Add per-quantity TPago payment links for multi-ticket checkout.

Each ticket quantity (1-5) can have its own TPago link so checkout, emails, and admin config use the correct fixed-amount URL.

backend/src/routes/tickets.ts

@@ -631,11 +631,21 @@ ticketsRouter.get('/:id', async (c) => {
     (db as any).select().from(payments).where(eq((payments as any).ticketId, id))
   );
   
+  // Count how many tickets belong to this booking (for per-quantity payment links)
+  let bookingTicketCount = 1;
+  if (ticket.bookingId) {
+    const bookingTickets = await dbAll<any>(
+      (db as any).select().from(tickets).where(eq((tickets as any).bookingId, ticket.bookingId))
+    );
+    bookingTicketCount = bookingTickets.length || 1;
+  }
+  
   return c.json({
     ticket: {
       ...ticket,
       event,
       payment,
+      bookingTicketCount,
     },
   });
 });