Participant.lastKnownPosition had zero reads or writes; SessionState.disconnected was never constructed, making isInSession's comparison tautological (now _session != null); the session indicator's onLeaveSession callback had no production passer; enterRoom's bool was awaited and discarded. Music engine: MusicPlayContext.id and sleepTimerEndsAt were write-only, and the coordinator constructor seam was never injected.
Guests joining an "Anyone" room saw "Host controls playback" and a
locked room until the host actually started something. Control mode
only travelled inside the host's PlaybackState broadcast, and every
broadcast path requires an active media epoch, so an idle lobby had no
carrier at all: guests sat on the joinAsGuest hostOnly default. The v1
protocol's sessionConfig message covered this; the v3 rewrite lost it.
Carry the mode on the host's join messages instead: the directed join
reply every participant already sends to a new peer, and the host's
reconnect re-announce. The field is optional on the wire ('cm'), so
older clients ignore it and rooms with older hosts degrade to the
previous behavior. Guests apply it only from the relay-derived host
peer ID, never from a join's own spoofable isHost flag.
close#1950
Replaces the imperative play/pause/seek/positionSync message soup with a
single host-authored PlaybackState (seq-ordered, anchor-extrapolated,
phase machine: loading/waitingForPeers/paused/playing) that doubles as
the heartbeat, plus guest status reports and host-applied control
requests. Fixes the guest seek-back loop while the host loads (readiness
was keyed on a pre-load !buffering snapshot and heartbeats broadcast
frozen positions), adds real group buffering coordination (stall grace,
scheduled simultaneous resumes, 15s safety timeout), rate-nudge drift
correction with passthrough-aware seek fallback, session-scoped message
handling (no lost messages during episode-switch detach gaps), and an
expected-state ledger replacing the racy remote-action flag.
- Reset _firstPlayCompleted on detach so episode switches wait for peers
- Remove duplicate host join announcement from sync manager
- Use dedicated isPlaying field in sessionConfig with legacy fallback
- Replace Future.delayed with cancellable Timer to prevent sync indicator flicker
- Make Participant fields final and constructor const
edde746