fix(analyze): cad_exists_in_db must require non-NULL geometry

Complements the NULL-geom 500 fix. cad_exists_in_db (docstring: "is there
GEOMETRY") checked only row existence, not geom IS NOT NULL — so for the ~964
meta-but-NULL-geom parcels it returned True. Consequence after the 500 fix:
such a parcel fell into the analyze fallback, find_or_enqueue_fetch step 2 saw
cad_exists_in_db=True → returned ("ready", None) → NO NSPD fetch enqueued →
analyze looped to a 202 with job_id=null and the parcel was stuck "fetching"
forever (never pulled real geometry, never resolved).

Fix: add `AND geom IS NOT NULL` to all three EXISTS branches (aligns the
function with its docstring). Now a NULL-geom parcel → cad_exists_in_db=False →
a real NSPD fetch is enqueued (202 + real job_id) → geometry populates →
re-poll → analyze succeeds (or 404 not_in_nspd if NSPD lacks it). No more
stuck-202. Valid-geom parcels unaffected. All 3 callers want geometry-presence
semantics. 37 analyze/fetch/by-bbox tests green. Refs #944.

backend/app/services/site_finder/cadastre_fetch.py

@@ -65,19 +65,28 @@ def validate_cad_format(cad_num: str) -> bool:
 
 
 def cad_exists_in_db(db: Session, cad_num: str) -> bool:
-    """Проверка: есть ли geometry для cad_num в любой из 3 таблиц.
+    """Проверка: есть ли НЕПУСТАЯ geometry для cad_num в любой из 3 таблиц.
 
     Использует EXISTS short-circuit — самая дешёвая проверка.
+
+    NB: `geom IS NOT NULL` обязателен — есть ~964 строк в cad_parcels_geom с meta,
+    но NULL-геометрией. Без фильтра функция врала бы «geometry есть» → analyze
+    fallback решал бы "ready"/не ставил NSPD-fetch → участок навсегда застревал в
+    202 (никогда не подтянул бы реальную геометрию). С фильтром null-geom участок
+    корректно идёт в fetch → НСПД отдаёт геометрию → analyze работает (или 404).
     """
     row = db.execute(
         text(
             """
             SELECT 1 WHERE EXISTS (
-                SELECT 1 FROM cad_quarters_geom g WHERE g.cad_number = :c
+                SELECT 1 FROM cad_quarters_geom g
+                 WHERE g.cad_number = :c AND g.geom IS NOT NULL
                 UNION ALL
-                SELECT 1 FROM cad_buildings b WHERE b.cad_num = :c
+                SELECT 1 FROM cad_buildings b
+                 WHERE b.cad_num = :c AND b.geom IS NOT NULL
                 UNION ALL
-                SELECT 1 FROM cad_parcels_geom p WHERE p.cad_num = :c
+                SELECT 1 FROM cad_parcels_geom p
+                 WHERE p.cad_num = :c AND p.geom IS NOT NULL
             ) LIMIT 1
             """
         ),