛选条件：重置回第一页再查询。 */
+function search() {
+  filters.page = 1
+  void loadUsers()
+}
+
 async function removeUser(row: AdminUser) {
   try {
     await ElMessageBox.confirm(`确定删除用户“${row.username}”吗？`, '删除确认', { type: 'warning' })
@@ -35,7 +42,7 @@ async function removeUser(row: AdminUser) {
 }
 
 function changePage(page: number) {
-  form.page = page
+  filters.page = page
   void loadUsers()
 }
 
@@ -52,12 +59,12 @@ onMounted(loadUsers)
       <el-button type="primary">新建用户</el-button>
     </div>
     <el-card shadow="never">
-      <el-form inline @submit.prevent="loadUsers">
+      <el-form inline @submit.prevent="search">
         <el-form-item label="用户名">
-          <el-input v-model="form.username" clearable placeholder="模糊搜索" @keyup.enter="loadUsers" />
+          <el-input v-model="filters.keyword" clearable placeholder="模糊搜索" @keyup.enter="search" />
         </el-form-item>
         <el-form-item>
-          <el-button type="primary" @click="loadUsers">查询</el-button>
+          <el-button type="primary" @click="search">查询</el-button>
         </el-form-item>
       </el-form>
     </el-card>
@@ -79,8 +86,8 @@ onMounted(loadUsers)
         <el-pagination
           background
           layout="prev, pager, next"
-          :page-size="form.pageSize"
-          :current-page="form.page"
+          :page-size="filters.pageSize"
+          :current-page="filters.page"
           :total="total"
           @current-change="changePage"
         />