Document Notarius credential forwarding

docs/internal/adapters.md

@@ -65,6 +65,11 @@ Notarius is composed only when extraction is enabled; the extract stage owns
 prepared reference resolution, receipt, bundle, and configured-lane policy.
 The adapter validates the ordered selector/absolute-path pairs and is the sole
 owner of serializing them as repeated `--reference` arguments before `--json`.
+Its request may also carry one already-resolved opaque ConfigKit secret
+reference. Only the Notarius adapter reads that value, rejects an unresolved or
+empty programmatic reference, and maps the exact configured name/value into the
+shared subprocess override and sensitive-name fields. It never rereads the
+parent environment. A nil reference preserves the previous invocation.
 
 Application-owned object-store construction loads configured filesystem
 secrets before invoking the invocation's storage factory. Production commands