Centralize legacy brush package import

src/legacy_brush_package_import_services.h

@@ -0,0 +1,17 @@
+#pragma once
+
+#include "app_core/brush_package_import.h"
+#include "foundation/result.h"
+
+#include <string_view>
+
+class App;
+
+namespace pp::panopainter {
+
+[[nodiscard]] pp::foundation::Status execute_legacy_brush_package_import(
+    App& app,
+    pp::app::BrushPackageImportKind kind,
+    std::string_view path);
+
+} // namespace pp::panopainter