Declarative JSON Schema per kind (segment/example/lemma/sop), embedded as real
.json artifacts (ADR-0006) and validated by a small hand-rolled interpreter
(properties/required/type/enum/additionalProperties + the `x-cph-content`
marker) — no jsonschema-crate churn for a one-optional-string scalar surface.
`x-cph-content: true` marks content fields (not in element.toml; require sibling
<field>.typ); everything else is an element.toml scalar. `validate(desc)` is
self-contained: UnknownKind for unknown kinds, MissingContentFile (path named in
message) for absent required .typ, SchemaViolation for bad scalars; lemma proof
optional ⇒ no diagnostic when absent. 8 tests green.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
