修复(#85): 按数量匹配订阅促销价

Co-authored-by: multica-agent <github@multica.ai>

apis/types.api

@@ -229,6 +229,7 @@ type (
 		Quantity int64   `json:"quantity"`
 		Discount float64 `json:"discount"`
 		MapApple string  `json:"map_apple"`
+		Promo    *SubscribePromo `json:"promo"`
 	}
 	SubscribePromo {
 		RuleName   string `json:"rule_name"`
@@ -250,7 +251,6 @@ type (
 		UnitPrice         int64               `json:"unit_price"`
 		UnitTime          string              `json:"unit_time"`
 		Discount          []SubscribeDiscount `json:"discount"`
-		Promo             *SubscribePromo     `json:"promo"`
 		NodeCount         int64               `json:"node_count"`
 		Replacement       int64               `json:"replacement"`
 		Inventory         int64               `json:"inventory"`