Convert MLflow to ATIF

Purpose

Produce canonical ATIF without routing trace data through Intake. The bundled script writes one owner-private .atif.json file per MLflow trace and prints only a content-free summary.

For shared normalized span evidence, read NeMo Compass ingestion and use the optional scripts/load_mlflow_trace.py command. Its output is not ATIF and does not replace the conversion or downstream validation contract below.

Protect the trace