[s23b]

The examples gain an app for the genome tree's FHIR R4 output, the fhir leaf beside every place, change and copy.

• 12-fhir-view reads one of each kind of FHIR endpoint: the site Bundle at rs671, TAS2R38's gene Bundle and its change entries, UGT2B17's copy segment, and the haploid site at chrM 263. For each one it renders the Observations as tables of LOINC codes and values, and below them the leaf's own JSON, re-indented with its content and key order unchanged.
• Only rs671 is required. The two genes and the chrM site are optional grants, so the app also runs on the smaller fixture roots, and it reports anything ungranted or unanswered as absent. The public datasets grant tells a missing copy number upload apart from an empty answer.
• The report counts what it read and stays within the output cap, cutting long JSON with a count of what it left out.
• docs/03-data-paths.md adds fhir to the tree and a FHIR section: the profiles each endpoint follows, when a leaf is absent, why it carries no dates, how its IDs are derived, and its size limits.
• The fixtures gain the fhir leaves the app reads, byte for byte what an Ark serves for the same calls, plus the chrM 263 site.

The app ran on Ark Emulator against 1000 Genomes sample HG02953 with every slot filled. rs671 and chrM 263 read absent, since that sample has no genotype at either, and the TAS2R38 and UGT2B17 endpoints rendered with their real calls.

The fhir leaves need an ArkOS release that serves them. On earlier firmware every endpoint reads absent.