refactor(auth): 重构认证模块架构 - 将Gateway层组件从Business层分离

范围：src/gateway/auth/, src/business/auth/, src/app.module.ts
涉及文件：
- 新增：src/gateway/auth/ 目录及所有文件
- 移动：Controller、Guard、Decorator、DTO从business层移至gateway层
- 修改：src/business/auth/index.ts（移除Gateway层组件导出）
- 修改：src/app.module.ts（使用AuthGatewayModule替代AuthModule）

主要改进：
- 明确Gateway层和Business层的职责边界
- Controller、Guard、Decorator属于Gateway层职责
- Business层专注于业务逻辑和服务
- 符合分层架构设计原则

src/business/location_broadcast/controllers/location_broadcast.controller.ts

@@ -51,8 +51,8 @@ import {
   ApiBearerAuth,
   ApiBody,
 } from '@nestjs/swagger';
-import { JwtAuthGuard } from '../../auth/jwt_auth.guard';
-import { CurrentUser } from '../../auth/current_user.decorator';
+import { JwtAuthGuard } from '../../../gateway/auth/jwt_auth.guard';
+import { CurrentUser } from '../../../gateway/auth/current_user.decorator';
 import { JwtPayload } from '../../../core/login_core/login_core.service';
 
 // 导入业务服务