openai/gpt-chat-latest → A (5:1)

Side A replaces a Reddit import placeholder with a complete background-fetch subsystem: it adds an async broker/worker, OAuth support, rate-limit handling, JSON parsing into EntityData, request deduplication/caching, integrates fetch triggering into application state and browse flow, and includes tests. Side B is a good correctness fix that moves the zero-ratio early return before ensure_item and voted_pairs insertion to prevent ghost items and stale voted pairs, but its scope and lasting impact are much smaller than the new functionality and infrastructure added in Side A.