Return total amount paid data for merch purchases, when available (#412)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **New Features**
* Ticket and merchandise entries now support an optional total paid
amount field for enhanced payment tracking.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: devksingh4

src/api/functions/tickets.ts

@@ -31,6 +31,7 @@ export type RawMerchEntry = {
   scanIsoTimestamp?: string;
   scannerEmail?: string;
   size: string;
+  total_paid?: number;
 };
 
 export async function getUserTicketingPurchases({
@@ -133,6 +134,7 @@ export async function getUserMerchPurchases({
       },
       refunded: item.refunded,
       fulfilled: item.fulfilled,
+      totalPaid: item.total_paid,
     });
   }
   return issuedTickets;

src/api/routes/tickets.ts

@@ -60,6 +60,7 @@ const ticketEntryZod = z.object({
   type: z.enum(["merch", "ticket"]),
   ticketId: z.string().min(1),
   purchaserData: purchaseSchema,
+  totalPaid: z.optional(z.number()),
 });
 
 const ticketInfoEntryZod = ticketEntryZod