openai/gpt-chat-latest → A (9:1)

Side A adds a substantial new Reddit API client with rate limiting, HTTP request handling, response/error processing, typed serde models, custom deserializers, and helper methods for working with posts and comments, introducing significant reusable functionality. Side B is a targeted cleanup that removes a redundant zero-ratio guard in the reducer and updates the test to reflect existing behavior where zero-weight edges are already skipped, which is a useful but much smaller maintenance improvement.