fix(contracts): 移除控制器路径中的重复 v1 前缀

全局前缀已是 api/v1，控制器路径应为 admin/contracts

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/services/admin-service/src/api/controllers/contract.controller.ts

@@ -41,7 +41,7 @@ interface BatchDownloadRequestDto {
  * 为管理后台提供合同查询和下载功能
  */
 @ApiTags('Admin - Contracts')
-@Controller('v1/admin/contracts')
+@Controller('admin/contracts')
 export class ContractController {
   private readonly logger = new Logger(ContractController.name);