Normalize ArifPay checkout payment URLs before returning.

Clean malformed provider paths (such as /checkout//{session_id}) so subscribe responses persist and return stable payment_url values.

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

internal/services/arifpay/service.go

@@ -8,6 +8,8 @@ import (
 	"fmt"
 	"io"
 	"net/http"
+	"net/url"
+	"path"
 	"strings"
 	"time"
 
@@ -167,7 +169,7 @@ func (s *ArifpayService) InitiateSubscriptionPayment(ctx context.Context, userID
 	}
 
 	sessionID := fmt.Sprintf("%v", data["sessionId"])
-	paymentURL := fmt.Sprintf("%v", data["paymentUrl"])
+	paymentURL := normalizeExternalURL(fmt.Sprintf("%v", data["paymentUrl"]))
 
 	// Update payment with session info
 	if err := s.paymentStore.UpdatePaymentSessionID(ctx, payment.ID, sessionID, paymentURL); err != nil {
@@ -184,6 +186,22 @@ func (s *ArifpayService) InitiateSubscriptionPayment(ctx context.Context, userID
 	}, nil
 }
 
+func normalizeExternalURL(raw string) string {
+	u, err := url.Parse(raw)
+	if err != nil {
+		return raw
+	}
+	if u.Path == "" {
+		return raw
+	}
+	cleaned := path.Clean(u.Path)
+	if strings.HasSuffix(u.Path, "/") && !strings.HasSuffix(cleaned, "/") {
+		cleaned += "/"
+	}
+	u.Path = cleaned
+	return u.String()
+}
+
 // ProcessPaymentWebhook handles the webhook callback from ArifPay
 func (s *ArifpayService) ProcessPaymentWebhook(ctx context.Context, req domain.WebhookRequest) error {
 	// ArifPay verify/webhook payloads are inconsistent: some responses include nonce, others only sessionId.