The "should we make noise" predicate used for message sounds is extracted
into useNotificationsQuiet() (unit-tested) and applied to the ringtone in
both the full-screen incoming-call overlay and the compact in-call banner.
The overlay/banner still show so the call can be answered; only the audio
is skipped. Join/media paths untouched.
Fixes#28
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPmy3tPq869XDW4njjVaKA
