feat(protocol): 添加传输状态事件管理协议会话状态

添加了新的 proto_transport_state_event 事件类型来跟踪协议传输连接状态，
包括链接断开和就绪状态。为 BLE NUS 和 USB CDC 模块实现了状态机管理，
替换原有的简单布尔标志，提供更精确的连接状态跟踪。

- 添加 proto_transport_state_event 事件定义和实现
- 为 BLE NUS 模块引入业务状态机管理
- 为 USB CDC 模块引入业务状态机管理
- 实现协议模块中的会话状态管理
- 移除 protocol_module_reset_transport_state 函数
- 更新 CMakeLists.txt 包含新事件源文件

inc/events/proto_transport_state_event.h

@@ -0,0 +1,36 @@
+#ifndef BLINKY_PROTO_TRANSPORT_STATE_EVENT_H_
+#define BLINKY_PROTO_TRANSPORT_STATE_EVENT_H_
+
+#include <app_event_manager.h>
+#include <app_event_manager_profiler_tracer.h>
+
+#include "proto_common.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct proto_transport_state_event {
+	struct app_event_header header;
+	enum proto_transport transport;
+	enum proto_transport_link_state state;
+};
+
+APP_EVENT_TYPE_DECLARE(proto_transport_state_event);
+
+static inline void submit_proto_transport_state_event(
+	enum proto_transport transport, enum proto_transport_link_state state)
+{
+	struct proto_transport_state_event *event =
+		new_proto_transport_state_event();
+
+	event->transport = transport;
+	event->state = state;
+	APP_EVENT_SUBMIT(event);
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* BLINKY_PROTO_TRANSPORT_STATE_EVENT_H_ */