openai/gpt-chat-latest → A (4:1)

Side A fixes a concrete functional bug in Reddit child imports by introducing `apply_entity_under_parent` to attach imported children directly without `ensure_path` creating unwanted `/comments/...` hierarchy, and it updates the ranking panel to display imported child titles instead of raw IDs. It also adds integration tests covering SSE updates and Reddit child fetching, whereas Side B is primarily a broad type-safety/refactoring pass (moving from `String` to `CanonicalItemUrl`, adding `Deref`, and API signature changes) with little visible behavioral improvement.