Function: getEffectiveRenderBackend()
Returns the effective render backend for GenericViewport-based viewports: the configured 'gpu'/'cpu' pin, or the resolved 'auto' decision.
Pass override to resolve a per-mount renderBackend option with the same
precedence: 'gpu'/'cpu' pin the result, 'auto' resolves from capability
detection even when the global backend is pinned, and undefined falls back
to the global configuration.
Parameters
• override?: RenderBackend | "auto" | "gpu" | "cpu"