fix: mobile sidebar slide-in overlay with hamburger and panel toggle buttons

- LeftSidebar/RightSidebar: added className prop for 'open' class
- Topbar: wired hamburger onClick + added mobile-drawer-toggle button for right panel
- App.tsx: added SettingsModal import/state/render, passed className props to sidebars
- styles.css: mobile sidebars now fixed slide-in overlays (translateX) instead of display:none
- ui.types.ts: added className to RightSidebarProps, onOpenLeftDrawer/onOpenRightDrawer to TopbarProps
- Tested at 390px viewport: both sidebars slide in correctly, transform verified via DOM

frontend/src/App.tsx

@@ -18,6 +18,7 @@ import StatusBar from './components/StatusBar';
 import MobileDrawers from './components/MobileDrawers';
 import BackgroundImport from './components/BackgroundImport';
 import HistoryPanel from './components/HistoryPanel';
+import SettingsModal from './components/SettingsModal';
 import { BackgroundService, type BackgroundConfig } from './services/backgroundService';
 import { HistoryManager, type CADStateSnapshot, type HistoryEntry } from './history';
 import { getCommandRegistry } from './services/commandRegistry';
@@ -146,6 +147,7 @@ const CADEditor: React.FC<CADEditorProps> = ({ projectId, token, onNavigateBack
   // Mobile drawers
   const [mobileLeftOpen, setMobileLeftOpen] = useState(false);
   const [mobileRightOpen, setMobileRightOpen] = useState(false);
+  const [settingsOpen, setSettingsOpen] = useState(false);
   const [activeDrawerTab, setActiveDrawerTab] = useState<DrawerTab>('tool');
 
   // Background
@@ -936,6 +938,9 @@ const CADEditor: React.FC<CADEditorProps> = ({ projectId, token, onNavigateBack
         onRedo={handleRedo}
         onThemeToggle={handleThemeToggle}
         theme={theme}
+        onOpenSettings={() => setSettingsOpen(true)}
+        onOpenLeftDrawer={() => setMobileLeftOpen(true)}
+        onOpenRightDrawer={() => setMobileRightOpen(true)}
       />
       <RibbonBar
         activeTab={activeRibbonTab}
@@ -948,6 +953,7 @@ const CADEditor: React.FC<CADEditorProps> = ({ projectId, token, onNavigateBack
           onToolChange={handleToolChange}
           selectedTemplate={selectedTemplate}
           onTemplateSelect={handleTemplateSelect}
+          className={mobileLeftOpen ? 'open' : ''}
         />
         <CanvasArea
           cursorPos={cursorPos}
@@ -1010,6 +1016,7 @@ const CADEditor: React.FC<CADEditorProps> = ({ projectId, token, onNavigateBack
           onKISend={handleKISend}
           onKISuggestionClick={handleSuggestionClick}
           kiLoading={kiLoading}
+          className={mobileRightOpen ? 'open' : ''}
         />
       </div>
       <CommandLine
@@ -1040,6 +1047,7 @@ const CADEditor: React.FC<CADEditorProps> = ({ projectId, token, onNavigateBack
         onCloseRight={() => setMobileRightOpen(false)}
         onRightTabChange={setActiveDrawerTab}
       />
+      <SettingsModal open={settingsOpen} onClose={() => setSettingsOpen(false)} />
       <BackgroundImport
         open={bgImportOpen}
         onClose={() => setBgImportOpen(false)}