feat(task1): restructure directories for turborepo monorepo

- Move backend/ to apps/server/ via git mv
- Move frontend/ to apps/admin/ via git mv
- Create packages/typescript-config/ with base, nestjs, and react-vite presets

apps/server/src/auth/decorators/permission.decorator.ts

@@ -0,0 +1,11 @@
+import { SetMetadata } from '@nestjs/common';
+
+export const PERMISSION_KEY = 'permissions';
+
+/**
+ * 声明接口所需权限。
+ * 多个参数之间为 OR 关系（用户拥有其中任一权限即可通过）。
+ * 不支持 AND 语义：多次调用装饰器会被全局 PermissionGuard 合并为扁平数组，效果等同于单次多参数调用。
+ */
+export const RequirePermission = (...permissions: string[]) =>
+  SetMetadata(PERMISSION_KEY, permissions);

apps/server/src/auth/decorators/public.decorator.ts

@@ -0,0 +1,4 @@
+import { SetMetadata } from '@nestjs/common';
+
+export const IS_PUBLIC_KEY = 'isPublic';
+export const Public = () => SetMetadata(IS_PUBLIC_KEY, true);