OptionalCaptionOptional one-line caption beneath the media.
Short tab label.
OptionalFileId of an "MJ: Files" record this item is backed by. When set, the item is streamed securely
(permission-gated) from MJStorage rather than from a public Url; the surface resolves a
short-lived streaming URL (via CreateMediaAccessToken) or hands the id straight to
mj-storage-media-player for audio/video.
OptionalHighlightOptional fractional highlight overlay.
Stable id (returned to the agent by Media_ShowMedia, used by close/play/highlight).
OptionalPlaySet transiently to request playback of a video/audio item (consumed by the surface).
Which render path the pane uses.
OptionalUrlAbsolute URL of the media — for an EXTERNAL/public asset. Optional/empty when FileID
is set (the surface resolves a secure streaming URL from the file id instead). At least one of
Url / FileID is always present.
One piece of media on the surface — a tab + a render pane keyed by MediaItemType.