task-55(账号/权限页面): 实现菜单新增表单

menu-manage-model.ts 增 createMenuForm/flattenMenuNodes/nextSiblingSort；menu-manage-api.ts
增 createMenu POST /api/admin/permission-menus(unwrap+解析落库节点)；MenusPage 新增菜单
Dialog(名称/标识/父菜单/路由/排序)校验后提交并刷新。8 用例全过，403 单测 + build 绿。

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

@@ -1,11 +1,22 @@
 <script setup lang="ts">
-import { onMounted, ref } from 'vue'
+import { computed, onMounted, reactive, ref } from 'vue'
 import { ElMessage } from 'element-plus'
-import { loadMenuManageTree } from './menu-manage-api'
-import type { MenuManageNode } from './menu-manage-model'
+import { createMenu, loadMenuManageTree } from './menu-manage-api'
+import {
+  createMenuForm,
+  flattenMenuNodes,
+  nextSiblingSort,
+  validateMenuManageForm,
+  type MenuManageForm,
+  type MenuManageNode,
+} from './menu-manage-model'
 
 const loading = ref(false)
 const rows = ref<MenuManageNode[]>([])
+const createVisible = ref(false)
+const saving = ref(false)
+const menuForm = reactive<MenuManageForm>(createMenuForm(null, 0))
+const parentOptions = computed(() => flattenMenuNodes(rows.value))
 
 async function loadMenus() {
   loading.value = true
@@ -18,6 +29,30 @@ async function loadMenus() {
   }
 }
 
+function openCreate() {
+  Object.assign(menuForm, createMenuForm(null, nextSiblingSort(rows.value, null)))
+  createVisible.value = true
+}
+
+async function saveCreate() {
+  const { valid, errors } = validateMenuManageForm(menuForm)
+  if (!valid) {
+    ElMessage.warning(Object.values(errors)[0])
+    return
+  }
+  saving.value = true
+  try {
+    await createMenu(menuForm)
+    ElMessage.success('创建成功')
+    createVisible.value = false
+    await loadMenus()
+  } catch (error) {
+    ElMessage.error(error instanceof Error ? error.message : '创建失败')
+  } finally {
+    saving.value = false
+  }
+}
+
 onMounted(loadMenus)
 </script>
 
@@ -28,7 +63,7 @@ onMounted(loadMenus)
         <h2>菜单管理</h2>
         <p>维护后台菜单树和页面路由。权限粒度仅到菜单/页面。</p>
       </div>
-      <el-button type="primary">新增菜单</el-button>
+      <el-button type="primary" @click="openCreate">新增菜单</el-button>
     </div>
     <el-card shadow="never">
       <el-table v-loading="loading" :data="rows" row-key="id" default-expand-all stripe>
@@ -43,5 +78,36 @@ onMounted(loadMenus)
         </el-table-column>
       </el-table>
     </el-card>
+
+    <el-dialog v-model="createVisible" title="新增菜单" width="520px">
+      <el-form label-width="96px">
+        <el-form-item label="菜单名称">
+          <el-input v-model="menuForm.name" placeholder="如：用户管理" />
+        </el-form-item>
+        <el-form-item label="权限标识">
+          <el-input v-model="menuForm.columnKey" placeholder="如：admin_users（唯一，稳定授权标识）" />
+        </el-form-item>
+        <el-form-item label="父菜单">
+          <el-select v-model="menuForm.parentId" clearable placeholder="作为根菜单" style="width: 100%">
+            <el-option
+              v-for="node in parentOptions"
+              :key="node.id"
+              :label="node.name"
+              :value="node.id"
+            />
+          </el-select>
+        </el-form-item>
+        <el-form-item label="路由">
+          <el-input v-model="menuForm.routePath" placeholder="如：/account/users 或 group-xxx" />
+        </el-form-item>
+        <el-form-item label="排序">
+          <el-input-number v-model="menuForm.sortOrder" :min="0" />
+        </el-form-item>
+      </el-form>
+      <template #footer>
+        <el-button @click="createVisible = false">取消</el-button>
+        <el-button type="primary" :loading="saving" @click="saveCreate">保存</el-button>
+      </template>
+    </el-dialog>
   </div>
 </template>