Fix: Safely access designJson properties in admin orders page

The admin orders page was trying to access .front.length and .back.length
without safely checking if they exist, causing 'Cannot read properties of
undefined' error. Now uses optional chaining and try-catch to handle parsing
errors gracefully.

src/app/admin/orders/page.tsx

@@ -95,8 +95,12 @@ export default async function OrdersPage({ searchParams }: { searchParams: { arc
         <div className="mt-8 divide-y divide-line border-t border-line">
           {orders.map((order) => {
             const hasPersonalised = order.items.some((item) => {
-              const design = JSON.parse(item.designJson) as { front: unknown[]; back: unknown[] };
-              return design.front.length > 0 || design.back.length > 0;
+              try {
+                const design = JSON.parse(item.designJson) as { front: unknown[]; back: unknown[] };
+                return (design.front?.length ?? 0) > 0 || (design.back?.length ?? 0) > 0;
+              } catch {
+                return false;
+              }
             });
             return (
               <div key={order.id} className="flex flex-wrap items-center gap-x-4 gap-y-2 py-4">