fix(tradein): sber series fallback continues on error + benchmark gated to ЕКБ region (#794 review)

tradein-mvp/backend/app/services/estimator.py

@@ -965,8 +965,8 @@ def _load_sber_index_series(db: Session, *, region: str) -> dict[date, float]:
                 .all()
             )
         except Exception as exc:
-            logger.warning("sber_price_index lookup failed (graceful, no-op): %s", exc)
+            logger.warning("sber_price_index lookup failed for %s (graceful): %s", dash, exc)
-            return {}
+            continue
         if rows:
             return {r["period_month"]: float(r["index_value_rub_m2"]) for r in rows}
     return {}

tradein-mvp/backend/app/services/sber_index.py

@@ -380,6 +380,9 @@ async def pull_sber_indices(
                             latest_month.isoformat(),
                             latest_val,
                         )
+                        # our listings median is ЕКБ-only →
+                        # compare only against Свердловская обл. (REF_AREA 66)
+                        if ref_area == "66":
                             # Task B: best-effort reconciliation to our scrape-median asking ppm²
                             try:
                                 our_median = db.execute(