fix(network): ensure disconnect before connect in NetworkClient

- Added `disconnect` method to gracefully close existing connections before establishing a new one.
- Updated `connect` to call `disconnect` to prevent resource conflicts.

src/network/NetworkClient.cpp

@@ -16,11 +16,20 @@ namespace UNO::NETWORK {
 
     void NetworkClient::connect(const std::string &host, uint16_t port)
     {
+        this->disconnect();
         asio::ip::tcp::resolver resolver(io_context_);
         auto endpoints = resolver.resolve(host, std::to_string(port));
         asio::connect(socket_, endpoints.begin(), endpoints.end());
     }
 
+    void NetworkClient::disconnect()
+    {
+        if (socket_.is_open()) {
+            this->socket_.close();
+        }
+    }
+
+
     void NetworkClient::send(const std::string &message)
     {
         size_t length = message.size();

src/network/NetworkClient.h

@@ -26,6 +26,11 @@ namespace UNO::NETWORK {
          */
         void connect(const std::string &host, uint16_t port);
 
+        /**
+         * 关闭到服务端的连接
+         */
+        void disconnect();
+
         /**
          * 向服务端发送消息
          * @param message 要发送的消息