feat(grouping): 新增分组功能并优化 Markdown 文件操作

- 新增分组实体、控制器、服务和映射器
- 实现分组创建、获取、更新和删除接口
- 优化 Markdown 文件创建、获取和删除接口- 新增全局异常处理和日志记录
- 更新数据库表结构和字段类型
- 重构前端页面，支持分组和 Markdown 文件展示

biji-houdaun/src/main/java/com/test/bijihoudaun/entity/MarkdownFile.java

@@ -7,7 +7,7 @@ import com.baomidou.mybatisplus.annotation.TableName;
 import io.swagger.v3.oas.annotations.media.Schema;
 import lombok.Data;
 
-import java.time.LocalDateTime;
+import java.util.Date;
 
 @Data
 @Schema(name = "文本实体")
@@ -16,7 +16,9 @@ public class MarkdownFile {
     @Schema(description = "文本id",implementation = Long.class)
     @TableId(type = IdType.AUTO)
     private Long id;
-    @Schema(description = "用户id",implementation = Long.class)
+    @Schema(description = "分组表id",implementation = Long.class)
+    private Long groupingId;
+    @Schema(description = "用户ID",implementation = Long.class)
     private Long userId;
     @Schema(description = "文本标题",implementation = String.class)
     private String title;
@@ -27,8 +29,8 @@ public class MarkdownFile {
 
     @Schema(description = "Markdown内容，存储实际文档内容",implementation = String.class)
     private String content;
-    @Schema(description = "创建时间",implementation = LocalDateTime.class)
-    private LocalDateTime createdAt;
-    @Schema(description = "更新时间",implementation = LocalDateTime.class)
-    private LocalDateTime updatedAt;
+    @Schema(description = "创建时间",implementation = Date.class)
+    private Date createdAt;
+    @Schema(description = "更新时间",implementation = Date.class)
+    private Date updatedAt;
 }