feat: UI sounds, live LFO visualization, wire fix, worlds 7-12, bug fixes

- Add procedural UI sound effects (connect/disconnect, engine start/stop,
  level complete/fail, star earned, hint, navigation) via Tone.js
- Live LFO modulation visualization: knobs animate in real-time showing
  modulated value, ghost dot shows base value, number glows cyan
- Fix wire recalculation on zoom/pan/level re-entry (post-layout refresh)
- Fix retry button to keep current patch instead of reloading level
- Fix default param detection: newly added modules now populate all
  default params so level checkers work without manual param changes
- Add worlds 7-12: Secuencias y Ritmos, Texturas de Ruido, Síntesis
  Sustractiva, Espacio y Stereo, Técnicas Avanzadas, Gran Final
  (48 new levels, 144 new possible stars, 288 total stars)

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

src/App.jsx

@@ -3,6 +3,7 @@ import { state, subscribe, addModule, emit, addConnection, updateModulePosition,
 import { startAudio, stopAudio, connectWire, rebuildGraph } from './engine/audioEngine.js';
 import { getModuleDef } from './engine/moduleRegistry.js';
 import { autoSave, autoLoad, exportPatch, importPatch } from './engine/presets.js';
+import { playEngineStart, playEngineStop } from './engine/uiSounds.js';
 import ModuleNode from './components/ModuleNode.jsx';
 import WireLayer from './components/WireLayer.jsx';
 import ModulePalette from './components/ModulePalette.jsx';
@@ -193,8 +194,10 @@ export default function App({ onSwitchToGame }) {
   const handleToggleAudio = async () => {
     if (state.isRunning) {
       stopAudio();
+      playEngineStop();
     } else {
       await startAudio();
+      playEngineStart();
     }
     emit();
   };