refactor: 项目更名为 DiAL（统一拨测平台）

将 gateway-checker/Gateway Checker 统一替换为 dial-server/DiAL
- 包名、可执行文件名、API service 标识改为 dial-server
- UI 标题改为 DiAL，副标题改为统一拨测平台
- 同步更新测试断言、构建脚本、示例配置和文档

src/server/server.ts

@@ -23,7 +23,7 @@ export function startServer(options: StartServerOptions) {
     }),
   });
 
-  console.log(`Gateway Checker listening on ${server.url}`);
+  console.log(`DiAL listening on ${server.url}`);
 
   return server;
 }