feat(i18n): add multi-language support (en/zh) across app and server

Implement useLocale composable and shared translation dictionaries
Translate public pages, booking flow, and receipt views
Store booking locale to send localized WhatsApp notifications

server/utils/whatsapp.ts

@@ -26,6 +26,24 @@ export function buildWhatsAppDeepLink(phoneNumber: string, message: string) {
 export function buildBookingTicketReceiptMessage(event: H3Event, booking: PublicBooking) {
   const receiptUrl = buildAppUrl(event, `/receipt/${booking.receiptToken}`)
 
+  if (booking.locale === 'zh') {
+    return [
+      booking.event.title,
+      '',
+      `${booking.customerName} 您好，您的票券收据已确认。`,
+      '',
+      `收据：${receiptUrl}`,
+      `座位：${booking.seatCount}`,
+      `票券类别：${booking.ticketLabel || booking.ticketType.toUpperCase()}`,
+      `总价：${formatBookingCurrency(booking.totalPrice, booking.locale)}`,
+      `日期：${booking.event.dateLabel}`,
+      `时间：${booking.event.timeLabel}`,
+      `地点：${booking.event.venue}`,
+      '',
+      '请在活动当天出示收据中的二维码。'
+    ].join('\n')
+  }
+
   return [
     booking.event.title,
     '',
@@ -34,7 +52,7 @@ export function buildBookingTicketReceiptMessage(event: H3Event, booking: Public
     `Receipt: ${receiptUrl}`,
     `Seats: ${booking.seatCount}`,
     `Ticket Category: ${booking.ticketLabel || booking.ticketType.toUpperCase()}`,
-    `Total Price: ${formatBookingCurrency(booking.totalPrice)}`,
+    `Total Price: ${formatBookingCurrency(booking.totalPrice, booking.locale)}`,
     `Date: ${booking.event.dateLabel}`,
     `Time: ${booking.event.timeLabel}`,
     `Venue: ${booking.event.venue}`,