~x-ai/grok-latest → B (2:1)

B’s split of forum into focused modules (nav, ingest, access, room_members, new_thread) plus shared new-thread compose logic is a lasting structural improvement to core server UI code, whereas A mainly upgrades the fixture/dev workflow (cargo-watch, persistent fixture-data/, preferred port) and a small room_page markup trim. B’s modularization outranks A’s useful but narrower tooling changes; the added sample-fixture helper is incidental.