fix(velocity): cross-stack contract + NULL safety per pre-push review

3 pre-push code-reviewer findings fixed:

1. TS union extended ('objective'|'sale_graph'|'rosreestr_fallback')
   + UI conditions handle both objective и sale_graph как valid sources.
2. COALESCE(deals_total_vol_m2, deals_total_count * 45.0) — NULL safety
   for DKP-only rows (vol_m2 nullable, count > 0).
3. room_bucket parking filter — verified false positive (все 5 buckets
   apartments: студия/1/2/3/4+).

Refs: PR #157 pre-push code-reviewer

backend/app/services/site_finder/velocity.py

@@ -178,7 +178,8 @@ def compute_velocity(
                     )
                     SELECT
                         m.obj_id,
-                        SUM(crm.deals_total_vol_m2)     AS total_sqm,
+                        SUM(COALESCE(crm.deals_total_vol_m2,
+                                     crm.deals_total_count * 45.0)) AS total_sqm,
                         COUNT(DISTINCT crm.report_month) AS months_with_data,
                         MIN(crm.report_month)            AS period_start,
                         MAX(crm.report_month)            AS period_end
@@ -294,7 +295,8 @@ def _get_ekb_median(db: Session, months_window: int = 6) -> float | None:
                     WITH per_project AS (
                         SELECT
                             project_name,
-                            SUM(deals_total_vol_m2)     AS total_sqm,
+                            SUM(COALESCE(deals_total_vol_m2,
+                                         deals_total_count * 45.0)) AS total_sqm,
                             COUNT(DISTINCT report_month) AS months_data
                           FROM objective_corpus_room_month
                          WHERE report_month >= (CURRENT_DATE - :window_interval::interval)

frontend/src/app/analytics/recommend/page.tsx

@@ -260,16 +260,19 @@ export default function RecommendPage() {
                   }
                 />
                 <KpiCard
-                  label="Sale_graph покрытие"
+                  label="Покрытие velocity"
                   value={
+                    data.scope.velocity_source === "objective" ||
                     data.scope.velocity_source === "sale_graph"
                       ? `${data.scope.velocity_objects} ЖК`
                       : "fallback"
                   }
                   hint={
-                    data.scope.velocity_source === "sale_graph"
+                    data.scope.velocity_source === "objective"
-                      ? `${data.scope.velocity_observations} точек`
+                      ? `${data.scope.velocity_observations} точек · objective (свежее)`
-                      : "rosreestr city-wide"
+                      : data.scope.velocity_source === "sale_graph"
+                        ? `${data.scope.velocity_observations} точек · sale_graph`
+                        : "rosreestr city-wide"
                   }
                 />
                 <KpiCard

frontend/src/components/analytics/RecommendVelocityPanel.tsx

@@ -461,8 +461,9 @@ export function RecommendVelocityPanel({
         . Базовый темп{" "}
         <strong>{scope.market_velocity_per_month?.toFixed(1) ?? "—"}</strong>{" "}
         кв/мес (
-        {scope.velocity_source === "sale_graph"
+        {scope.velocity_source === "objective" ||
-          ? `sale_graph: ${scope.velocity_objects} ЖК / ${scope.velocity_observations} точек`
+        scope.velocity_source === "sale_graph"
+          ? `${scope.velocity_source}: ${scope.velocity_objects} ЖК / ${scope.velocity_observations} точек`
           : "fallback на rosreestr-сделки"}
         ),{" "}
         {scope.competitors_radius_n != null &&