feat: send ticket receipts via WhatsApp and normalize phone numbers

Add WhatsApp API integration for automated receipt delivery
Enforce country codes for all phone number inputs (defaults to +60)

app/pages/confirmation/[token].vue

@@ -1,5 +1,5 @@
 <script lang="ts" setup>
-import type { PublicBooking } from '~~/shared/booking'
+import type { ConfirmBookingResponse, PublicBooking } from '~~/shared/booking'
 
 import {
   formatBookingCurrency,
@@ -85,7 +85,7 @@ async function confirmBooking() {
   confirming.value = true
 
   try {
-    const response = await apiClient<{ booking: PublicBooking, alreadyConfirmed: boolean }>(
+    const response = await apiClient<ConfirmBookingResponse>(
       `/api/public/bookings/${token}/confirm`,
       {
         method: 'POST'
@@ -98,8 +98,10 @@ async function confirmBooking() {
       title: response.alreadyConfirmed ? 'Booking already confirmed' : 'Booking confirmed',
       description: response.alreadyConfirmed
         ? 'This booking had already been confirmed earlier.'
-        : 'The booking details have been confirmed successfully.',
-      color: 'success',
+        : response.ticketReceiptWhatsApp.sent
+          ? `Ticket receipt was sent to ${response.ticketReceiptWhatsApp.recipientPhone}.`
+          : `Booking confirmed, but the ticket receipt WhatsApp was not sent: ${response.ticketReceiptWhatsApp.error}`,
+      color: response.alreadyConfirmed || response.ticketReceiptWhatsApp.sent ? 'success' : 'warning',
       icon: 'i-lucide-check-circle-2'
     })
   } catch (error) {