~x-ai/grok-latest → B (2:5)

B restores lasting product surface area: cookie sessions, /login|/logout, web POST ingest, public+private room/thread routes, compose forms, and ACL-gated room pages in forum.rs/auth/web_post. A is a real DSL grammar flip (explanation-first votes, parser split into block-prefixed vs item-definition paths) but most of the diff is cascading fixture/test/doc rewrites rather than new capability.