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

Side A fixes multiple real bugs across the request path (out-of-band delegate attribution, incorrect fallback that silently expanded the sibling pool, dead swap-side UI, and a route rename), touching rpc, ui_html, vote.rs, lib.rs and updating integration tests/browser tests consistently. Side B is a smaller, cosmetic-only change (color gradient normalization) with good test coverage but lower functional impact and narrower scope than A's cross-cutting correctness fixes.