feat(distribution): 补齐退款加价回退、本站自卖与开通默认规则

退款时压缩卖方加价，人工/自动批次仅完结单可入账，号主收入进主站钱包；仲裁后重算释放并支持作废未入账 DS。开通时四种模式按默认生效，对外口径合并为 35/40/25，不再单独展示通道费。

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

backend/internal/modules/order/checkout_finalize.go

@@ -77,15 +77,11 @@ func appendCheckoutOwnerIncome(tx *gorm.DB, order *model.RentalOrder, settlement
 		return nil
 	}
 	orderID := order.ID
-	var siteID uint64
-	if order.DistributionSiteID != nil {
-		siteID = *order.DistributionSiteID
-	}
 	var ownerEntries []wallet.Entry
 	if settlement.OwnerRentIncomeCent > 0 {
 		ownerEntries = append(ownerEntries, wallet.Entry{
 			UserID:             order.OwnerID,
-			DistributionSiteID: siteID,
+			DistributionSiteID: 0,
 			OrderID:            &orderID,
 			Direction:          "in",
 			AmountCent:         settlement.OwnerRentIncomeCent,
@@ -98,7 +94,7 @@ func appendCheckoutOwnerIncome(tx *gorm.DB, order *model.RentalOrder, settlement
 	if settlement.DepositCompensationCent > 0 {
 		ownerEntries = append(ownerEntries, wallet.Entry{
 			UserID:             order.OwnerID,
-			DistributionSiteID: siteID,
+			DistributionSiteID: 0,
 			OrderID:            &orderID,
 			Direction:          "in",
 			AmountCent:         settlement.DepositCompensationCent,