feat: Advanced file editor and file tree improvements (#444)

# Features
- File drag and drop upload: Support uploading files and folders via drag and drop
- Binary file handling: Detect binary files and display a friendly message instead of trying to edit them
- Folder download: Download folders as ZIP files (using JSZip library)
- Context menu integration: Full right-click context menu for file operations (rename, delete, copy path, download, new file/folder)

src/components/code-editor/hooks/useEditorSidebar.ts

@@ -65,12 +65,15 @@ export const useEditorSidebar = ({
         return;
       }
 
-      const container = resizeHandleRef.current?.parentElement;
-      if (!container) {
+      // Get the main container (parent of EditorSidebar's parent) that contains both left content and editor
+      const editorContainer = resizeHandleRef.current?.parentElement;
+      const mainContainer = editorContainer?.parentElement;
+      if (!mainContainer) {
         return;
       }
 
-      const containerRect = container.getBoundingClientRect();
+      const containerRect = mainContainer.getBoundingClientRect();
+      // Calculate new editor width: distance from mouse to right edge of main container
       const newWidth = containerRect.right - event.clientX;
 
       const minWidth = 300;