The board stays hidden by default, so new phones could only pair via an SSH session. Add 'radxa-audio discoverable on|off' backed by a transient radxa-bt-pairing unit that auto-approves and trusts devices pairing in the window, expires on its own, and expose it in the web mixer with a countdown. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>