feat: art-design-pro 脚手架落地与品牌化（八页骨架/代理配置/权限菜单）

- 模板 art-design-pro（MIT）GitHub 直连克隆后裁剪落地 admin/：删除演示页面/示例数据/mock/未用组件，保留构建与依赖清单
- 品牌化：应用名/标题/侧栏与登录页 logo/浏览器 favicon 全部替换为 all-kefu 自有资源（static/kefu-small.png），中文界面
- 八页骨架：login / force-change-password / dashboard / tenants / conversations / config / stats / settings 占位页 + 6 组路由模块
- 权限菜单：meta.roles 前端过滤，super 全量，tenant 隐藏 租户管理/平台设置（角色值与后端一致）
- 开发代理：/api 直转 + /api/public 与 /static 携带租户 Host 改写（VITE_TENANT_PREVIEW_HOST），适配后端 TenantHostMiddleware
- 认证 API 为开发桩（角色调试开关），Task 3 对接真实登录

Co-Authored-By: Claude Code <noreply@anthropic.com>

admin/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2025 SuperManTT
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
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+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
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+
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+SOFTWARE.