Function render_plan 

pub fn render_plan(
    instance: &Instance,
    loaded: &Loaded,
    available: &AvailableKernels,
    mode: Mode,
    rows: u64,
    families: &Families,
) -> Result<String, LoadError>

2026-09-28: Fuse and render one plan of instance. 2026-10-02: each group line names the compute unit its kernels run on (venn::compute), from the target class’s kernel families, and each member node its pipeline; a node whose kernel declares another pipeline than the plan requires refuses the plan (pipeline::check_plan).