The type or namespace name Input.System does not exist

Issue description

The issue appears when opening the Unity editor or importing the SDK. The following error message is displayed:

Assets\Xsolla\Core\InputProxy\InputProxy.NewSystem.cs(5,19): error CS0234: The type or namespace name ‘Input.System’ does not exist in the namespace ‘Unity Engine’ (are you missing an assembly reference?)

The problem occurs because the Input System package is installed but not referenced in the xsolla.asmdef file.

Issue status: Can’t be fixed on the SDK side.

Workaround

1. Open Unity project.
2. Go to the Project panel and select the xsolla.asmdef file.
3. In the Inspector panel, go to the Assembly Definition References section.
4. Click the + icon and select Unity.InputSystem.