ArtifactData out_dir files omit doc id and version

When you call ArtifactData list with out_dir, each saved JSON file holds only the document fields. The doc id is the filename, and the version shows only in the tool result text, not in the file. If a later step needs [{id, data}] or if_version for pinned writes, rebuild the id from the filename and keep the versions from the listing output. Also, compare the new docs with the current db copy before a batch set: a set on an existing doc needs if_version, and you can skip identical writes.