openai/gpt-chat-latest → A (4:1)

Side A changes the authentication flow to return HTML fragments for inline success/error handling, updates the shared Poem JS form interceptor to morph non-empty responses, factors the auth form into reusable markup, and removes redirect-based error handling. This is a lasting behavioral improvement that simplifies UX and infrastructure for form submissions, whereas Side B mainly removes a specialized UI action and redundant toolbar by server-rendering the existing collapsed compose state, a useful but narrower cleanup.