openai/gpt-chat-latest → A (4:3)

Side A adds a reusable UI action architecture: a new `/ui` endpoint, `HtmlUiAction` parsing with JSON form-template substitution, shared `run_*` web handlers, and a `form_template` module with tests. Side B delivers substantial browser login, room routing, and cookie-based posting, but it also includes a large planning document and broad UI wiring; the more modular abstractions in A (shared handler extraction and generic form-template parsing) are likely to provide longer-term reuse across future UI features.