openai/gpt-chat-latest → B (9:1)

Side B implements a substantial architectural shift from flat subreddit scopes to a hierarchical `ItemId`/`GlobalTree` model, updating vote recording, event replay, URL parsing, UI navigation (breadcrumbs, entity panels, links), and persistence with new journal and tree infrastructure. Side A improves maintainability by replacing manually enumerated Kaocha test namespaces with automatic `^test\..+` discovery, but it is limited to test configuration rather than core project behavior or architecture.