refactor(navigation): 重构Navigation类继承unitree::robot::Client

移除不必要的client_成员变量，直接继承unitree::robot::Client类
简化初始化逻辑，更新相关文档说明

README.md

@@ -429,7 +429,7 @@ unitree-go2/
 │   ├── custom_robot.hpp    # Main orchestrator
 │   ├── logger.hpp          # Logging system
 │   ├── mqtt.hpp            # MQTT client
-│   ├── navigation.hpp      # Navigation and SLAM
+│   ├── navigation.hpp      # Navigation and SLAM (inherits from unitree::robot::Client)
 │   └── nlohmann/           # JSON library
 ├── src/                    # Source files
 │   ├── config.cpp          # Configuration implementation
@@ -438,7 +438,7 @@ unitree-go2/
 │   ├── logger.cpp          # Logging system implementation
 │   ├── main.cpp            # Entry point
 │   ├── mqtt.cpp            # MQTT client implementation
-│   └── navigation.cpp      # Navigation and SLAM implementation
+│   └── navigation.cpp      # Navigation and SLAM implementation (inherits from unitree::robot::Client)
 ├── scripts/                # Utility scripts
 │   ├── install_deps.sh     # Install dependencies
 │   └── run_robot.sh        # Run with optimal settings