openai/gpt-chat-latest → A (4:1)

Side A fixes concrete Reddit import behavior by introducing `apply_entity_under_parent` to attach imported children without `ensure_path` creating unwanted `/comments` hierarchy, and updates the ranking panel to display imported child titles from the tree instead of fallback IDs. It also updates all call sites and adds integration tests covering SSE updates, child fetching, and the corrected UI, whereas Side B is a large initial Reddit-fetch implementation with infrastructure but less directly tied to a verified user-facing correctness fix.