Find every least-worst-regret repair-hardening profile

Extends the exact hardening-profile hierarchy with weight-free minimax regret across every analyzed simultaneous repair-failure budget. For each budget it returns the best observed avoided loss and every tied benchmark profile; for each profile it returns exact integer regret and witnesses, its worst regret, and every budget attaining it. All least-maximum-regret ties are returned. At most 70 profiles, four failure budgets, 280 profile-budget regret cells, and 19,600 benchmark references are admitted. Results are exact for returned sampled evidence and assign no budget probabilities, weights, floating-point scores, rankings, recommendations, interpretations, predictions, 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.