修复机构落地页构建失败并恢复 Polymarket 市场扫描

InstitutionalLandingPage.tsx 补充 "use client" 指令以通过 Next.js 15 构建。
polymarket_readonly.py 集成 WebSocket 报价缓存加速价格获取。
city_payloads.py 复用 Polymarket 层构建真实市场扫描数据替代空返回。

Constraint: 市场扫描需在无 Polymarket 价格 UI 的前提下提供数据
Tested: npm run build 通过

web/services/city_payloads.py

@@ -8,6 +8,26 @@ from web.core import _is_excluded_model_name
 
 TURKISH_MGM_CITIES = {"ankara", "istanbul"}
 
+_polymarket_layer = None
+
+
+def _get_polymarket_layer():
+    global _polymarket_layer
+    if _polymarket_layer is None:
+        from src.data_collection.polymarket_readonly import PolymarketReadOnlyLayer
+
+        _polymarket_layer = PolymarketReadOnlyLayer()
+    return _polymarket_layer
+
+
+def _top_probability_bucket(distribution: Any) -> Optional[Dict[str, Any]]:
+    if not isinstance(distribution, list):
+        return None
+    candidates = [row for row in distribution if isinstance(row, dict)]
+    if not candidates:
+        return None
+    return max(candidates, key=lambda row: float(row.get("probability") or -1.0))
+
 
 def build_city_summary_payload(data: Dict[str, Any]) -> Dict[str, Any]:
     return {
@@ -46,11 +66,41 @@ def build_city_market_scan_payload(
     requested_date = str(target_date or "").strip()
     selected_date = requested_date or local_date
 
-    return {
-        "market_scan": {"available": False},
-        "selected_date": selected_date,
-        "fetched_at": data.get("updated_at"),
-    }
+    try:
+        layer = _get_polymarket_layer()
+        probabilities = data.get("probabilities") or {}
+        distribution = probabilities.get("distribution") or []
+        top_bucket = _top_probability_bucket(distribution)
+        model_probability = (
+            float(top_bucket.get("probability"))
+            if (isinstance(top_bucket, dict) and top_bucket.get("probability") is not None)
+            else None
+        )
+
+        scan = layer.build_market_scan(
+            city=data.get("name"),
+            target_date=selected_date,
+            temperature_bucket=top_bucket,
+            model_probability=model_probability,
+            probability_distribution=distribution,
+            temp_symbol=str(data.get("temp_symbol") or ""),
+            forced_market_slug=market_slug,
+            include_related_buckets=not lite,
+            scan_filters=scan_filters,
+        )
+        return {
+            "market_scan": scan,
+            "selected_date": selected_date,
+            "fetched_at": data.get("updated_at"),
+        }
+    except Exception:
+        import traceback
+        traceback.print_exc()
+        return {
+            "market_scan": {"available": False},
+            "selected_date": selected_date,
+            "fetched_at": data.get("updated_at"),
+        }
 
 
 def build_city_detail_payload(