fix: Add SALEOR_API_TOKEN auth for COD transaction creation

- Add SALEOR_API_TOKEN environment variable support
- Update Apollo client to include auth header
- Enable COD transaction creation after checkout

src/lib/saleor/client.ts

@@ -6,12 +6,13 @@ const httpLink = createHttpLink({
 });
 
 const authLink = setContext((_, { headers }) => {
-  // Saleor doesn't require auth for public queries
-  // Add auth token here if needed for admin operations
+  // Add auth token for admin operations
+  const token = process.env.SALEOR_API_TOKEN;
   return {
     headers: {
       ...headers,
       "Content-Type": "application/json",
+      ...(token && { "Authorization": `Bearer ${token}` }),
     },
   };
 });