Function kernel_status 

pub fn kernel_status(
    device: &Device,
    class: &ClassInfo,
    sources: &ClassSources,
    guards: &[Guard],
    k: &KernelId,
) -> (Result<(), Absence>, Option<Instr>)

2026-09-30: Whether device can run kernel k from sources of class, and the instruction kind its source guard needs (None: unguarded or not compiled).