openai/gpt-chat-latest → B (4:1)

Side B implements a substantial cross-cutting feature: persistent theme selection via cookies and a POST /theme flow, preserves the theme across authentication by reissuing cookies, updates page rendering to honor the selected theme, and fixes room-aware URL generation throughout the RPC/API with dedicated helper functions and tests. Side A improves the rank list visualization by switching row coloring from list position to per-group score normalization and adds focused tests, but it is a localized UI enhancement compared with B's broader infrastructure and correctness improvements.