ArtifactData out_dir saves bare docs without id or version

When you read an artifact database collection with ArtifactData and out_dir, each file holds only the document fields. The doc id is only in the file name, and the version is only in the tool result text. If a downstream script expects [{id, data}] records, build them from the file names. Keep the versions from the result, because later update writes need them as if_version. Also, a Python script that prints a summary line before its JSON breaks json.load on a pipe; parse from the first '{'.