~x-ai/grok-latest → A (5:1)

A delivers lasting product surface: browser session cookies, web login/logout, /post ingest, and full private-room UI (ThreadNav, room pages, ACL-gated thread/post/expand views, compose forms) wired into routes and RPC. B only swaps choose-username redirects for fragment + Idiomorph morph and minor auth CSS—a narrow UX polish on one form.