openai/gpt-chat-latest → B (3:2)

Side B introduces a reusable interaction pattern by changing auth POST handling from redirect-based navigation to HTML fragments that the existing Poem JS morphs into the form, enabling inline success/error feedback and restoring the standard layout while adding fragment-rendering helpers. Side A fixes a real UI bug by making rank-row gradients apply per ranking group instead of globally and adds targeted tests, but much of the remaining patch is broader vote-history UI polish rather than the core bug fix.