fix(site-finder): address PR #90 auto-review minor feedback

1. TS PipelineObject.distance_m — `number | null` для отражения defensive
   Python guard (`if obj.get("distance_m") is not None`). Comment объясняет
   почему.
2. Pipeline SQL: `text(f"...")` → `text("...")` + parameters. radius_m и
   horizon_months через `:param` placeholders + `cast(:horizon_months || ' months'
   AS interval)`. Consistency с остальными SQL в файле, plus защита от
   accidental injection при будущих изменениях.
3. top_objects: explicit field selection вместо `dict(r) for r in rows`.
   Раньше leak'ило все колонки из CTE `SELECT *` (latitude/longitude/
   snapshot_date/region_cd/dev_id) в API response. Теперь только nominated
   fields: obj_id, comm_name, dev_name, obj_class, flat_count, ready_dt,
   distance_m. Schema clean.

Per auto-review on 4e431bf.

backend/app/api/v1/parcels.py

@@ -415,21 +415,31 @@ def _aggregate_pipeline(rows: list[Any]) -> dict[str, Any]:
     # Sort quarters chronologically
     quarters_sorted = [{"quarter": k, **v} for k, v in sorted(by_quarter.items())]
 
-    # Top objects — по flat_count desc
-    top_objects = sorted(
-        [dict(r) for r in rows],
-        key=lambda r: r.get("flat_count") or 0,
-        reverse=True,
-    )[:PIPELINE_TOP_OBJECTS_LIMIT]
-
-    # Serialize date for JSON; distance_m — explicit None check, не falsy,
-    # потому что centroid-on-building даёт 0.0 (falsy) и raw Decimal упал бы
-    # в JSON serialization.
-    for obj in top_objects:
-        if obj.get("ready_dt"):
-            obj["ready_dt"] = obj["ready_dt"].isoformat()
-        if obj.get("distance_m") is not None:
-            obj["distance_m"] = round(float(obj["distance_m"]))
+    # Top objects — по flat_count desc.
+    # Explicit field selection вместо `dict(r)` — иначе CTE `SELECT *` протекает
+    # внутренние колонки (latitude/longitude/snapshot_date/region_cd/dev_id и т.д.)
+    # в API response. Не security issue, но schema-leak.
+    top_rows = sorted(rows, key=lambda r: r.get("flat_count") or 0, reverse=True)[
+        :PIPELINE_TOP_OBJECTS_LIMIT
+    ]
+    top_objects: list[dict[str, Any]] = []
+    for r in top_rows:
+        ready_dt = r.get("ready_dt")
+        distance_m = r.get("distance_m")
+        top_objects.append(
+            {
+                "obj_id": r["obj_id"],
+                "comm_name": r.get("comm_name"),
+                "dev_name": r.get("dev_name"),
+                "obj_class": r.get("obj_class"),
+                "flat_count": r.get("flat_count"),
+                # ISO date string для JSON; distance_m — explicit None guard
+                # (centroid-on-building даёт 0.0 — falsy float; raw Decimal иначе
+                # упадёт в JSON serialization).
+                "ready_dt": ready_dt.isoformat() if ready_dt else None,
+                "distance_m": round(float(distance_m)) if distance_m is not None else None,
+            }
+        )
 
     return {
         "objects_count": len(rows),
@@ -1159,7 +1169,7 @@ def analyze_parcel(
     # (latitude, longitude) — отдельный issue для database-expert.
     pipeline_rows = (
         db.execute(
-            text(f"""
+            text("""
             WITH latest_obj AS (
                 SELECT DISTINCT ON (obj_id) *
                   FROM domrf_kn_objects
@@ -1181,13 +1191,17 @@ def analyze_parcel(
              WHERE ST_DWithin(
                        ST_SetSRID(ST_MakePoint(o.longitude, o.latitude), 4326)::geography,
                        ST_Centroid(ST_GeomFromText(:wkt, 4326))::geography,
-                       {PIPELINE_RADIUS_M}
+                       :radius_m
                    )
                AND ready_dt >= CURRENT_DATE
-               AND ready_dt <  CURRENT_DATE + INTERVAL '{PIPELINE_HORIZON_MONTHS} months'
+               AND ready_dt <  CURRENT_DATE + cast(:horizon_months || ' months' AS interval)
              ORDER BY ready_dt ASC
         """),
-            {"wkt": geom_wkt},
+            {
+                "wkt": geom_wkt,
+                "radius_m": PIPELINE_RADIUS_M,
+                "horizon_months": str(PIPELINE_HORIZON_MONTHS),
+            },
         )
         .mappings()
         .all()

frontend/src/types/site-finder.ts

@@ -185,7 +185,10 @@ export interface PipelineObject {
   obj_class: string | null;
   flat_count: number | null;
   ready_dt: string | null;
-  distance_m: number;
+  // backend имеет explicit `is not None` guard для distance_m (centroid-on-
+  // building даёт 0.0 которое falsy, raw Decimal иначе упал бы в JSON), так
+  // что nullable отражает defensive Python path.
+  distance_m: number | null;
 }
 
 export interface Pipeline24mo {