Function plan_truing_experiment_v1 

pub fn plan_truing_experiment_v1(
    request: &TruingExperimentPlanRequestV1,
) -> Result<TruingExperimentPlanV1, TruingPlanErrorV1>

Recommend an exact-size set of observation ranges for MV/BC truing.

This function is deterministic for a fixed request. Every expensive trajectory/Jacobian evaluation happens once per unique valid candidate. Short-range or otherwise collinear facilities return an explicit MV-only plan, not a falsely precise BC recommendation.