~anthropic/claude-sonnet-latest → B (6:4)

Side B fixes a real concurrency bug (shared sentinel delegate causing 'delegate already bound' failures that silently blocked every human user after the first vote), with a targeted type-level fix (Option<String> for agent), removal of now-dead sentinel logic, and a concrete regression test proving multi-user voting works. Side A is a large infra/UI deployment commit (Dockerfile, fly.toml, dashboard, SSE audit feed) that adds real operational value but is mostly additive scaffolding and cosmetic dashboarding rather than fixing a functional defect.