#707 wrote generated start/stop files for the family picker. Swap those
for the downloaded preview bytes (voca is pair 05) and skip the catalog
ids in generate_sounds.py so they stay put.
Settings → Audio can pick start/stop cues from the shared catalog
(lift, flick, ember, step, voca, soft, chirp, scale, drop, glass, off).
New installs and any missing or unknown sound_effects.tone value use
voca. A saved id, including off, is left alone.
The old start_recording/stop_recording files stay on disk. They are
no longer the implicit default. Error cues still follow the existing
enable switch.
