fix: use correct folders endpoint /folders?projectId=X instead of /projects/:id/folders

public/js/api.js

@@ -143,8 +143,9 @@ class ApiClient {
 
   // ===== FOLDERS =====
   getFolders(projectId, parentId = null) {
-    const query = parentId ? `?parentId=${parentId}` : '';
+    const params = new URLSearchParams({ projectId });
-    return this.get(`/projects/${projectId}/folders${query}`);
+    if (parentId) params.append('parentId', parentId);
+    return this.get(`/folders?${params.toString()}`);
   }
 
   createFolder(data) {