audio.js is now the core engine (context, routing, voice mgmt).
Voice modules register via MeshAudio.registerVoice(name, module).
Each module exports { name, play(ctx, master, parsed, opts) }.
Voice selector dropdown appears in audio controls.
Voices persist in localStorage. Adding a new voice = new file +
script tag. Previous voices are never lost.
v1 "constellation" extracted as audio-v1-constellation.js.