feat: leftsidebar collapsible tool groups + scroll + resizable width

frontend/src/App.tsx

@@ -149,6 +149,7 @@ const CADEditor: React.FC<CADEditorProps> = ({ projectId, token, onNavigateBack
   const [mobileRightOpen, setMobileRightOpen] = useState(false);
   // Desktop sidebar collapse
   const [leftSidebarCollapsed, setLeftSidebarCollapsed] = useState(false);
+  const [leftbarWidth, setLeftbarWidth] = useState(200);
   const [rightSidebarCollapsed, setRightSidebarCollapsed] = useState(false);
   const [settingsOpen, setSettingsOpen] = useState(false);
   const [activeDrawerTab, setActiveDrawerTab] = useState<DrawerTab>('tool');
@@ -1553,6 +1554,8 @@ const CADEditor: React.FC<CADEditorProps> = ({ projectId, token, onNavigateBack
           onSaveGroupAsBlock={handleSaveGroupAsBlock}
           onGroup={() => handleRibbonAction('group')}
           onUngroup={() => handleRibbonAction('ungroup')}
+          leftbarWidth={leftbarWidth}
+          onWidthChange={setLeftbarWidth}
         />
         <CanvasArea
           cursorPos={cursorPos}