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/packages/effects/common-ui/src/components/index.ts

@@ -0,0 +1,34 @@
+export * from './api-component';
+export * from './captcha';
+export * from './col-page';
+export * from './count-to';
+export * from './ellipsis-text';
+export * from './icon-picker';
+export * from './json-viewer';
+export * from './loading';
+export * from './page';
+export * from './resize';
+export * from './tippy';
+export * from '@vben-core/form-ui';
+export * from '@vben-core/popup-ui';
+
+// 给文档用
+export {
+  VbenAvatar,
+  VbenButton,
+  VbenButtonGroup,
+  VbenCheckbox,
+  VbenCheckButtonGroup,
+  VbenCountToAnimator,
+  VbenFullScreen,
+  VbenInputPassword,
+  VbenLoading,
+  VbenLogo,
+  VbenPinInput,
+  VbenSelect,
+  VbenSpinner,
+  VbenTree,
+} from '@vben-core/shadcn-ui';
+
+export type { FlattenedItem } from '@vben-core/shadcn-ui';
+export { globalShareState } from '@vben-core/shared/global-state';