fix(frontend): 修复附件缩略图识别 & 弹窗换行显示

- 修复 isImageFile 通过文件后缀判断图片，解决编辑模式下缩略图不显示
- modal alert 系列支持 dangerouslyUseHTMLString，<br/> 换行生效
- 更新 showAttachmentDetail 换行
- 新增变更记录 docs/变更管理/code-adjust-record-2025-07-10-wuzilong.md

web/src/plugins/modal.ts

@@ -21,28 +21,33 @@ export default {
   // 弹出提示
   alert(content: any) {
     ElMessageBox.alert(content, '系统提示', {
-      confirmButtonClass: 'el-button--primary'
+      confirmButtonClass: 'el-button--primary',
+      // 允许在内容中使用 <br/> 等 HTML
+      dangerouslyUseHTMLString: true
     });
   },
   // 错误提示
   alertError(content: any) {
     ElMessageBox.alert(content, '系统提示', {
       type: 'error',
-      confirmButtonClass: 'el-button--primary'
+      confirmButtonClass: 'el-button--primary',
+      dangerouslyUseHTMLString: true
     });
   },
   // 成功提示
   alertSuccess(content: any) {
     ElMessageBox.alert(content, '系统提示', {
       type: 'success',
-      confirmButtonClass: 'el-button--primary'
+      confirmButtonClass: 'el-button--primary',
+      dangerouslyUseHTMLString: true
     });
   },
   // 警告提示
   alertWarning(content: any) {
     ElMessageBox.alert(content, '系统提示', {
       type: 'warning',
-      confirmButtonClass: 'el-button--primary'
+      confirmButtonClass: 'el-button--primary',
+      dangerouslyUseHTMLString: true
     });
   },
   // 通知提示