openai/gpt-chat-latest → B (4:1)

Side B fixes a core correctness issue in feed retrieval by anchoring implicit catch-up to durable ingest order instead of timestamps, preserving correct behavior across same-millisecond posts, clock rollback, and permission changes. It also refactors the feed logic into a shared helper, includes room metadata, and adds thorough integration tests covering multi-user visibility and revoked access, whereas Side A is largely deployment, monitoring, and operational infrastructure with only a few smaller correctness improvements (such as deduplicating Git object verification and authenticated Git fetches).