feat: Add new payment completion and failure routes, update donation handling in DonationForm and related components

frontend/src/views/PaymentCompleted.vue

@@ -52,12 +52,9 @@ const route = useRoute();
 const { t } = useI18n();
 
 function goBack() {
-  const returnUrl = route.query.returnUrl;
-  if (returnUrl) {
-    router.push(returnUrl);
-  } else {
-    router.back();
-  }
+  // Navigate back to the creator's page
+  const creatorName = route.params.creator?.split('/')[0] || '';
+  router.push(`/@${creatorName}`);
 }
 
 </script>