feat: 添加完整的前端管理系统 (VbenAdmin)

- 添加基于 VbenAdmin + Vue3 + Element Plus 的前端管理系统
- 包含完整的 UI 组件库和工具链
- 支持多应用架构 (web-ele, backend-mock, playground)
- 包含完整的开发规范和配置
- 修复 admin 目录的子模块问题，确保正确提交

admin/playground/src/api/core/auth.ts

@@ -0,0 +1,57 @@
+import { baseRequestClient, requestClient } from '#/api/request';
+
+export namespace AuthApi {
+  /** 登录接口参数 */
+  export interface LoginParams {
+    password?: string;
+    username?: string;
+  }
+
+  /** 登录接口返回值 */
+  export interface LoginResult {
+    accessToken: string;
+  }
+
+  export interface RefreshTokenResult {
+    data: string;
+    status: number;
+  }
+}
+
+/**
+ * 登录
+ */
+export async function loginApi(data: AuthApi.LoginParams) {
+  return requestClient.post<AuthApi.LoginResult>('/auth/login', data, {
+    withCredentials: true,
+  });
+}
+
+/**
+ * 刷新accessToken
+ */
+export async function refreshTokenApi() {
+  return baseRequestClient.post<AuthApi.RefreshTokenResult>(
+    '/auth/refresh',
+    null,
+    {
+      withCredentials: true,
+    },
+  );
+}
+
+/**
+ * 退出登录
+ */
+export async function logoutApi() {
+  return baseRequestClient.post('/auth/logout', null, {
+    withCredentials: true,
+  });
+}
+
+/**
+ * 获取用户权限码
+ */
+export async function getAccessCodesApi() {
+  return requestClient.get<string[]>('/auth/codes');
+}

admin/playground/src/api/core/index.ts

@@ -0,0 +1,3 @@
+export * from './auth';
+export * from './menu';
+export * from './user';

admin/playground/src/api/core/menu.ts

@@ -0,0 +1,10 @@
+import type { RouteRecordStringComponent } from '@vben/types';
+
+import { requestClient } from '#/api/request';
+
+/**
+ * 获取用户所有菜单
+ */
+export async function getAllMenusApi() {
+  return requestClient.get<RouteRecordStringComponent[]>('/menu/all');
+}

admin/playground/src/api/core/user.ts

@@ -0,0 +1,10 @@
+import type { UserInfo } from '@vben/types';
+
+import { requestClient } from '#/api/request';
+
+/**
+ * 获取用户信息
+ */
+export async function getUserInfoApi() {
+  return requestClient.get<UserInfo>('/user/info');
+}