feat: 总会员(包含式)模型、迁移、抢单校验与后台配置

- Huiyuan.is_bundle + club_huiyuan_bundle_include 表
- 购买/到期逻辑不变，抢单时总会员覆盖子会员类型
- dshyhq/clumber 返回 is_bundle 与 included_huiyuan_ids

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

products/models.py

@@ -150,6 +150,7 @@ class Huiyuan(QModel):
         blank=True,
         verbose_name='所属板块'
     )
+    is_bundle = models.BooleanField(default=False, verbose_name='是否为总会员(包含式)')
 
     class Meta:
         db_table = 'huiyuan'