openai/gpt-chat-latest → A (9:1)

Commit A introduces substantial new functionality across the project. It adds server-backed theme selection with cookie persistence, updates many HTML handlers to propagate theme state, preserves theme cookies through authentication flows, adds a new POST /theme endpoint, replaces client-only theme switching with a server-integrated implementation, introduces room-aware URL generation helpers with tests, and updates many RPC responses and page renderers to produce correct room-specific links. The changes span authentication, routing, HTML rendering, RPC behavior, utilities, CSS, and documentation comments. Commit B is a focused refinement. It improves the garden UI by showing pairwise vote counts, changes the pinned-item HUD from a permalink into an unpin action, adds supporting CSS, a helper function with a unit test, updates browser tests, and makes a small documentation correction. These are useful UX and correctness improvements, but they are much narrower in scope and impact than the broad architectural and feature work in Commit A.