feat(ui): update app layout and command palette

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/web/frontend/src/App.tsx

@@ -394,7 +394,7 @@ const App: React.FC = () => {
             eventCount: w.eventCount + 1,
             status: 'active' as const,
             currentTool: event.tool,
-            recentEvents: [...w.recentEvents.slice(-9), event],
+            recentEvents: [...(w.recentEvents ?? []).slice(-9), event],
           } : w);
         } else {
           return [...prev, {

src/web/frontend/src/components/CommandPalette.tsx

@@ -37,6 +37,7 @@ const DEFAULT_COMMANDS: CommandSuggestion[] = [
   { id: 'show-cost', label: 'Show cost dashboard', category: 'Commands', action: 'show:cost', icon: '💰' },
   { id: 'show-budget', label: 'Show budget alerts', category: 'Commands', action: 'show:budget', icon: '%' },
   { id: 'show-errors', label: 'Show error groups', category: 'Commands', action: 'show:errors', icon: '🐛' },
+  { id: 'show-narrative', label: 'Show semantic narrative', category: 'Commands', action: 'show:narrative', icon: '📝' },
   // Focus mode
   { id: 'focus-toggle', label: 'Toggle focus mode', category: 'Commands', action: 'focus:toggle', icon: '📌' },
   { id: 'focus-clear', label: 'Clear pinned items', category: 'Commands', action: 'focus:clear', icon: '📍' },