~x-ai/grok-latest → B (1:5)

B re-architects the core model (rooms vs forum threads, ScopeId::Room, Ingest room_id/thread_tag) and replaces scattered REST handlers with a unified RPC batch surface plus CLI/tests, which is lasting platform design. A adds a useful POST /ui form-template and progressive thread-form morphing, but it is a UI convenience layered on existing web endpoints rather than structural backend change.