fix(invitation): 邀请返利改用实际结算利润并修正提号基准

backend/internal/modules/pickup/repository.go

@@ -308,8 +308,9 @@ func (r *Repository) Complete(ctx context.Context, pickupID uint64, req Complete
 		}
 
 		// 邀请返利：线下提号不走正常订单结账流程，必须在这里补发号主（卖家）侧返利，
-		// 否则号主邀请人永远拿不到提号产生的分成。基数按提号利润对半（与租赁订单卖家侧口径一致）。
-		if grossBasisCent := pickup.ProfitAmountCent; grossBasisCent > 0 {
+		// 否则号主邀请人永远拿不到提号产生的分成。
+		// 基准取「网站加价」与「线下利润」的较小值，避免按虚高的单一利润口径多算。
+		if grossBasisCent := pickupRebateGrossBasis(pickup.WebsiteProfitCent, pickup.ProfitAmountCent); grossBasisCent > 0 {
 			sellerSiteID := uint64(0)
 			if listing.DistributionSiteID != nil {
 				sellerSiteID = *listing.DistributionSiteID
@@ -1923,6 +1924,20 @@ func maxPickupCent(a, b int64) int64 {
 	return b
 }
 
+// pickupRebateGrossBasis 取网站加价与线下利润的较小值，负数按 0 处理。
+func pickupRebateGrossBasis(websiteProfitCent, offlineProfitCent int64) int64 {
+	if websiteProfitCent < 0 {
+		websiteProfitCent = 0
+	}
+	if offlineProfitCent < 0 {
+		offlineProfitCent = 0
+	}
+	if websiteProfitCent < offlineProfitCent {
+		return websiteProfitCent
+	}
+	return offlineProfitCent
+}
+
 func normalizePaging(page, pageSize int) (int, int) {
 	if page < 1 {
 		page = 1