feat(site_finder): velocity coverage gap-fill via spatial+name fallback (#968 949-A)

For competitors missing from objective_complex_mapping, bridge to objective
velocity: nearest objective-bearing complex within 200m whose name tolerantly
matches → complex_id → objective_lots.project_name → objective_corpus_room_month.
Prod-measured: 148 → 329 mapped competitors (2.2×), validated by EXPLAIN+execute.

- nearest_cx CTE UNION'd into mapped (gap-fill only; primary 148 byte-identical,
  no double-count — UNION dedups, DISTINCT ON = one complex per competitor)
- candidates restricted to complexes WITH objective_lots.project_name (data-bearing):
  naive nearest-any gave +37; data-bearing nearest gives +181 (the real win)
- empty-comm_name guard avoids LIKE '%%' spatial-only leak
- velocity.py unchanged (its has_mapping coverage-gate is a separate concern);
  parcel.py unchanged (relevance_weight already satisfies DoD)

Blast radius narrow: affects relevance_weight (via stage_at_horizon) for
newly-mapped competitors; §22 market-pulse velocity (velocity.py) untouched.
deep-code-reviewer ⚠️ minor (approved); review items addressed. Part of EPIC #949.

backend/app/services/site_finder/competitors.py

@@ -41,6 +41,12 @@ _TIME_WINDOW_MONTHS: dict[str, float] = {
 # site_status значения, считающиеся «активными»
 _ACTIVE_STATUSES = frozenset({"sales", "construction"})
 
+# #968 (949-A): радиус спатиального матча domrf↔complexes для velocity gap-fill.
+# 200м + tolerant-name + nearest-per-domrf → подтверждаем «тот же ЖК» И гео, И
+# именем. Чистый name-match даёт ~40 cross-city false positives; чистый spatial
+# рискует приписать velocity СОСЕДНЕГО ЖК. Подбор по проду: 148 → ~300-400 (#968).
+_VELOCITY_MATCH_RADIUS_M: float = 200.0
+
 # ──────────────────────────────────────────────────────────────────────────────
 # #949 PR B (ТЗ §9.1, §16) — relevance_weight: детерминированная (без LLM)
 # взвешенная оценка релевантности конкурента 0..1 + explainability-breakdown.
@@ -287,10 +293,64 @@ _COMPETITORS_SQL = text("""
           AND longitude IS NOT NULL
         ORDER BY obj_id, snapshot_date DESC NULLS LAST
     ),
+    nearest_cx AS (
+        -- #968 (949-A) velocity gap-fill: для domrf-объектов, КОТОРЫХ НЕТ
+        -- в явном objective_complex_mapping, ищем «тот же ЖК» в complexes по
+        -- ГЕОГРАФИИ (≤ :velocity_match_radius_m м) И ТОЛЕРАНТНОМУ имени.
+        -- DISTINCT ON (obj_id) ORDER BY distance → ровно ОДИН (ближайший)
+        -- complex на конкурента: имя+гео подтверждают «тот же ЖК» (precision
+        -- важна — velocity питает forecast). Спатиальный join дёшев, т.к.
+        -- complexes мал (~1.5k строк с geom) — НЕ потому что latest_obj
+        -- пре-фильтрован (радиус участка применяется ниже, в финальном SELECT).
+        SELECT DISTINCT ON (o.obj_id)
+               o.obj_id,
+               c.id AS complex_id
+          FROM latest_obj o
+          JOIN complexes c
+            ON c.latitude IS NOT NULL
+           AND c.longitude IS NOT NULL
+           AND c.canonical_name IS NOT NULL
+           -- #968: только complexes, у которых ЕСТЬ objective velocity-данные →
+           -- «ближайший» выбирается среди data-bearing. Иначе ближайший complex
+           -- без objective_lots съедал бы матч (prod: +37 наивно → +181 так).
+           AND EXISTS (
+                   SELECT 1 FROM objective_lots ol
+                    WHERE ol.complex_id = c.id AND ol.project_name IS NOT NULL
+               )
+           AND ST_DWithin(
+                   ST_SetSRID(ST_MakePoint(o.longitude, o.latitude), 4326)::geography,
+                   ST_SetSRID(ST_MakePoint(c.longitude, c.latitude), 4326)::geography,
+                   CAST(:velocity_match_radius_m AS float)
+               )
+           AND (
+                   lower(btrim(o.comm_name)) = lower(btrim(c.canonical_name))
+                OR lower(btrim(c.canonical_name)) LIKE '%' || lower(btrim(o.comm_name)) || '%'
+                OR lower(btrim(o.comm_name)) LIKE '%' || lower(btrim(c.canonical_name)) || '%'
+               )
+         WHERE o.comm_name IS NOT NULL
+           AND btrim(o.comm_name) <> ''  -- иначе LIKE '%%' матчит всё → spatial-only
+           AND o.obj_id NOT IN (SELECT domrf_obj_id FROM objective_complex_mapping)
+         ORDER BY o.obj_id,
+                  ST_Distance(
+                      ST_SetSRID(ST_MakePoint(o.longitude, o.latitude), 4326)::geography,
+                      ST_SetSRID(ST_MakePoint(c.longitude, c.latitude), 4326)::geography
+                  ) ASC
+    ),
     mapped AS (
+        -- PRIMARY (unchanged): 148 явных маппингов — velocity для них byte-identical.
         SELECT cm.domrf_obj_id AS obj_id,
                cm.objective_complex_name
           FROM objective_complex_mapping cm
+        UNION
+        -- FALLBACK (gap-fill only): все project_name ОДНОГО ближайшего complex'а
+        -- (у комплекса может быть несколько корпус-project_name → velocity
+        -- легитимно суммируется по ним, но НЕ по нескольким комплексам).
+        SELECT nc.obj_id,
+               ol.project_name AS objective_complex_name
+          FROM nearest_cx nc
+          JOIN objective_lots ol
+            ON ol.complex_id = nc.complex_id
+           AND ol.project_name IS NOT NULL
     ),
     velocity AS (
         SELECT
@@ -433,6 +493,7 @@ def get_competitors(
                     "time_window_months": time_window_months,
                     "window_interval": window_interval,
                     "obj_class_filter": request.obj_class_filter,
+                    "velocity_match_radius_m": _VELOCITY_MATCH_RADIUS_M,
                 },
             )
             .mappings()