Symptom: listener saw camera tiles appear black, then vanish ~1.5s later.
Cause: remote MediaStreamTracks ALWAYS start in muted state until the
first RTP packet arrives. My watchVideoTrackForRemoval had a
'defensive' branch that scheduled a prune if the track was already
muted at attach time — so the moment we attached, the 1.5s timer
started, and if the publisher's encoder hadn't pushed a keyframe yet
(common for cameras), the tile was pruned before any frame rendered.
Fix: track a hasFlowed flag. Set true on the FIRST 'unmute' (RTP
actually arrived). Only schedule a prune on 'mute' events that fire
AFTER hasFlowed — those are the real 'publisher stopped sending' case.
Initial muted state is now ignored. Also bumped the debounce from
1.5s to 3s for extra safety on slow networks.
'ended' still removes immediately (terminal state, no debounce).
83 FSM tests green.
Russell Ballestrini
9869e7861d