Centralize legacy animation bridge

src/legacy_document_animation_services.h

@@ -0,0 +1,18 @@
+#pragma once
+
+#include "app_core/document_animation.h"
+#include "foundation/result.h"
+
+class Layer;
+class NodePanelAnimation;
+
+namespace pp::panopainter {
+
+class LegacyDocumentAnimationServices;
+
+[[nodiscard]] pp::foundation::Status execute_legacy_document_animation_plan(
+    NodePanelAnimation& panel,
+    const pp::app::DocumentAnimationOperationPlan& plan,
+    Layer* layer = nullptr);
+
+} // namespace pp::panopainter