ui: remove PetZone sidebar box (Mochi lives next to Kira now)

frontend/src/App.tsx

@@ -5,7 +5,6 @@ import Timer from './components/Timer';
 import Notes from './components/Notes';
 import WhiteNoise from './components/WhiteNoise';
 import KiraAvatar from './components/KiraAvatar';
-import PetZone from './components/PetZone';
 import Wardrobe from './components/Wardrobe';
 import Particles from './components/Particles';
 import WelcomeScreen from './components/WelcomeScreen';
@@ -170,7 +169,6 @@ export default function App() {
               <Wardrobe onOutfitChange={handleOutfitChange} onAccessoryChange={handleAccessoryChange} />
             </div>
             <div className="shrink-0 pt-2">
-              <PetZone />
             </div>
           </div>
         </div>