ForRelease mints a per-call token used as the iframe id and threaded into the src as EmbedId; the host script matches on it so multiple embeds resize independently. ForTrack unchanged.
Read-only inline queue panel below the release embed's player bar; row-jump reuses PlayRelease. ForRelease mints a taller iframe plus a postMessage resize listener for the collapse toggle; ForTrack unchanged.
The queue gains an armed-but-idle state (Arm/Start) so a release embed stages track 0 prerender-safe, then queues the full release on first play and auto-advances.
daniel-c-harvey