openai/gpt-chat-latest → A (4:1)

Side A makes a focused architectural simplification: it removes the now-redundant `ExpandNewThreadForm` UI action and server handler, and changes the home page to server-render `#new-thread-ui-slot` directly with the same compose/login state used on room pages. This eliminates duplicate interaction flow and dead code, whereas Side B is dominated by importing a very large parser subsystem and deleting a legacy file, adding substantial complexity whose lasting value is less certain despite the new demo UI and tests.