openai/gpt-chat-latest → B (3:2)

Side B adds an executable end-to-end browser test that seeds data, exercises the `/vote?pool=~/pool` flow through repeated vote/next-pair iterations, and verifies both edge-history updates and that displayed pairs remain within the requested pool, providing ongoing regression protection. Side A mostly introduces a detailed planning document plus a thin `RouteContext` wrapper around `ThreadNav` with re-exports, which establishes direction but does not yet change routing behavior or complete the refactor.