Finish the domain pipeline cleanup

docs/internal/pipeline.md

@@ -236,17 +236,17 @@ and terminal error text; failures before a candidate exists omit that payload.
 Only LLM calls made by the module operation belong to the module attempt.
 Validator calls retain independent scopes under `validate/` and are not
 duplicated into the module envelope. A failed terminal-envelope write is a
-framework error and is joined with any primary attempt error. Debug data is
-never used as a checkpoint source. Typed artifact debug envelopes are
-domain-neutral, redact sensitive metadata and bytes through the common debug
-policy, and record codec identity plus schema and content digests.
+non-retryable framework error and is joined with any primary attempt error.
+Debug data is never used as a checkpoint source. Typed artifact debug envelopes
+are domain-neutral, redact sensitive metadata and bytes through the common
+debug policy, and record codec identity plus schema and content digests.
 
 Merge and normalize attempts serialize their in-memory candidate with the
-codec's candidate encoder before typed validation. Serialized validators and
-attempt debug use that candidate representation, which carries the codec media
-type and schema identity but is never checkpointed or passed downstream. Only
-a validator-approved value is encoded through the strict final codec and made
-eligible for a checkpoint or stage output.
+codec's required candidate encoder before typed validation. Serialized
+validators and attempt debug use that candidate representation, which carries
+the codec media type and schema identity but is never checkpointed or passed
+downstream. Only a validator-approved value is encoded through the strict final
+codec and made eligible for a checkpoint or stage output.
 
 Checkpoint identity, physical layout, reuse behavior, and debug artifact
 handling are operator contracts in [Operations](../operations.md). Serialization