Download a file or folder from a snapshot

Stream a single file's bytes, or a folder subtree as a tar archive, directly out of a snapshot — the box can be stopped or archived; the machine is never contacted. Use GET /snapshots/{snapshotId}/tree to list paths, then pass one here. Paths are relative to the snapshot root (same space as tree entries; docker volumes under __dockervol__/). An empty or / path downloads the whole snapshot as a tar. Folder responses set X-Snapshot-File-Count, X-Snapshot-Total-Size-Bytes and X-Snapshot-Skipped-Base-Image-Files headers; both response shapes set X-Snapshot-Entry-Kind (file or dir).