fix(frame): keep reference-valued properties as IRIs

[simontaurus]

schemaToFrame emitted no subframe for reference-valued properties, on the assumption stated in the module header: a referenced IRI with no local triples stays { id: ... }. That assumption fails whenever the referenced node carries triples in the same graph.

Framing a Person schema whose works_for is declared {"type": "string", "format": "iri-reference"} against a graph where the employer has its own rdf:type and schema:name:

works_for: { id: 'https://example.org/acme', type: 'schema:Organization', name: 'ACME' }

An object where the schema requires a string, so the framed document fails the very schema the frame was derived from. OOLD-EXT-68fa already requires @embed: @never here, and the worked example in the specification's #framing section already prints it.

Reference signals: x-oold-range, an IRI-family format (the family OOLD-EXT-6ea3 recommends), or a term mapped "@type": "@id". Embedding wins where a property carries both.

keywordAliasKeys excludes keys that alias a JSON-LD keyword. id typically carries "format": "iri" and so matches the reference signals, but a subframe there writes { "@id": {...} }, which a processor rejects. The alias is searched through allOf because a dereferenced subclass chain keeps each superclass's context on its own member and the convention is declared by the base schema. The Python port caught this against the shared corpus.

Tests

First tests in this repo, run with npm test (node's built-in runner, no new dependency). Covering the specification's worked example, both-signals precedence, the keyword alias, and the round-trip above including an Ajv check that the framed output validates.

Removing only the @never line fails 3 of 5 with the expected messages, so they are not vacuous.

Paired with OO-LD/oold-python for the port. Refs OO-LD/oold-schema#160.