Explain sampled electional feasibility and minimal observed rule relaxations

Evaluates the caller's existing electional predicates on a fixed 15, 30, or 60 minute UTC grid spanning at most seven days. It returns every sample's exact passed and failed criterion IDs, per-rule match/blocking ratios, every observed blocking signature, and inclusion-minimal failed-rule sets with witness samples. Minimal means set inclusion over observed evaluable samples; it does not recommend which rule to remove or assign weights. Unavailable geometry is explicit and excluded from feasibility. This is sampled evidence, not continuous-time proof, causal diagnosis, statistical confidence, interpretation, prediction, ranking, or advice. 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.