openai/gpt-chat-latest → A (3:2)

Side A implements two broadly useful, user-facing capabilities across the codebase: persistent theme selection via validated cookies and a dedicated /theme endpoint (including preserving the theme across login redirects), plus correct room-aware URL generation for RPC/API responses with new helper functions and tests. Side B adds explicit Reddit entity fetching with event-log persistence of raw payloads and replay support, which is substantial, but it is more specialized; Side A's changes affect core navigation, authentication, rendering, and link correctness throughout the application.