Implement Phase 3 audio gaps: continuous beds (zocalo chatter, teletype chatter, heterodyne drone)

js/app.js

@@ -301,6 +301,10 @@ document.addEventListener('DOMContentLoaded', () => {
     if (presetId === 'bio-vorlon') expandedAudio.startVorlonSong(); // #26
     if (presetId === 'bio-wraith') expandedAudio.startHullRegen(); // #28
     if (presetId === 'deep-event-horizon' || presetId === 'deep-icarus-ii') expandedAudio.startHullStrainMoans(); // #30
+    // Phase 3 (audio_gaps.md #46-#54)
+    if (presetId === 'sta-babylon-5') expandedAudio.startZocaloChatter(); // #46
+    if (presetId === 'ind-nostromo') expandedAudio.startTeletypeChatter(); // #51
+    if (presetId === 'ret-jupiter-2') expandedAudio.startHeterodyneDrone(); // #54
     if (presetId === 'deep-icarus-ii') expandedAudio.startIcarusBeacon(); // #31
     if (presetId === 'deep-event-horizon' || presetId === 'deep-nightflyer') expandedAudio.startVoidWhispers(); // #32
     if (presetId === 'com-protector') expandedAudio.startBerylliumThrum(); // #33
@@ -935,6 +939,14 @@ document.addEventListener('DOMContentLoaded', () => {
       case 'btn-teletype':
         expandedAudio.synthesizeTeletypeChatterPhrase();
         break;
+      case 'btn-zocalo-chatter':
+        if (expandedAudio.zocaloChatterActive) expandedAudio.stopZocaloChatter();
+        else expandedAudio.startZocaloChatter();
+        break;
+      case 'btn-hetero-drone':
+        if (expandedAudio.heterodyneDroneActive) expandedAudio.stopHeterodyneDrone();
+        else expandedAudio.startHeterodyneDrone();
+        break;
 
       default:
         telemetry.synthesizeLCARSSingleChirp();