fix: 修复桌面端文章目录没有自动滚动跟随的问题

- 添加 indexScrollBoxSelector 配置项，指向侧边栏滚动容器
- 添加 scrollSelector 和 scrollWrap 配置，确保滚动监听正常工作
- 设置 defaultExpanded 为 true，保持目录子项默认展开
- 修复目录高亮后无法自动滚动到可视区域的问题

sidebar.php

@@ -527,10 +527,14 @@ $author_desc = get_option('argon_sidebar_author_description');
 												$(document).headIndex({
 													articleWrapSelector: '#post_content',
 													indexBoxSelector: '#leftbar_catalog',
+													indexScrollBoxSelector: '#leftbar_part2_inner',
+													scrollSelector: 'body,html',
+													scrollWrap: window,
 													subItemBoxClass: "index-subItem-box",
 													itemClass: "index-item",
 													linkClass: "index-link",
 													offset: 80,
+													defaultExpanded: true
 												});
 											});
 										} else {