feat: add payment management improvements and reminder emails

- Add option to approve/reject payments without sending notification emails
  (checkbox in review popup, default enabled)
- Add payment reminder email template and send functionality
- Track when reminder emails are sent (reminderSentAt field)
- Display reminder sent timestamp in payment review popup
- Make payment review popup scrollable for better UX
- Add payment-reminder template to email system (available in admin emails)

frontend/src/app/(public)/book/[eventId]/page.tsx

@@ -473,8 +473,8 @@ export default function BookingPage() {
     paymentMethods.push({
       id: 'tpago',
       icon: CreditCardIcon,
-      label: locale === 'es' ? 'TPago / Tarjeta Internacional' : 'TPago / International Card',
-      description: locale === 'es' ? 'Paga con tarjeta de crédito o débito' : 'Pay with credit or debit card',
+      label: locale === 'es' ? 'TPago / Tarjetas de Crédito' : 'TPago / Credit Cards',
+      description: locale === 'es' ? 'Pagá con tarjetas de crédito locales o internacionales' : 'Pay with local or international credit cards',
       badge: locale === 'es' ? 'Manual' : 'Manual',
     });
   }
@@ -483,8 +483,8 @@ export default function BookingPage() {
     paymentMethods.push({
       id: 'bank_transfer',
       icon: BuildingLibraryIcon,
-      label: locale === 'es' ? 'Transferencia Bancaria' : 'Bank Transfer',
-      description: locale === 'es' ? 'Transferencia bancaria local' : 'Local bank transfer',
+      label: locale === 'es' ? 'Transferencia Bancaria Local' : 'Local Bank Transfer',
+      description: locale === 'es' ? 'Pago por transferencia bancaria en Paraguay' : 'Pay via Paraguayan bank transfer',
       badge: locale === 'es' ? 'Manual' : 'Manual',
     });
   }