Switch notification sound to hohoho.mp3 and add download script

Replaced all references to notification.mp3 with hohoho.mp3 in notification-related components and context. Added hohoho.mp3 to the public directory. Introduced a script (download-notification-sound.js) for downloading notification sounds from YouTube using @distube/ytdl-core, which was added as a devDependency. Also added yt-dlp.exe for alternative audio downloading.

components/notifications/OrderNotifications.tsx

@@ -33,9 +33,9 @@ export default function OrderNotifications() {
   const audioRef = useRef<HTMLAudioElement | null>(null);
 
   useEffect(() => {
-    audioRef.current = new Audio('/notification.mp3');
+    audioRef.current = new Audio('/hohoho.mp3');
     
-    // Fallback if notification.mp3 doesn't exist
+    // Fallback if hohoho.mp3 doesn't exist
     audioRef.current.addEventListener('error', () => {
       audioRef.current = null;
     });