fix(geocode): set geocode_tried_at on successful geocode UPDATE

Add geocode_tried_at = NOW() to the success UPDATE SET clause so
successfully-geocoded listings record their attempt time, matching
the per-ID admin endpoint contract and the column spec.

tradein-mvp/backend/app/tasks/geocode_missing.py

@@ -182,12 +182,13 @@ async def geocode_missing_listings(
         precision: str | None = "city" if _geocode_is_coarse(geo) else None
 
         # UPDATE listings — PostGIS trigger (listings_set_geom_trg) обновит geom автоматически.
-        # geo_precision проставляется одновременно с координатами.
+        # geo_precision и geocode_tried_at проставляются одновременно с координатами.
         update_result = db.execute(
             text(
                 """
                 UPDATE listings
-                SET lat = :lat, lon = :lon, geo_precision = :precision
+                SET lat = :lat, lon = :lon, geo_precision = :precision,
+                    geocode_tried_at = NOW()
                 WHERE address = :addr AND lat IS NULL
                 """
             ),