openai/gpt-chat-latest → A (9:2)

Side A introduces a substantial architectural shift from flat subreddit-scoped rankings to a hierarchical ItemId-based tree, adding GlobalTree/NodeState, canonical URL parsing, breadcrumb navigation, journaled vote handling, and compatibility for replaying legacy events. Side B is mainly a UI refactor that reuses the existing entity section for vote comparison and switches DOM morph targets to item-specific selectors, which improves maintainability but is much narrower in lasting impact.