feat(proto): 添加设备通信协议v1修订版及统一帧格式

- 新增docs/device_communication_protocol_v1.md文档，定义V1修订版协议
- CDC和BLE GATT均改为直接传输业务消息，去掉外层协议封装
- BLE改为使用NUS(Nordic UART Service)替代原有GATT服务
- 统一键盘位图为29字节格式，FunctionKeyEvent改为上报全键盘位图
- 顶层消息增加msg_id和reply_to字段用于请求响应匹配
- Ack和Error合并为统一Response消息类型
- CDC和NUS均增加统一外层帧格式：magic(2) + len(1) + protobuf
- 添加Proto frame常量定义及长度验证逻辑
- 更新proto文件定义，包含DeviceMessage统一信封和ResponseCode枚举

- 重构hid_flowctrl_module.c中的上下文访问方式，统一使用ctx前缀

src/usb_cdc_module.c

@@ -28,8 +28,7 @@ LOG_MODULE_REGISTER(MODULE, LOG_LEVEL_INF);
 #define USB_CDC_RX_RING_BUF_SIZE 256
 #define USB_CDC_TX_RING_BUF_SIZE 256
 #define USB_CDC_RX_CHUNK_SIZE 32
-#define USB_CDC_PROTO_RX_BUF_SIZE 128
-#define USB_CDC_PROTO_RX_FLUSH_DELAY K_MSEC(3)
+#define USB_CDC_PROTO_RX_BUF_SIZE PROTO_MAX_FRAME_LEN
 #define USB_CDC_EXPECTED_BAUDRATE 115200U
 
 enum usb_cdc_business_state {
@@ -47,7 +46,6 @@ struct usb_cdc_ctx {
 	struct ring_buf rx_ringbuf;
 	struct ring_buf tx_ringbuf;
 	struct k_work rx_work;
-	struct k_work_delayable rx_flush_work;
 	uint8_t proto_rx_buf[USB_CDC_PROTO_RX_BUF_SIZE];
 	bool usb_active;
 	size_t proto_rx_len;
@@ -79,8 +77,6 @@ static struct usb_cdc_ctx ctx = {
 	.proto_rx_len = 0U,
 };
 
-#define proto_rx_buf ctx.proto_rx_buf
-
 static void validate_line_coding(void);
 
 static const char *usb_cdc_business_state_name(enum usb_cdc_business_state state)
@@ -137,7 +133,6 @@ static void disable_uart_io(void)
 	uart_irq_rx_disable(ctx.cdc_dev);
 	uart_irq_tx_disable(ctx.cdc_dev);
 	ctx.proto_rx_len = 0U;
-	k_work_cancel_delayable(&ctx.rx_flush_work);
 	reset_ring_buffers();
 }
 
@@ -280,6 +275,46 @@ static void validate_line_coding(void)
 #endif
 }
 
+static bool try_extract_frame(void)
+{
+	uint8_t *buf = ctx.proto_rx_buf;
+	size_t frame_len;
+	uint16_t magic;
+
+	if (ctx.proto_rx_len < PROTO_FRAME_HEADER_SIZE) {
+		return false;
+	}
+
+	magic = (uint16_t)buf[0] | ((uint16_t)buf[1] << 8);
+	if (magic != PROTO_FRAME_MAGIC) {
+		LOG_WRN("CDC invalid frame magic 0x%04x", magic);
+		memmove(buf, &buf[1], ctx.proto_rx_len - 1U);
+		ctx.proto_rx_len--;
+		return true;
+	}
+
+	if (buf[2] > PROTO_MAX_PAYLOAD_LEN) {
+		LOG_WRN("CDC invalid frame len:%u", buf[2]);
+		memmove(buf, &buf[1], ctx.proto_rx_len - 1U);
+		ctx.proto_rx_len--;
+		return true;
+	}
+
+	frame_len = PROTO_FRAME_HEADER_SIZE + buf[2];
+	if (ctx.proto_rx_len < frame_len) {
+		return false;
+	}
+
+	LOG_INF("CDC submit framed proto_rx len:%u", (unsigned int)frame_len);
+	(void)submit_proto_rx_event(PROTO_TRANSPORT_USB_CDC, buf, frame_len);
+
+	if (ctx.proto_rx_len > frame_len) {
+		memmove(buf, &buf[frame_len], ctx.proto_rx_len - frame_len);
+	}
+	ctx.proto_rx_len -= frame_len;
+	return true;
+}
+
 static void rx_work_handler(struct k_work *work)
 {
 	uint8_t buffer[USB_CDC_RX_CHUNK_SIZE];
@@ -290,47 +325,30 @@ static void rx_work_handler(struct k_work *work)
 		uint32_t len;
 		unsigned int key = irq_lock();
 
-			len = ring_buf_get(&ctx.rx_ringbuf, buffer, sizeof(buffer));
+		len = ring_buf_get(&ctx.rx_ringbuf, buffer, sizeof(buffer));
 		irq_unlock(key);
 
 		if (len == 0U) {
-			return;
+			break;
 		}
 
 		LOG_INF("CDC rx_work pulled %u bytes from RX ring (proto_rx_len:%u)",
 			(unsigned int)len, (unsigned int)ctx.proto_rx_len);
 
-		if ((ctx.proto_rx_len + len) > sizeof(proto_rx_buf)) {
-			LOG_WRN("Drop oversized CDC protobuf message len:%u",
+		if ((ctx.proto_rx_len + len) > sizeof(ctx.proto_rx_buf)) {
+			LOG_WRN("Drop oversized CDC framed data len:%u",
 				(uint32_t)(ctx.proto_rx_len + len));
 			ctx.proto_rx_len = 0U;
 		}
 
 		if (len > 0U) {
-			memcpy(&proto_rx_buf[ctx.proto_rx_len], buffer, len);
+			memcpy(&ctx.proto_rx_buf[ctx.proto_rx_len], buffer, len);
 			ctx.proto_rx_len += len;
-			k_work_reschedule(&ctx.rx_flush_work, USB_CDC_PROTO_RX_FLUSH_DELAY);
 		}
 	}
-}
 
-static void rx_flush_work_handler(struct k_work *work)
-{
-	ARG_UNUSED(work);
-
-	if ((transport_link_state_get() != PROTO_TRANSPORT_LINK_READY) ||
-	    (ctx.proto_rx_len == 0U)) {
-		LOG_INF("CDC rx_flush skipped: link=%s proto_rx_len:%u business:%s",
-			proto_link_state_name(transport_link_state_get()),
-			(unsigned int)ctx.proto_rx_len,
-			usb_cdc_business_state_name(ctx.business));
-		return;
+	while (try_extract_frame()) {
 	}
-
-	LOG_INF("CDC rx_flush submit proto_rx len:%u", (unsigned int)ctx.proto_rx_len);
-	(void)submit_proto_rx_event(PROTO_TRANSPORT_USB_CDC, proto_rx_buf,
-				    ctx.proto_rx_len);
-	ctx.proto_rx_len = 0U;
 }
 
 static void cdc_interrupt_handler(const struct device *dev, void *user_data)
@@ -408,7 +426,6 @@ static int do_init(void)
 
 	reset_ring_buffers();
 	k_work_init(&ctx.rx_work, rx_work_handler);
-	k_work_init_delayable(&ctx.rx_flush_work, rx_flush_work_handler);
 	uart_irq_callback_set(ctx.cdc_dev, cdc_interrupt_handler);
 	ctx.business = USB_CDC_BUS_OFFLINE;
 	ctx.usb_active = false;