Implement Phase 2 audio gaps: 25 medium-difficulty synthesizers and ambient loops
- 23 new ExpandedSciFiAudioSynth methods + 2 WhoniverseAudioSynth methods
covering audio_gaps.md rows #21-#45: Cardassian door, turbolift, replicator,
scanner activation, console type clatter, Vorlon song, neural-bond swell,
hull regen, Belter jury-rig telemetry, hull strain moan, Icarus beacon,
void whisper, Beryllium thrum, Omega-13, repulsorlift drone, Bebop chug,
carousel groan, slipstream surge, O2 regulator, pipe drips, steam vent,
crash-couch gimbal, HAL respiration, Death Blossom, Cygnus piston chug
- Keyed ambient-loop registry (_scheduleLoop/_stopLoop) replacing ad-hoc
timer fields; stopAllLoops clears registry plus legacy timers
- Single startPresetAmbience funnel in app.js engages ambience per preset on
engage/switch and tears down on full stop; whoniverse ambience stopped on
every preset change
- All 10 universe soundboards rebuilt (6-8 buttons each, span-2 Belter
telemetry); NEURAL PULSE event now fires the real neural-bond swell
- TelemetrySynth era routing intentionally untouched (Phase 3 scope); docs
updated in audio_gaps.md and sound_reference.md