feat: add standalone Worker protocol SDK and ACK-loss regression

sdk/go/doc.go

@@ -1,4 +1,4 @@
-// Package orbit is the standalone Go SDK for Orbit. This foundation release
-// implements health calls; task, Worker and workflow APIs are planned next.
-// The SDK does not import server models, migrations or storage dependencies.
+// Package orbit 是 Orbit 的独立 Go SDK，提供健康、任务、队列与 Worker 底层协议。
+// WorkerConnection 不自动重连、续租或运行处理器；自动运行器与流程 SDK 仍在开发。
+// SDK 不导入服务端模型、迁移或数据库依赖。
 package orbit