Finalize artifact workflow documentation

internal/adapters/subprocess/doc.go

@@ -1,3 +1,2 @@
 // Package subprocess provides reusable process execution and generated-config helpers.
 package subprocess
-

internal/app/run_control.go

@@ -35,7 +35,8 @@ type priorStageOutcome struct {
 }
 
 func decideStageAction(s stage.Stage, m *manifest.Manifest, force bool) stageAction {
-	// TODO: incorporate stale detection once checksum/input change tracking is implemented.
+	// A succeeded aggregate record is the initial skip candidate. The runner and
+	// planner then let stage-owned resume validation refine that decision.
 	if !force && stageSucceeded(m, s.Name()) {
 		return stageActionSkip
 	}