Retain validation report delivery errors in outcomes

docs/roadmap/remediation.md

@@ -57,6 +57,9 @@ architecture. The issues below affect behavior within the implemented structure.
 - R-04 complete: every help entry form finalizes report failures through the
   common diagnostic presentation path once.
 
+- R-05 complete: validation header/record write failures retain `DeliveryError`
+  separately from acquisition failures and combined diagnostic-stream failures.
+
 ## Findings and priority
 
 P1 means a supported invocation is blocked or its report content is corrupted.