重构User_code目录结构：将文件组织到子文件夹中

主要更改：
- 将所有BSP外设文件移动到独立子文件夹（can/, fdcan/, uart/等）
- 将所有Component文件移动到独立子文件夹（pid/, filter/, cmd/等）
- 将所有Device文件移动到独立子文件夹（dr16/, bmi088/等）
- 更新代码生成器以支持新的文件夹结构
- 保持向后兼容性，支持从子文件夹或根目录加载模板
- 添加STRUCTURE.md文档说明新的目录结构

优势：
✅ 更好的代码组织和管理
✅ 便于添加、删除、修改模板
✅ 清晰的模块划分
✅ 向后兼容现有结构

assets/User_code/bsp/mm/mm.c

@@ -0,0 +1,30 @@
+/* Includes ----------------------------------------------------------------- */
+#include "bsp/mm.h"
+
+#include "FreeRTOS.h"
+
+/* USER INCLUDE BEGIN */
+
+/* USER INCLUDE END */
+
+/* Private define ----------------------------------------------------------- */
+/* Private macro ------------------------------------------------------------ */
+/* Private typedef ---------------------------------------------------------- */
+/* USER DEFINE BEGIN */
+
+/* USER DEFINE END */
+
+/* Private variables -------------------------------------------------------- */
+/* USER STRUCT BEGIN */
+
+/* USER STRUCT END */
+
+/* Private function  -------------------------------------------------------- */
+/* Exported functions ------------------------------------------------------- */
+inline void *BSP_Malloc(size_t size) { return pvPortMalloc(size); }
+
+inline void BSP_Free(void *pv) { vPortFree(pv); }
+
+/* USER FUNCTION BEGIN */
+
+/* USER FUNCTION END */

assets/User_code/bsp/mm/mm.h

@@ -0,0 +1,32 @@
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Includes ----------------------------------------------------------------- */
+#include <stddef.h>
+#include <stdint.h>
+
+/* USER INCLUDE BEGIN */
+
+/* USER INCLUDE END */
+
+/* Exported constants ------------------------------------------------------- */
+/* Exported macro ----------------------------------------------------------- */
+/* USER DEFINE BEGIN */
+
+/* USER DEFINE END */
+
+/* Exported types ----------------------------------------------------------- */
+/* Exported functions prototypes -------------------------------------------- */
+void *BSP_Malloc(size_t size);
+void BSP_Free(void *pv);
+
+/* USER FUNCTION BEGIN */
+
+/* USER FUNCTION END */
+
+#ifdef __cplusplus
+}
+#endif