~x-ai/grok-latest → B (2:5)

B establishes durable browse routing (`ItemId::browse_href` / `/~/…` paths, route wiring, parse fixes) and removes the whole theme cookie/endpoint/CSS fork in favor of one stylesheet—core navigation design. A is a solid, well-tested UX feature (CopyGardenRank + markdown formatter + UI/tests) but is incremental product surface on existing patterns, not structural lasting design.