fix(recommend): cad_buildings.floors is INTEGER, not TEXT

PROD 500 on /api/v1/analytics/recommend/mix:
  psycopg.errors.UndefinedFunction: operator does not exist: integer ~ unknown
  LINE 19: AND ((cb.floors ~ '^[0-9]+$' AND cb.f...

_district_cadastre_baseline use regex \ on cb.floors. Schema is INTEGER
(verified information_schema), so the regex defence against text values
('1-2', '2-3' etc) is misplaced — simplify to floors >= 3 with NULL safety
via OR purpose ILIKE '%многокв%' fallback.

backend/app/services/analytics_queries.py

@@ -1349,10 +1349,9 @@ def _district_cadastre_baseline(db: Session, *, district_name: str) -> dict[str,
                      WHERE cb.cost_value IS NOT NULL
                        AND cb.area IS NOT NULL
                        AND cb.area >= 100
-                       -- floors хранится как TEXT (встречаются '1-2', '2-3') —
-                       -- считаем только чистые числа ≥3, либо purpose-fallback.
-                       AND ((cb.floors ~ '^[0-9]+$' AND cb.floors::int >= 3)
-                            OR cb.purpose ILIKE '%многокв%')
+                       -- floors INTEGER (Rosreestr ETL приводит к int); NULL = unknown.
+                       -- Считаем МКД если floors ≥3 или purpose содержит «многокв».
+                       AND (cb.floors >= 3 OR cb.purpose ILIKE '%многокв%')
                        AND (cb.cost_value / NULLIF(cb.area, 0))
                            BETWEEN 5000 AND 500000
                 )