RFC 089: link to the spec in catalogue-api instead of carrying a copy

[annak-k]

Preview

• Amended RFC 089 README

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Do not merge before catalogue-api#963. The new links point at catalogue-api/identifiers/spec, which does not exist on that repo's main until it lands. Left as a draft until then.

What does this change?

The last item on the scope of work for wellcomecollection/platform#6530: RFC 089 stops carrying its own copy of the spec and links to the canonical one instead.

The spec moved into catalogue-api with the implementation, so the API Gateway body can template it from the same repository and there is no second copy to keep in step. The two copies were byte-identical when the move happened, so nothing is lost here.

Removed from rfcs/089-identifiers-api/: openapi.yaml and openapi.md, plus the small uv project that rendered them (render_docs.py, pyproject.toml, uv.lock, .python-version, .gitignore). That validate-and-render step now runs on every pull request in catalogue-api instead of by hand here. RFC 088 keeps its own copy of the same tooling and is untouched.

No decisions change. README.md is all that remains in the directory, and the five cross-references to this RFC from rfcs/README.md, RFC 085 and RFC 091 all point at that file, so none of them break.

How to test

Read the amended "OpenAPI specification" section in the preview above, and follow the two links. validate_rfc.py and create_table_summary.py --check-readme both pass locally.