Compare exact repair-hardening Pareto tradeoffs

Extends the single-repair hardening audit with a weight-free, exhaustive comparison of every protected-repair avoidance vector. Every pair is classified as equivalent, strictly dominated in one direction, or incomparable across the same zero-through-three exact repair-failure budgets. The response returns complete dominance certificates, equivalent hardening profiles, every undominated tie, and exact failure-budget witnesses for tradeoffs. At most 70 candidates, 2,415 pair relations, and 9,660 pair/budget comparisons are admitted. Results are exact for returned grid/sample evidence, not continuous-time guarantees, causal infrastructure claims, rankings, 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.