[ANierbeck]

Summary

sourcelume-registry #22 made GET /records/{id} on a VALIDATED TrainingProvenanceRecord resolve its trainingData references at read time: each entry carries the referenced dataset record's current status. That is the answer the demo exists for — the registry says "which datasets, in which state" instead of leaving the reader to resolve the references by hand.

This PR shows it in the demo:

• make query now asks for both records; the model record's answer lists trainingData with the dataset's recordStatus.
• make demo-atlas ends with the query, so the loop finishes on the registry's answer.
• While the Python plugin cannot publish the model record client-side, the query prints the exact direct publish call as a fallback instead of failing silently.
• README step 5 shows the response shape and states the read-time semantics (nothing stored on the model entity; a dataset published or corrected later shows up on the next read). The state table gains a row.

No record, schema or trainer change.

Testing

• Live against the Atlas stack and registry main (includes #22): published both records, make query shows the model record with trainingData carrying recordStatus: VALIDATED.
• Fallback path exercised with the registry absent: prints the direct publish call.
• No record changes; sample CI continues to validate both records against spec main.

Apache-ai: Yes
Generated-by: pi (claude-sonnet-5-5)
Reviewed-by: anierbeck