refactor: improve path handling in folder viewer

- Updated path splitting logic to retain leading slashes for absolute paths while filtering out empty segments.
- Enhanced parent path reconstruction to ensure correct navigation within the folder structure.
- Improved readability and maintainability of the path management code.

src/app/folder-viewer/page.tsx

@@ -174,12 +174,18 @@ const FolderViewerPage = () => {
     // Don't allow navigation above library root
     if (currentPath === libraryRoot) return '';
     
-    const pathParts = currentPath.split('/').filter(part => part.length > 0);
+    // Split path but keep leading slash for absolute paths
+    const pathParts = currentPath.split('/');
     const libraryParts = libraryRoot.split('/').filter(part => part.length > 0);
     
-    if (pathParts.length <= libraryParts.length) return '';
+    // Filter out empty parts but keep structure
+    const filteredPathParts = pathParts.filter(part => part.length > 0);
     
-    return pathParts.slice(0, -1).join('/');
+    if (filteredPathParts.length <= libraryParts.length) return '';
+    
+    // Reconstruct absolute path
+    const parentParts = filteredPathParts.slice(0, -1);
+    return '/' + parentParts.join('/');
   };
 
   const handleBackClick = () => {