feat(export): 新增文章封面字段支持

- 在 ExportArticle 实体类中添加 cover 字段
- 在 ExportArticleBo 业务对象中添加 cover 字段
- 在 ExportArticleMapper.xml 中配置 cover 字段映射
- 在 ExportArticleVo 视图对象中添加 cover 字段
- 支持文章导出时包含封面信息

fad-export/src/main/java/com/ruoyi/export/domain/ExportArticle.java

@@ -75,4 +75,7 @@ public class ExportArticle extends BaseEntity {
      */
     private String remark;
 
+    //新增封面字段
+    private String cover;
+
 }

fad-export/src/main/java/com/ruoyi/export/domain/bo/ExportArticleBo.java

@@ -78,5 +78,8 @@ public class ExportArticleBo extends BaseEntity {
      */
     private String remark;
 
+    //新增封面字段
+    private String cover;
+
 
 }

fad-export/src/main/java/com/ruoyi/export/domain/vo/ExportArticleVo.java

@@ -88,5 +88,8 @@ public class ExportArticleVo {
     @ExcelProperty(value = "备注")
     private String remark;
 
+    //新增封面字段
+    private String cover;
+
 
 }

fad-export/src/main/resources/mapper/export/ExportArticleMapper.xml

@@ -15,6 +15,7 @@
         <result property="isPublished" column="is_published"/>
         <result property="publishedTime" column="published_time"/>
         <result property="sortOrder" column="sort_order"/>
+        <result property="cover" column="cover" />
         <result property="delFlag" column="del_flag"/>
         <result property="remark" column="remark"/>
         <result property="createTime" column="create_time"/>