Remove legacy manifest provenance decoding

docs/roadmap/implementation.md

@@ -46,9 +46,11 @@ as base selection; do not add a persistent default selector or new precedence.
 
 Rename newly written informational provenance to overlay terminology, including
 `selected_overlay` in manifest configuration provenance. Do not add a dual-field
-reader, rewrite historical manifests, or introduce a manifest-version rejection
-solely for this informational rename. Existing generic decoding behavior applies
-to old optional provenance; it does not become resume authority. Preserve
+reader, automatically rewrite historical manifests, or introduce a manifest-version
+rejection solely for this informational rename. Existing strict typed decoding
+rejects retired provenance fields. Document backed-up operator migration of
+that informational member without changing execution/checkpoint state; it does
+not become resume authority. Preserve
 semantic fingerprints and effective-value digest rules when values are unchanged.
 
 Only Narratio pipeline configuration selection is renamed. Keep model/profile
@@ -199,8 +201,9 @@ config commands in `internal/app/`; configuration provenance in
    directory is not a discovery fallback. Do not freeze incidental error wording.
 5. Verify unchanged effective values retain digest and stage-reuse behavior;
    only diagnostic source labels/paths and selected provenance terminology change.
-   Test loading representative existing manifests without inventing a new
-   invalidation or rejection gate for old optional selection metadata.
+   Test current provenance round trips and strict rejection of unknown/retired
+   provenance fields. Document deliberate operator migration; do not add a
+   compatibility decoder, semantic invalidation rule, or schema-version gate.
 6. Run focused and full tests before proceeding so failures from the dependency
    and terminology change are separated from adapter migrations. No Audita or
    Notarius credential/CLI behavior changes in this stage.