fix(hip-0025): show unresolved subchart batches in dag; hoist annotation keys

Address Copilot review on PR #32038:
- dag.go: printChild returned early for subcharts whose chart metadata is
  unavailable (storage-decoded charts at rollback/uninstall), hiding the
  structural resource-group batches buildStructuralLevel generates. Print
  an accurate note and still recurse into the structural child level. The
  old 'not found in chart dependencies' message was also misleading.
- sequencing.go: hoist HelmInternalSequencingAnnotations() out of the
  per-resource Visit closure so the slice is cloned once per batch.

pkg/action/sequencing.go

@@ -201,6 +201,7 @@ func (s *sequencedDeployment) applyBatch(ctx context.Context, batch sequence.Bat
 // resources before they are applied to Kubernetes. This prevents K8s API
 // validation errors for annotation keys that are not valid K8s label keys.
 func stripSequencingAnnotations(resources kube.ResourceList) error {
+	sequencingKeys := releaseutil.HelmInternalSequencingAnnotations()
 	return resources.Visit(func(info *resource.Info, err error) error {
 		if err != nil {
 			return err
@@ -214,7 +215,7 @@ func stripSequencingAnnotations(resources kube.ResourceList) error {
 			return nil
 		}
 		changed := false
-		for _, key := range releaseutil.HelmInternalSequencingAnnotations() {
+		for _, key := range sequencingKeys {
 			if _, exists := annotations[key]; exists {
 				delete(annotations, key)
 				changed = true

pkg/cmd/dag.go

@@ -194,8 +194,7 @@ func printSequencingDAG(chrt *chart.Chart, manifest string, out io.Writer) error
 
 		printChild := func(name string) {
 			if slices.Contains(level.Unresolved, name) {
-				fmt.Fprintf(out, "%s    (subchart %q not found in chart dependencies)\n", indent, name)
-				return
+				fmt.Fprintf(out, "%s    (subchart %q metadata unavailable; sequenced structurally from manifests)\n", indent, name)
 			}
 			if child := levelByPath[level.Path+"/charts/"+name]; child != nil {
 				printLevel(child)