Add ticket system with QR scanner and PDF generation

- Add ticket validation and check-in API endpoints
- Add PDF ticket generation with QR codes (pdfkit)
- Add admin QR scanner page with camera support
- Add admin site settings page
- Update email templates with PDF ticket download link
- Add checked_in_by_admin_id field for audit tracking
- Update booking success page with ticket download
- Various UI improvements to events and booking pages

backend/src/lib/email.ts

@@ -548,6 +548,10 @@ export const emailService = {
     const locale = ticket.preferredLanguage || 'en';
     const eventTitle = locale === 'es' && event.titleEs ? event.titleEs : event.title;
     
+    // Generate ticket PDF URL
+    const apiUrl = process.env.API_URL || 'http://localhost:3001';
+    const ticketPdfUrl = `${apiUrl}/api/tickets/${ticket.id}/pdf`;
+    
     const attendeeFullName = `${ticket.attendeeFirstName} ${ticket.attendeeLastName || ''}`.trim();
     return this.sendTemplateEmail({
       templateSlug: 'booking-confirmation',
@@ -560,6 +564,7 @@ export const emailService = {
         attendeeEmail: ticket.attendeeEmail,
         ticketId: ticket.id,
         qrCode: ticket.qrCode || '',
+        ticketPdfUrl,
         eventTitle,
         eventDate: this.formatDate(event.startDatetime, locale),
         eventTime: this.formatTime(event.startDatetime, locale),