Audit exact observation support and single-repair coverage loss

Extends the exact minimal-repair consequence hierarchy with support multiplicity. It partitions every recovered grid/sample observation by the complete set of distinct minimal repairs that admit it, reports exact per-repair exclusive and multiply supported counts, and certifies the union-coverage loss caused by removing each repair. It does not rank repairs or apply criterion weights. Results are exact for returned grid/sample observations, not continuous-time proofs, causal claims, quality scores, recommendations, interpretations, predictions, probabilities, 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.