Update site changes

frontend/src/app/(public)/events/[id]/EventDetailClient.tsx

@@ -186,11 +186,23 @@ export default function EventDetailClient({ eventId, initialEvent }: EventDetail
               </div>
               
               {canBook ? (
-                <Link href={`/book/${event.id}`}>
-                  <Button className="w-full" size="lg">
-                    {t('events.booking.join')}
-                  </Button>
-                </Link>
+                event.externalBookingEnabled && event.externalBookingUrl ? (
+                  <a
+                    href={event.externalBookingUrl}
+                    target="_blank"
+                    rel="noopener noreferrer"
+                  >
+                    <Button className="w-full" size="lg">
+                      {t('events.booking.join')}
+                    </Button>
+                  </a>
+                ) : (
+                  <Link href={`/book/${event.id}`}>
+                    <Button className="w-full" size="lg">
+                      {t('events.booking.join')}
+                    </Button>
+                  </Link>
+                )
               ) : (
                 <Button className="w-full" size="lg" disabled>
                   {isPastEvent