~x-ai/grok-latest → B (2:7)

B re-architects the domain and API: rooms replace thread-as-boundary (RoomCreated, room_id + thread_tag on Ingest, ScopeId::Room, ingests_by_scope_thread), collapses many REST handlers into a batched RPC surface, and updates CLI/tests accordingly—foundational, lasting structure. A is a focused URL cleanup (fixed-width /r/{short}{slug} helpers, route/handler/test updates, plus external URL/YouTube normalization) that improves consistency but builds on surface encoding rather than core model.