setNext() appended raw content:// URIs that mpv cannot open, stalling
playback at the SD-card-download track boundary. Convert to fdclose://
like open(), track the armed fd, and reclaim it via a new closeContentFd
method when the entry is dropped unplayed (close only when provably
unconsumed — playlist-pos 0 before and after the remove; leak on doubt).
The playlist-pos pre-check also keeps the clear path from removing the
playing entry when mpv rolls into the armed track mid-clear.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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.
edde746