feat: add FHIR and MEDS public dataset interop worked examples

[edithatogo]

Summary

Add follow-on public dataset worked examples for MIMIC-IV Demo on FHIR and MIMIC-IV Demo in MEDS once the initial MIMIC-IV Demo acute example establishes the local-data and provenance pattern.

Linked Conductor track

conductor/tracks/public_clinical_dataset_worked_example_20260704

Why this is separate

FHIR and MEDS use different data models and are better suited to interoperability demonstrations than the first admitted-acute CSV workflow. They may identify reusable schema adapters, but should not expand the initial MIMIC acute track.

Acceptance criteria

• Assess FHIR and MEDS access, license, citations, file shapes, and field coverage.
• Define local-only data handling and fixture policy.
• Demonstrate conversion into the existing calculator/file contract or document the blockers.
• Preserve classification provenance and fail closed around Australian grouping claims.

Dependencies

• Public Clinical Dataset Worked Example discovery findings.
• Existing CLI/file and public calculator contracts.