feat: 重构API协议，新增endpoint.zod.ts并删除api.zod.ts，更新测试文件

Author: hotlong

packages/spec/src/system/api.test.ts packages/spec/src/api/endpoint.test.tspackages/spec/src/system/api.test.ts renamed to packages/spec/src/api/endpoint.test.ts

@@ -5,7 +5,7 @@ import {
   ApiMappingSchema,
   HttpMethod,
   ApiEndpoint,
-} from './api.zod';
+} from '../system/api.zod';
 
 describe('HttpMethod', () => {
   it('should accept valid HTTP methods', () => {

packages/spec/src/system/api.zod.ts packages/spec/src/api/endpoint.zod.tspackages/spec/src/system/api.zod.ts renamed to packages/spec/src/api/endpoint.zod.ts

@@ -7,3 +7,4 @@
  */
 
 export * from './contract.zod';
+export * from './endpoint.zod';