perf: P1 性能优化批量修复 + kefu 视图拆分

P1 性能优化（避免循环内 N+1 / N 次 DB 查询）：
- shop_order_views._batch_images: 移除 ThreadPoolExecutor 掩盖的 N 次查询，改单次批量 + Python 侧分组
- product_query.DashouHuiyuanList: 5N 查询 -> 3 次批量预取 + 本地闭包判断
- roles.GetRolePermissionView / 用户列表: 循环内 RolePermission/Permission/UserRole/Role -> 批量 __in 预取
- guanli / zuzhang 杜次分红 4.2/4.3: 循环内 update_or_create + 单条 delete -> bulk_create + bulk_update + 批量 delete
- admin_config QQ 群配置: 循环内 exists/first/save/create -> 批量预取 + bulk_create + bulk_update
- jituan 服务层多处合并统计查询、批量预取 map
- rank 多处循环 N+1 改批量预取
- backend 多处循环内 count/create 改批量
- config/orders/merchant_ops 多处循环 N+1 改批量预取

其他改动：
- users/views/kefu.py 拆分为 kefu_base/kefu_dashou/kefu_orders/kefu_punishment/kefu_withdraw 5 个文件
- 删除遗留脚本 check_prod_uid.py / create_rbac_tables.sql

backend/views/kefu.py

@@ -342,6 +342,12 @@ class KefuGetDashouDetailView(APIView):
         member_records = Huiyuangoumai.query.filter(
             yonghu_id=uid
         ).order_by('-CreateTime')
+        # 批量预取会员信息
+        _huiyuan_ids = [r.huiyuan_id for r in member_records]
+        _huiyuan_map = {
+            h.huiyuan_id: h.jieshao
+            for h in Huiyuan.query.filter(huiyuan_id__in=_huiyuan_ids).only('huiyuan_id', 'jieshao')
+        }
         member_list = []
         for record in member_records:
             # 检查是否过期
@@ -351,11 +357,7 @@ class KefuGetDashouDetailView(APIView):
                 is_expired = record.daoqi_time < timezone.now() if record.daoqi_time else True
 
             if not is_expired:
-                try:
-                    huiyuan = Huiyuan.query.get(huiyuan_id=record.huiyuan_id)
-                    huiyuan_name = huiyuan.jieshao
-                except Huiyuan.DoesNotExist:
-                    huiyuan_name = '未知会员'
+                huiyuan_name = _huiyuan_map.get(record.huiyuan_id, '未知会员')
                 member_list.append({
                     'id': record.id,
                     'huiyuan_name': huiyuan_name,
@@ -828,8 +830,12 @@ class KefuGetShangjiaListView(APIView):
                 return Response({'code': 400, 'msg': '商家状态格式错误'})
 
         # 5. 统计总商家数（应用筛选后）
-        total = shangjia_qs.count()
-        valid_merchant_count = shangjia_qs.filter(zhuangtai=1).count()
+        _agg = shangjia_qs.aggregate(
+            total=Count('id'),
+            valid=Count('id', filter=Q(zhuangtai=1)),
+        )
+        total = _agg['total']
+        valid_merchant_count = _agg['valid']
 
         # 6. 分页
         offset = (page - 1) * page_size