Introduce NEBULA_UNUSED macro in platform types and replace usages of UNREFERENCED_PARAMETER across multiple source files to standardize unused-parameter handling. Update various platform stubs (Linux window/host), CEF handlers, and Windows startup code to use NEBULA_UNUSED. Also adjust NebulaController::OnWindowCloseRequested to stop force-destroying the top-level window and rely on MaybeFinishShutdown once browsers report OnBeforeClose.
Andrew Zambazos
bbba5b2927