The (opaque) document UUID.
The document's logic, or undefined if unresolved.
The logic-layer counterpart of fromUuidSync: it hides the Foundry
document entirely, returning only the logic, so the logic layer can treat a
UUID as an opaque token and round-trip it back to logic. Like fromUuidSync,
it returns undefined for documents not already in memory (e.g. unloaded
compendium entries) — use fvttLogicFromUuid when that is possible.
Resolve a document UUID to its SoHL logic instance, synchronously.