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

Side B fixes a real concurrency bug (shared sentinel delegate blocking multi-user votes) with a proper type-level fix (Option<String>), adds a targeted regression test proving two distinct users can vote without collision, and updates related call sites/tests coherently. Side A adds a genuine security improvement (HTML sanitization) but the diff is dominated by a huge, uninteresting Cargo.lock dependency tree; the actual code change is small but valuable, while Side B's fix addresses a more fundamental correctness bug affecting core multi-user functionality with better test coverage.