openai/gpt-chat-latest → B (4:1)

Side B changes application behavior by altering sibling navigation so each unranked sibling is rendered as its own navigation group instead of combining all unranked items into one group, and adds a focused regression test verifying the new grouping. Side A is primarily a refactor that consolidates duplicated test helpers into shared utilities and updates call sites, improving maintainability but leaving project functionality essentially unchanged.