fix: 在接收消息时添加对私信类型的处理逻辑，确保消息结构的完整性

ws_client/client.go

@@ -86,11 +86,13 @@ func (c *WebSocketClient) receiveMessages() {
 				GroupId:    event.GroupID,
 				UserCard:   event.Sender.Card,
 			}
-		} else {
+		} else if event.MessageType == constants.PRIVATE_MSG {
 			msg.GroupInfo = model.GroupInfo{
 				IsGroupMsg: false,
 				GroupId:    event.Sender.GroupID,
 			}
+		} else {
+			return
 		}
 		go func() {
 			reply := handler.MsgInHandler(msg)