[HCA DCP] Add HCA projects to Google Datasets catalog

[NoopDog]

Add HCA DCP projects to the Google Dataset Search catalog so they're discoverable from Google. This is done by embedding schema.org Dataset JSON-LD on project detail pages — Google's crawler picks it up.

Companion to galaxyproject/brc-analytics#1264 (same approach, different catalog).

Reference implementation

NCPI Dataset Catalog has already shipped this for studies. Mirror their pattern:

• Builder + types: app/utils/schemaOrg.ts — SchemaDataset interface and buildStudyJsonLd() factory.
• Render component: app/components/Detail/components/StudyJsonLd/studyJsonLd.tsx — wraps the JSON-LD in a <script type="application/ld+json"> inside next/head, with HTML escaping to prevent script injection.
• Page integration: pages/[entityListType]/[...params].tsx — mounted on the detail route only.
• Tests: app/utils/schemaOrg.test.ts — covers required fields, truncation, and conditional fields.

Google Dataset required + recommended fields

Per Google's Dataset structured data guidelines:

Required

• name — descriptive title
• description — 50–5000 characters

Recommended

• identifier, url, sameAs
• creator, funder, license
• distribution (with contentUrl, encodingFormat)
• keywords, variableMeasured, measurementTechnique
• spatialCoverage, temporalCoverage
• includedInDataCatalog, isAccessibleForFree, version, citation

Initial mapping — HCA project (ProjectResponse) → Dataset

Source entity at app/apis/azul/hca-dcp/common/entities.ts (ProjectResponse).

schema.org field	Source / value
@context	"https://schema.org"
@type	"Dataset"
name	projectTitle (fall back to projectShortname)
description	projectDescription — strip HTML, truncate to 5000 chars (min 50)
identifier	[projectId, ...accessions] (HCA project UUID plus mapped INSDC/GEO/ArrayExpress accessions)
url	${browserURL}/projects/${projectId}
sameAs	Accession URLs (e.g. GEO, ArrayExpress, INSDC) derived from accessions
includedInDataCatalog	{ "@type": "DataCatalog", name: "Human Cell Atlas Data Coordination Platform", url: browserURL }
isAccessibleForFree	true
keywords	Union of genusSpecies, organ, organPart, disease, sampleEntityType, libraryConstructionApproach, etc.
creator	Map contributors → Person/Organization (name, affiliation, role)
funder	Map funding sources from projectResponse.funders if present
citation	Map publications → ScholarlyArticle (title, DOI/URL)
distribution	DataDownload[] from matrix files / contributed analyses with contentUrl + encodingFormat
variableMeasured	Optional PropertyValue[] derived from projectSummary (cell counts, donor counts, file counts, library construction approach)
license	TBD — confirm with team (HCA data use terms)

Open questions for funder / license / which file distributions to expose should be resolved before merge.

Implementation steps

1. Add app/utils/schemaOrg.ts (or HCA-namespaced equivalent) with SchemaDataset types and buildProjectJsonLd(project, browserURL).
2. Add a ProjectJsonLd component that renders the JSON-LD via next/head with the same HTML-escape helper as NCPI.
3. Mount the component on the project detail page (pages/projects/[entityId]).
4. Unit-test the builder: required fields present, description truncation, conditional fields omitted when source is null.
5. Validate output against Google's Rich Results Test and Schema Markup Validator for representative projects (single-cell, spatial, multi-organ).
6. Once shipped, request indexing via Google Search Console and confirm project pages start appearing in Google Dataset Search.

Out of scope (follow-ups)

• JSON-LD on samples/files detail pages.
• Sitemap entries for project detail pages if not already complete.