Function route_arms 

pub fn route_arms(
    circuit: &Circuit,
    set: (&[Rule], &[RuntimeRoute]),
    available: &AvailableKernels,
    policy: &Policy,
    primary: &FusionPlan,
) -> Result<Vec<(RuntimeRoute, FusionPlan)>, FuseError>

2026-09-30: The arm of each route in runtime that applies to mode at rows and plans differently from primary, fused with rules and available as the primary was.