Every user now gets a personal 0-1 volume for horn, TTS, and mic forward.
The value is stored as a fraction of the ceiling that applies to them, so
lowering the global admin gain quiets everyone immediately instead of
leaving stale absolute values behind.
Ceilings resolve in three layers: the global admin gain is the default
ceiling; the audioGainBoost flag raises it to an admin-editable hard cap
(default 0.5x horn, 0.8x TTS, 0.4x forward); Math.max keeps the flag from
ever lowering a ceiling if the global gain is set higher than a cap.
Preferences live in identity feature state rather than a cookie so they
follow the user and cannot be raised client-side. The rover exposes gain
as three ALSA masters, so the resolved gains pushed to a rover are those
of the socket currently holding audio control -- re-pushed on driver
join/leave and every turn rotation.
Co-Authored-By: Claude <noreply@anthropic.com>
legop3