validate

# Validate Independently judge one exact subject against the acceptance in its existing bead or caller source, return one semantic result, and stop. Validate is the sole `verdict.v2` writer when persistence is requested. It never asks the model to reconstruct Plan or Candidate packets. ## Preconditions - The subject is a nonempty implementation candidate: the manifest lists at least one entry, and `store-verdict` refuses an empty one. Plans, audits, reviews, and other control artifacts are not completion subjects unless the caller explicitly requested document review. - The intent source is available as a caller-owned artifact or runtime-owned content-addressed snapshot; its acceptance digest is derived automatically. - The subject manifest still matches the subject. - Author and validator context IDs are explicit. - Freshness is explicitly attested with `source: runtime | caller` and an attester identity. Missing, colliding, or unattested identities produce `NOT_PROVEN`. This is a declared trust fact, not cryptographic proof that contexts were isolated. ## Cross-model fresh validator (caller-elected) A caller may request that the fresh validator run on a different model than the author. Dispatch via the controller-session recipe in the `agent-native` model-dispatch recipe (`codex-exec` and/or `ntm`, probed at runtime). Record author and validator `model_identity` in evidence refs and freshness attestation notes — do not change `verdict.v2` schema. If the requ...