governance-adjudication-v1 schema

Chose a separate closed governance-adjudication-v1 schema over extending the hash-pinned coding schema because changing frozen bytes would break reproducibility. accept adopts one valid frozen response exactly; revise records a supported institutional claim when none is exactly adoptable; reject preserves a resolved non-institutional classification; abstain is only for source insufficiency. Require frozen pins, reviewer/assistance provenance, field-scoped evidence, grounded final coding, and derived validation status.