Preload audio clips on mount so first playthrough timing stays in sync.

src/mediaSounds.ts

@@ -1,6 +1,46 @@
 import type { MediaConfig } from './mediaConfig';
 
+const audioElements = new Map<string, HTMLAudioElement>();
+
+function ensureAudio(src: string): HTMLAudioElement {
+  let audio = audioElements.get(src);
+  if (!audio) {
+    audio = new Audio();
+    audio.preload = 'auto';
+    audio.src = src;
+    audioElements.set(src, audio);
+  }
+  return audio;
+}
+
+const AUDIO_URL_KEYS = [
+  'incorrectUrl',
+  'unlockConfirmUrl',
+  'celebrationPopUrl',
+  'celebrationHornUrl',
+] as const satisfies readonly (keyof MediaConfig)[];
+
+/** Fetch and decode audio clips so first playback is not delayed. */
+export function preloadAudioAssets(config: MediaConfig): void {
+  for (const key of AUDIO_URL_KEYS) {
+    ensureAudio(config[key]).load();
+  }
+}
+
 export function playClip(src: string): HTMLAudioElement {
+  const cached = audioElements.get(src);
+  if (cached) {
+    if (cached.paused || cached.ended) {
+      cached.currentTime = 0;
+      void cached.play();
+      return cached;
+    }
+
+    const fallback = new Audio(src);
+    void fallback.play();
+    return fallback;
+  }
+
   const audio = new Audio(src);
   void audio.play();
   return audio;