Add shared customer auth, cart handoff, and account dropdown.

Mirror Meshkee customer sessions onto the storefront, continue checkout on the customer dashboard, and show profile/orders/admin links under the header name.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/app/checkout/page.tsx

@@ -0,0 +1,18 @@
+import { Breadcrumb } from "@/components/ui/Breadcrumb";
+import { CheckoutPage } from "@/components/checkout/CheckoutPage";
+
+export default function CheckoutRoute() {
+  return (
+    <div className="mx-auto max-w-7xl px-4 py-10">
+      <Breadcrumb
+        items={[
+          { label: "خانه", href: "/" },
+          { label: "سبد خرید", href: "/checkout/cart" },
+          { label: "تسویه حساب" },
+        ]}
+      />
+      <h1 className="mb-6 text-2xl font-bold">تسویه حساب</h1>
+      <CheckoutPage />
+    </div>
+  );
+}