The 'part of the performance' light: a room receiver announces itself to its OWN Mac's Menu Band over a local roomGuest distributed notification (start, 30 s heartbeat, atexit goodbye), and that Menu Band spins the Juke disc reading 'room right ← neo' while the machine carries someone else's channel — guarded so the badge never covers a real local Juke display, and self-retiring after three missed heartbeats so a SIGKILLed receiver can't leave a phantom disc master