Harden diagnostic handling and warning presentation

internal/framework/semanticreconcile/application.go

@@ -70,7 +70,7 @@ type ApplicationPolicy[T any] struct {
 }
 
 // GroupProvenance identifies the complete input contribution of one plan
-// group without prescribing domain warning or retry policy.
+// group without prescribing domain diagnostic or retry policy.
 type GroupProvenance struct {
 	memberPositions      []int
 	canonicalPosition    int
@@ -108,7 +108,7 @@ func (event AppliedGroup) Provenance() GroupProvenance {
 	return cloneGroupProvenance(event.provenance)
 }
 
-// RejectedGroup records a typed guard decision while leaving warning and retry
+// RejectedGroup records a typed guard decision while leaving diagnostic and retry
 // construction to the consuming domain.
 type RejectedGroup struct {
 	category   RejectionCategory