Function parse_auto_gpu 

pub(crate) fn parse_auto_gpu(value: &str) -> Option<Option<String>>

Parse an auto-GPU request (the CaptureSettings auto_gpu field, which selkies fills from –auto-gpu / SELKIES_AUTO_GPU). None = disabled; Some(None) = pick the first GPU overall (“true”); Some(Some(token)) = pick the first GPU whose kernel identity matches the case-insensitive token (vendor name, kernel driver name, devicetree vendor prefix, or raw PCI vendor id).