NorskManager.prefetchImages() method
Pre-warm a node (Phase G, warm nodes): tell its worker to pull these image refs now, so a later job start there finds them local. Returns as soon as the worker has been told — the per-ref outcome arrives asynchronously on the event stream as imagesPrefetched, and the node’s heldImages inventory updates right behind it.
A failure on one ref never fails the others; each ref’s result says for itself.
Signature:
prefetchImages(nodeId: NodeId, imageRefs: string[]): Promise<void>;