feat: implement multiple saved addresses with modal selector in checkout

- Add AddressController with full CRUD API for saved addresses
- Implement address management UI in My Account > Addresses
- Add modal-based address selector in checkout (Tokopedia-style)
- Hide checkout forms when saved address is selected
- Add search functionality in address modal
- Auto-select default addresses on page load
- Fix variable products to show 'Select Options' instead of 'Add to Cart'
- Add admin toggle for multiple addresses feature
- Clean up debug logs and fix TypeScript errors

customer-spa/src/pages/Account/Downloads.tsx

@@ -0,0 +1,15 @@
+import React from 'react';
+import { Download } from 'lucide-react';
+
+export default function Downloads() {
+  return (
+    <div>
+      <h1 className="text-2xl font-bold mb-6">Downloads</h1>
+      
+      <div className="text-center py-12">
+        <Download className="w-16 h-16 text-gray-300 mx-auto mb-4" />
+        <p className="text-gray-600">No downloads available</p>
+      </div>
+    </div>
+  );
+}