perf: completely fix non-composited animations, eliminate shutter unused JS, and aggressively compress images

components/providers/TransitionProvider.tsx

@@ -27,14 +27,8 @@ export function TransitionProvider({ children }: { children: ReactNode }) {
   const [hasMountedShutter, setHasMountedShutter] = useState(false);
   const router = useRouter();
 
-  // Load the heavy shutter chunk in the background when the main thread is idle
-  useEffect(() => {
-    if (typeof window !== 'undefined' && 'requestIdleCallback' in window) {
-      window.requestIdleCallback(() => setHasMountedShutter(true));
-    } else {
-      setTimeout(() => setHasMountedShutter(true), 2000);
-    }
-  }, []);
+  // We no longer eagerly load the shutter in the background.
+  // It will be loaded precisely when the user initiates a transition.
 
   // We use a ref to track transition state without triggering the route change effect when it turns true
   const isTransitioningRef = React.useRef(isTransitioning);