Document Notarius cache reuse workflow

docs/internal/workspace.md

@@ -37,6 +37,12 @@ validates and renames the external bundle to the unique immutable Notarius
 bundle path supplied by `internal/artifacts`. Exact physical paths belong in
 [Operations](../operations.md#extraction-workflow).
 
+Prepared references delivered to Notarius use session-durable paths owned by
+`internal/artifacts` beneath
+`cache/notarius/references/<sha256>/<prepared-basename>`. These verified
+content-addressed snapshots are outside run-local layout, survive ordinary
+published-run cleanup, and are excluded from publish and restore enumeration.
+
 ## Locking
 
 `artifacts.LocalStore` enforces the single-writer session lock via an