openai/gpt-chat-latest → B (3:2)

Side B fixes a correctness issue in feed catch-up by anchoring implicit feeds to durable ingest order instead of timestamps, preventing missed posts when timestamps collide or move backwards, and preserving permission-aware behavior across private-room visibility changes. It also factors the logic into a reusable rpc_feed helper, adds room metadata to feed responses, and includes comprehensive multi-user integration tests covering concurrent ingests, permission revocation, and restoration, whereas Side A mixes one real bugfix for the external index with a larger feature/refactor for GitHub import cards and UI rendering.