New /estimate/{id}/placement-history endpoint surfaces historical lots
from house_placement_history for the target house (linked after PR #527
bootstrap). Card hidden when no data.
- PlacementHistoryItem type added to trade-in.ts
- useEstimatePlacementHistory hook added to trade-in-api.ts
- PlacementHistoryCard component uses TanStack Query (no raw fetch)
- Wired into page.tsx after HouseInfoCard