openai/gpt-chat-latest → B (3:2)

Side B introduces a substantial architectural shift from string-based subreddit scopes to a hierarchical `GlobalTree` keyed by canonical `ItemId`s, updating state management, event replay, URL parsing, voting, breadcrumbs, and persistence to support per-node rankings and navigation. Side A adds valuable Reddit-specific rendering (thumbnails, entity cards, image/link extraction, and tests), but it is primarily a presentation and metadata enhancement layered on top of the existing model, whereas B establishes broader lasting infrastructure used across the application.