Cart fixes (backend), adjusted header, added footer, mobile formatting updates

web/app/cart/page.js

@@ -85,6 +85,7 @@ export default function CartPage() {
     clearCart,
     applyCoupon,
     checkout,
+    cancelCheckout,
   } = useCart();
   const router = useRouter();
 
@@ -114,6 +115,14 @@ export default function CartPage() {
     }
   }, [cart]);
 
+  // If the cart arrives already locked (e.g. user closed the page mid-checkout)
+  // and there is no active Stripe session, release the lock automatically.
+  useEffect(() => {
+    if (cart?.checkoutPending && !clientSecret) {
+      cancelCheckout().catch(() => {});
+    }
+  }, [cart?.checkoutPending, clientSecret, cancelCheckout]);
+
   async function handleQuantityChange(cartItemId, newQty) {
     if (newQty < 1) {
       return;
@@ -351,7 +360,10 @@ export default function CartPage() {
                     setClientSecret(null);
                     setConfirmed(true);
                   }}
-                  onCancel={() => setClientSecret(null)}
+                  onCancel={async () => {
+                    await cancelCheckout().catch(() => {});
+                    setClientSecret(null);
+                  }}
                 />
               </Elements>
             )}