refactor(bookings): simplify capacity tracking to use seats

Replace 'pax' booking mode with 'seat'
Consolidate inventory summary to track only seat counts
Update database schema and UI for seat-centric capacity

app/pages/seat/[token].vue

@@ -7,7 +7,6 @@ import {
   DINNER_EVENT_TITLE,
   DINNER_EVENT_VENUE,
   formatBookingCurrency,
-  getBookingModeLabel,
   getSeatLabel,
   getTicketCatalogItem
 } from '~~/shared/booking'
@@ -106,10 +105,10 @@ const totalFormatted = computed(() => formatBookingCurrency(receipt.value.bookin
             </div>
             <div class="rounded-2xl border border-default bg-elevated p-4">
               <p class="text-xs uppercase tracking-wide text-muted">
-                Booking Mode
+                Total Seats
               </p>
               <p class="mt-2 font-semibold text-highlighted">
-                {{ getBookingModeLabel(receipt.booking.bookingMode) }}
+                {{ receipt.booking.seatCount }} seats
               </p>
             </div>
             <div class="rounded-2xl border border-default bg-elevated p-4">