Move LLM validators to PromptKit prompt variables

docs/internal/validators.md

@@ -51,11 +51,15 @@ Decision cardinality is enforced: each candidate proposal must receive exactly o
 
 LLM validators:
 - build canonical validation request payloads;
-- batch using the [configured prompt budget](../config.md#concurrency);
-- call structured LLM client using response schema registry.
+- batch using `validation.max_prompt_tokens` and the existing domain token estimator;
+- select an embedded prompt ID and pass payload/description variables to the
+  role-bound structured client with the validator-decision schema.
 
 Oversized single proposals are rejected with `validator_input_too_large`.
-Malformed LLM validator responses are downgraded to warnings and rejected batch decisions.
+Exhausted structural repair becomes a warning and rejected batch decisions.
+Provider, malformed HTTP envelope, deadline, and admission failures propagate
+as runtime errors. Schema-valid decisions still undergo exact index/cardinality
+checks and domain acceptance without a semantic retry.
 
 ## Decision and Rejection Reporting