openai/gpt-chat-latest → A (5:2)

Side A adds a durable cross-cutting feature by introducing server-backed theme persistence (cookie handling, POST /theme, layout integration, preserving the theme across authentication) and systematically propagating room-aware URLs through RPC responses with helper functions and tests. Side B fixes an important Reddit integration issue by requiring OAuth when configured, retrying after 401/403 with token refresh, and improving error handling, but it is a narrower subsystem-specific reliability improvement compared with A's broader architectural enhancements.