Function bring_up 

pub fn bring_up(
    checkpoint: &Path,
    ctx: usize,
    out: &Path,
    targets: &[String],
) -> Result<Bringup, Refused>

Bring the checkpoint at checkpoint — a GGUF file, or a Hugging Face directory (config.json beside its safetensors) — up on the backends named in targets (every one when empty), over caches of ctx positions, each backend’s artifacts under out/<name>/ and the model’s program as out/program.lg: the spec read from the checkpoint’s own metadata (bring_up_spec).