Find the smallest electional rule combinations that make a window infeasible

Evaluates one fixed 15-minute grid and all 30- and 60-minute phase projections, then returns every inclusion-minimal criterion subset with zero matching available samples. Every reported core includes an immediate-relaxation certificate for each member and one deterministic sample witness showing that deleting that member restores feasibility. The result is exact for the returned sampled grids, not a continuous-time proof, causal claim, quality score, recommendation, interpretation, prediction, probability, or statistical confidence. No licensed catalog, new dependency, or request-time network source is used. One standard quota unit per admitted request; failed or timed-out admitted attempts are not refunded. Do not automatically retry. Historical mode uses an explicit BCE/CE date object and UT1 conventions. Its response is the versioned historical envelope, not the modern UTC envelope. Read result for calculation fields and metadata for limits and uncertainty.