Function try_target_kernel 

pub fn try_target_kernel(
    gpu: &dyn GpuBackend,
    module: &str,
    func: &str,
) -> KernelHandle

2026-09-25: Look up a kernel from a module only some targets compile. Returns KernelHandle(0) without a lookup, and so without an audit row, when the backend does not carry module; otherwise it is try_kernel.