feat(订单): 实现推荐奖励系统支持佣金和赠送天数两种模式

重构推荐奖励处理逻辑，新增支持根据配置选择佣金奖励或赠送天数奖励
修改Discount相关字段类型为float64以支持小数折扣
添加GiftDays配置项控制赠送天数
新增FindActiveSubscribe方法查询用户有效订阅

internal/logic/public/order/getDiscount.go

@@ -3,7 +3,7 @@ package order
 import "github.com/perfect-panel/server/internal/types"
 
 func getDiscount(discounts []types.SubscribeDiscount, inputMonths int64) float64 {
-	var finalDiscount int64 = 100
+	var finalDiscount float64 = 1.0
 
 	for _, discount := range discounts {
 		if inputMonths >= discount.Quantity && discount.Discount < finalDiscount {
@@ -11,5 +11,5 @@ func getDiscount(discounts []types.SubscribeDiscount, inputMonths int64) float64
 		}
 	}
 
-	return float64(finalDiscount) / float64(100)
+	return finalDiscount
 }

internal/logic/public/portal/tool.go

@@ -7,14 +7,14 @@ import (
 )
 
 func getDiscount(discounts []types.SubscribeDiscount, inputMonths int64) float64 {
-	var finalDiscount int64 = 100
+	var finalDiscount float64 = 1.0
 
 	for _, discount := range discounts {
 		if inputMonths >= discount.Quantity && discount.Discount < finalDiscount {
 			finalDiscount = discount.Discount
 		}
 	}
-	return float64(finalDiscount) / float64(100)
+	return finalDiscount
 }
 
 func calculateCoupon(amount int64, couponInfo *coupon.Coupon) int64 {