Preload notification audio and add AudioPreloader component

Added an AudioPreloader React component to preload the /hohoho.mp3 audio file for notifications, and included it in the app layout. Also updated _document.tsx to add a preload link for the audio file. Added yt-dlp.exe binary to the repository.

components/audio-preloader.tsx

@@ -0,0 +1,27 @@
+"use client"
+
+import { useEffect } from "react"
+
+/**
+ * Preloads the notification audio file to ensure it's ready when needed
+ */
+export function AudioPreloader() {
+  useEffect(() => {
+    // Preload the audio file
+    const audio = new Audio('/hohoho.mp3')
+    audio.preload = 'auto'
+    
+    // Try to load it immediately
+    audio.load().catch(err => {
+      console.log('Audio preload failed (non-critical):', err)
+    })
+
+    return () => {
+      // Cleanup
+      audio.src = ''
+    }
+  }, [])
+
+  return null
+}
+