feat(network): add NetworkServer for managing player sessions and communication

- Implemented `NetworkServer` and `Session` classes for handling TCP communication with players.
- Added `NetworkServer.cpp` and `NetworkServer.h` to the project.
- Integrated `asio` library into the build configuration in `CMakeLists.txt`.

src/network/NetworkServer.h

@@ -0,0 +1,77 @@
+/**
+ * @file NetworkServer.h
+ *
+ * @author Yuzhe Guo
+ * @date 2025.11.25
+ */
+#pragma once
+#include "Message.h"
+
+
+#include <asio.hpp>
+#include <map>
+#include <memory>
+
+namespace UNO::NETWORK {
+
+    class Session : public std::enable_shared_from_this<Session> {
+    private:
+        size_t player_id_;
+        asio::ip::tcp::socket socket_;
+        std::function<void(size_t, std::string)> callback_;
+
+    public:
+        Session(size_t player_id, asio::ip::tcp::socket socket);
+
+        /**
+         * 开始从网络读取消息
+         * @param callback 回调函数
+         */
+        void start(std::function<void(size_t, std::string)> callback);
+
+        /**
+         * 发送消息
+         * @param message 要发送的消息
+         */
+        void send(const std::string &message);
+
+    private:
+        void read();
+        void readBody(size_t length);
+    };
+
+    class NetworkServer {
+    private:
+        asio::io_context io_context_;
+        asio::ip::tcp::acceptor acceptor_;
+        size_t playerCount;
+        std::map<size_t, std::shared_ptr<Session>> sessions_;
+        std::function<void(size_t, std::string)> callback_;
+        std::mutex mutex_;
+
+    public:
+        explicit NetworkServer(uint16_t port, std::function<void(size_t, std::string)> callback);
+
+        /**
+         * 添加玩家
+         * @param socket 玩家的连接 socket
+         */
+        void addPlayer(asio::ip::tcp::socket socket);
+
+        /**
+         * 向玩家发送消息
+         * @param id 要发送到的玩家 id
+         * @param message 要发送的消息
+         */
+        void send(size_t id, const std::string &message);
+
+        /**
+         * 开始网络进程
+         */
+        void run();
+
+    private:
+        void accept();
+    };
+
+}   // namespace UNO::NETWORK