feat: add customer cart with expiry, shipping addresses with USPS validation, and multi-item PayPal checkout

frontend/src/api.ts

@@ -1,15 +1,9 @@
-export interface ItemImage {
-  id: number;
-  image_path: string;
-  sort_order: number;
-}
-
 export interface Item {
   id: number;
   name: string;
   description: string | null;
   price_cents: number;
-  images: ItemImage[];
+  images: { id: number; image_path: string; sort_order: number }[];
   status: 'available' | 'reserved' | 'sold';
 }
 
@@ -57,27 +51,3 @@ export async function markAvailable(id: number): Promise<Item> {
   const res = await fetch(`/api/admin/items/${id}/mark-available`, { method: 'POST' });
   return res.json();
 }
-
-export async function createPaypalOrder(itemId: number): Promise<string> {
-  const res = await fetch(`/api/checkout/paypal/${itemId}/create`, { method: 'POST' });
-  const data = await res.json();
-  if (!res.ok) throw new Error(data.error || 'Could not start checkout');
-  return data.orderID;
-}
-
-export async function capturePaypalOrder(itemId: number, orderID: string): Promise<void> {
-  const res = await fetch(`/api/checkout/paypal/${itemId}/capture`, {
-    method: 'POST',
-    headers: { 'Content-Type': 'application/json' },
-    body: JSON.stringify({ orderID })
-  });
-  if (!res.ok) throw new Error('Payment captured but confirmation failed — contact the seller.');
-}
-
-export async function demoPurchase(itemId: number): Promise<void> {
-  const res = await fetch(`/api/checkout/demo/${itemId}/purchase`, { method: 'POST' });
-  if (!res.ok) {
-    const data = await res.json().catch(() => ({}));
-    throw new Error(data.error || 'Demo purchase failed');
-  }
-}