~x-ai/grok-latest → A (2:1)

A replaces brittle hand-enumerated kaocha suites with a single ^test\\..+ auto-discovery pattern, so new test namespaces run in CI and TEST.sh without further config edits—a small, lasting test-infra design fix. B improves local DX (cargo-watch, persistent fixture-data/, preferred port) and drops a bit of redundant room_page markup, but that value is mostly ergonomic tooling rather than project-wide correctness.