Stable identifier for THIS embed within the document. Used by the presenter-sync "force focus on this embed" flow (Phase 5) so a teacher can scroll a student's viewer to a specific embed.
File identifier the consumer's resolveFile uses to fetch a URL or
presigned link. Opaque to the SDK.
Embed kind — drives the card icon and the open behaviour.
Display name shown in the card.
Attributes persisted on each
assignment-embednode in the TipTap document. Stable across editor + viewer; both read/write the same shape.