fix(nav): remove toggle behavior on navigation tabs (#417)

Clicking an already-active navigation tab previously toggled back to
the dashboard/editor view. This was a holdover from the old UI where
the tab buttons were different. Under the current design it causes
confusion, so clicking the active tab now does nothing.

frontend/src/components/EditorLayout.tsx

@@ -249,12 +249,9 @@ export default function EditorLayout() {
     setIsEditing(false);
   };
 
-  // Navigation handler with toggle support
   const handleNavigate = (value: string) => {
-    if (value === activeView) {
-      // Toggle off: return to editor if a file is open, else dashboard
-      setActiveView(selectedFile ? 'editor' : 'dashboard');
-    } else if (value === 'dashboard') {
+    if (value === activeView) return;
+    if (value === 'dashboard') {
       resetEditorState();
       setActiveView('dashboard');
     } else {