fix: 修复订阅支付商品名前后缀不生效

backend/internal/service/payment_order.go

@@ -499,22 +499,39 @@ func selectedInstanceSupportedTypes(sel *payment.InstanceSelection) string {
 
 func (s *PaymentService) buildPaymentSubject(plan *dbent.SubscriptionPlan, limitAmount float64, cfg *PaymentConfig, sel *payment.InstanceSelection) string {
 	if plan != nil {
-		if plan.ProductName != "" {
-			return plan.ProductName
+		productName := plan.ProductName
+		if productName == "" {
+			productName = "Sub2API Subscription " + plan.Name
 		}
-		return "Sub2API Subscription " + plan.Name
+		return applyPaymentProductNameAffix(productName, cfg)
 	}
 	currency := payment.DefaultPaymentCurrency
 	if sel != nil {
 		currency = paymentProviderConfigCurrency(sel.ProviderKey, sel.Config)
 	}
 	amountStr := payment.FormatAmountForCurrency(limitAmount, currency)
+	if hasPaymentProductNameAffix(cfg) {
+		return applyPaymentProductNameAffix(amountStr, cfg)
+	}
+	return "Sub2API " + amountStr + " " + currency
+}
+
+func hasPaymentProductNameAffix(cfg *PaymentConfig) bool {
+	if cfg == nil {
+		return false
+	}
 	pf := strings.TrimSpace(cfg.ProductNamePrefix)
 	sf := strings.TrimSpace(cfg.ProductNameSuffix)
-	if pf != "" || sf != "" {
-		return strings.TrimSpace(pf + " " + amountStr + " " + sf)
+	return pf != "" || sf != ""
+}
+
+func applyPaymentProductNameAffix(productName string, cfg *PaymentConfig) string {
+	if !hasPaymentProductNameAffix(cfg) {
+		return productName
 	}
-	return "Sub2API " + amountStr + " " + currency
+	pf := strings.TrimSpace(cfg.ProductNamePrefix)
+	sf := strings.TrimSpace(cfg.ProductNameSuffix)
+	return strings.TrimSpace(pf + " " + productName + " " + sf)
 }
 
 func (s *PaymentService) maybeBuildWeChatOAuthRequiredResponse(ctx context.Context, req CreateOrderRequest, amount, payAmount, feeRate float64) (*CreateOrderResponse, error) {

backend/internal/service/payment_order_result_test.go

@@ -138,6 +138,41 @@ func TestCalculateCreateOrderPayAmountRejectsFractionalZeroDecimal(t *testing.T)
 	}
 }
 
+func TestBuildPaymentSubjectAppliesAffixToSubscriptionPlanProductName(t *testing.T) {
+	t.Parallel()
+
+	svc := &PaymentService{}
+	cfg := &PaymentConfig{
+		ProductNamePrefix: "PRE",
+		ProductNameSuffix: "SUF",
+	}
+	plan := &dbent.SubscriptionPlan{
+		Name:        "Pro Monthly",
+		ProductName: "Claude Pro",
+	}
+
+	got := svc.buildPaymentSubject(plan, 0, cfg, nil)
+	if got != "PRE Claude Pro SUF" {
+		t.Fatalf("buildPaymentSubject() = %q, want %q", got, "PRE Claude Pro SUF")
+	}
+}
+
+func TestBuildPaymentSubjectAppliesAffixToSubscriptionPlanDefaultName(t *testing.T) {
+	t.Parallel()
+
+	svc := &PaymentService{}
+	cfg := &PaymentConfig{
+		ProductNamePrefix: "PRE",
+		ProductNameSuffix: "SUF",
+	}
+	plan := &dbent.SubscriptionPlan{Name: "Team Monthly"}
+
+	got := svc.buildPaymentSubject(plan, 0, cfg, nil)
+	if got != "PRE Sub2API Subscription Team Monthly SUF" {
+		t.Fatalf("buildPaymentSubject() = %q, want %q", got, "PRE Sub2API Subscription Team Monthly SUF")
+	}
+}
+
 func TestMaybeBuildWeChatOAuthRequiredResponse(t *testing.T) {
 	t.Setenv("PAYMENT_RESUME_SIGNING_KEY", "0123456789abcdef0123456789abcdef")