feat: 侧边栏文件夹目录树添加标题头

renderer/renderer.js

@@ -1498,11 +1498,16 @@
     return section;
   }
 
-  // Override renderTree to cache data and prepend independent files
+  // Override renderTree to cache data, add header, and prepend independent files
   const _originalRenderTree = renderTree;
   renderTree = function(tree, rootPath) {
     lastTreeData = tree;
     _originalRenderTree(tree, rootPath);
+    // Add folder tree header
+    const folderHeader = document.createElement('div');
+    folderHeader.className = 'sidebar-section-header';
+    folderHeader.textContent = '文件夹目录树';
+    sidebarTree.insertBefore(folderHeader, sidebarTree.firstChild);
     // Prepend independent files section
     const indepSection = renderIndependentFiles();
     if (indepSection) {

renderer/style.css

@@ -867,6 +867,8 @@ html, body {
   padding-bottom: 4px;
 }
 
+/* ===== Sidebar Section Headers ===== */
+.sidebar-section-header,
 .independent-files-header {
   font-size: 11px;
   font-weight: 600;