refactor(device): 重构SPI命令处理为模块化架构

- 将原有的 monolithic app_spi_command.cpp 拆分为多个专门的命令处理器文件
- 新增 spi_command_handler.h 定义命令处理器接口和上下文结构
- 新增 app_spi_command_defs.h 提取公共协议常量定义
- 新增多个具体命令处理器实现文件：
  - app_spi_cmd_boot_request.cpp (进入Bootloader命令)
  - app_spi_cmd_ota_wait.cpp (OTA等待响应命令)
  - app_spi_cmd_ping.cpp (APP心跳ping命令)
  - app_spi_cmd_can_bridge.cpp (SPI到CAN桥接命令)

- 修改 app_spi_command.cpp 仅负责SPI链路管理和命令路由逻辑
- 更新配置文件添加新源文件到项目编译列表
- 调整全局实例为对象实例(AppSpiCommandBus)，移除静态方法依赖
- 更新README文档说明新的SPI命令总线拆分架构
- 微调版本号(patch: 0 -> 1, build: 2 -> 0)

GD32E508_DCU_APP/GD32E508_DCU_APP.cproject.yml

@@ -1,4 +1,4 @@
-# A project translates into one executable or library.
+# A project translates into one executable or library.
 project:
 
   groups:
@@ -18,6 +18,7 @@ project:
         - file: ./sys/task_runner.cpp
         - file: ./sys/ota_boot_request.h
         - file: ./sys/ota_boot_request.cpp
+        - file: ./sys/cpp_stubs.cpp
         - file: ./sys/config.h
     - group: device
       files:
@@ -29,6 +30,12 @@ project:
         - file: ./device/CANFD.cpp
         - file: ./device/app_spi_command.h
         - file: ./device/app_spi_command.cpp
+        - file: ./device/spi_command_handler.h
+        - file: ./device/app_spi_command_defs.h
+        - file: ./device/app_spi_cmd_boot_request.cpp
+        - file: ./device/app_spi_cmd_ota_wait.cpp
+        - file: ./device/app_spi_cmd_ping.cpp
+        - file: ./device/app_spi_cmd_can_bridge.cpp
         - file: ./device/Timer.h
         - file: ./device/Timer.cpp
         - file: ./device/temp_sensor.h