Measure observed electional rule tolerance in time and venue directions

Resolves one exact civil event instant, then walks outward through ten bounded samples in each earlier/later schedule direction and along each of eight venue bearings. Every selected electional criterion reports the last observed match, first observed failure, first unavailable sample, and traceable sample IDs. This is directional sampled evidence, not an exact boundary, continuous-time proof, monotonicity claim, whole-disk guarantee, recommendation, ranking, interpretation, prediction, or statistical confidence. 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.