fix: mobile menu overlay, speech bubble timing, TTS static file fallback

- Mobile nav menu now overlays content (absolute positioning) instead of
  pushing it down
- Speech bubbles stay visible for minimum 400ms even when TTS resolves
  instantly or fails
- kokoroPlayCached checks audio cache and loads static files even when
  Kokoro worker hasn't loaded — fixes TTS not playing on production
- CORS_ORIGIN env now supports comma-separated origins
- Rename "VIDEO REPLAY" to play icon + "REPLAY"

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/game/audio/voice.ts

@@ -788,10 +788,11 @@ export function playNarrationNow(text: string): Promise<void> {
 async function _playNowCore(text: string, profileName: string, rateOverride?: number): Promise<void> {
   if (getMasterMuted()) return
   const sfxGain = getSfxGain()
-  if (isKokoroReady() && sfxGain) {
+  // Try Kokoro (includes pre-generated static files from cache)
+  if (sfxGain) {
     const profile = voiceProfiles[profileName] || voiceProfiles.announcer
-    await kokoroPlayCached(text, profileName, sfxGain, profile.volume * VOICE_VOLUME_SCALE)
-    return
+    const played = await kokoroPlayCached(text, profileName, sfxGain, profile.volume * VOICE_VOLUME_SCALE)
+    if (played) return
   }
   // Fallback to Web Speech
   return _speakAsyncCore(text, profileName, rateOverride)

frontend/src/game/tts.ts

@@ -510,22 +510,37 @@ export async function kokoroAwaitReady(text: string, profileName: string): Promi
   } catch { return false }
 }
 
-/** Play already-cached audio immediately. Returns playback promise. If not cached, returns resolved. */
-export function kokoroPlayCached(
+/** Play already-cached audio immediately. Returns true if played, false if nothing available. */
+export async function kokoroPlayCached(
   text: string,
   profileName: string,
   dest: AudioNode,
   volume: number = 0.7,
-): Promise<void> {
-  if (!_workerReady) return Promise.resolve()
+): Promise<boolean> {
   const key = _cacheKey(text, profileName)
+  // Check in-memory cache first (includes pre-loaded static files)
   const cached = audioCache.get(key)
   if (cached) {
     cached.lastAccess = Date.now()
-    return _playBuffer(cached.buf, dest, volume)
+    await _playBuffer(cached.buf, dest, volume)
+    return true
   }
-  // Not cached — fall through to generate+play
-  return kokoroSpeakAsync(text, profileName, dest, volume).then(() => {})
+  // Try loading static file on demand if not in cache yet
+  const staticUrl = STATIC_AUDIO[key]
+  if (staticUrl) {
+    const buf = await _loadStaticAudio(staticUrl)
+    if (buf) {
+      audioCache.set(key, { buf, lastAccess: Date.now() })
+      await _playBuffer(buf, dest, volume)
+      return true
+    }
+  }
+  // Try worker generation if available
+  if (_workerReady) {
+    const played = await kokoroSpeakAsync(text, profileName, dest, volume)
+    return played
+  }
+  return false
 }
 
 /** Stop all currently playing kokoro audio */