feat: 打手抢单大厅默认关闭假单展示，保留开关可恢复

通过 FAKE_GRAB_ORDER_POOL_ENABLED 控制，False 时仅返回真实订单，后台假单管理功能不变。

Co-authored-by: Cursor <cursoragent@cursor.com>

orders/views/dashou.py

@@ -97,12 +97,14 @@ class DashouDingdanHuoquView(APIView):
 
     def post(self, request):
         try:
+            from django.conf import settings
             from orders.services.fake_order_pool import (
                 dashou_should_use_fake_pool,
                 build_fake_order_pool_response,
             )
-            if dashou_should_use_fake_pool(request.user):
-                return build_fake_order_pool_response(request)
+            if getattr(settings, 'FAKE_GRAB_ORDER_POOL_ENABLED', False):
+                if dashou_should_use_fake_pool(request.user):
+                    return build_fake_order_pool_response(request)
 
             # 1. 获取请求参数
             data = request.data