3. Add URL-Valued Meta Fixtures

[MitchellShiell]

Add URL-valued properties to a subset of fields in the PCGL fixture so that the URL-to-hyperlink rendering behaviour of MetaValueRenderer can be demonstrated and tested. The added properties should represent realistic metadata that a data steward or dictionary admin would genuinely include, such as links to external ontology term definitions, standard specification pages, or field-level documentation.

Candidates for enrichment, based on existing field meta structure:

• Fields that already have a mappings.FHIR value could gain a mappings.FHIRSpec property linking to the relevant FHIR resource definition
• Fields with examples referencing ontology codes (e.g. MONDO identifiers) could gain a ontologyRef URL pointing to the term lookup page
• A small number of fields (five to ten across two or three schemas) is sufficient; the goal is coverage of the rendering behaviour, not comprehensive enrichment

The added properties must follow the same meta structure already present in the fixture and must not conflict with existing keys.

Why

No URL-valued meta properties currently exist in the PCGL fixture. Without them, the URL rendering branch of MetaValueRenderer (strings that are valid URLs becoming clickable hyperlinks) cannot be demonstrated in Storybook stories or exercised in realistic developer testing. This fixture work is a prerequisite for the Storybook story that covers URL rendering.

Acceptance Criteria

• At least five fields across at least two schemas have a URL-valued meta property added
• The added URLs are syntactically valid and point to real external resources relevant to the field's domain
• The new properties use key names that are consistent with the existing meta structure and would be recognisable to a data steward
• No existing meta properties are modified or removed
• The enrichment is documented with a brief comment or note in the fixture file indicating the convention used

Dependencies

None