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Merge tdd/vote-recast-guard: a re-cast no longer erases the record that a vote was delivered master

The outbound_votes upsert gains a SQL CASE defending exactly pending-over-delivered, under the conflict row lock — closing FOLLOWUPS re-cast race leg 1. The 17e recast fixture is re-pointed at the guard (turning its divergence oracle back on — the old precondition had been aborting it dark), the reseed poison-window cost is pinned where its only witnesses live, and ten documentation sites re-ground what delivered_state means. Reviewed by six streams plus four validators; fix wave applied; full tier and e2e green. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>