Additive + optional fields for upcoming web features:
- analogs[]/actual_deals[] now carry lat/lon (radius comps ~100% covered, deals
100%) — were projected in SQL but discarded at the AnalogLot step.
- price_trend: monthly ₽/m² series (houses_price_dynamics → house_placement_history
fallback; 2347 houses covered, houses_price_dynamics empty in prod).
- last_scraped_at (absolute companion to data_freshness_minutes).
All nullable/graceful → zero risk to existing consumers. 237 estimator tests pass.
NOTE: price_trend/last_scraped_at computed on POST only (GET/{id} returns None) —
small follow-up if trend-on-reopen needed.
Refs #647#667
