~x-ai/grok-latest → B (2:3)

B improves production behavior with a real design fix (WEB_BROWSER_AGENT via delegate_opt instead of DSL body text) and correct next-pair logic (return None when sibling pool < 2 instead of silently falling back to all items), plus useful UX/route cleanup. A restores E2E auth with solid mock fixes (request body API, regex split, nil-safe token/state handling) but is test-infrastructure only, so it lands slightly less lasting product value despite being precise bugfixes.