fix(admin): mount popover portal inside app container

Instead of mounting to body (which breaks scoped styles), we now
mount the popover portal to #woonoow-admin-app. This ensures
dropdowns inherit the correct CSS variables and styling.

admin-spa/src/routes/Orders/partials/OrderForm.tsx

@@ -530,7 +530,6 @@ export default function OrderForm({
                       onSearch={setSearchQ}
                       disabled={!itemsEditable}
                       showCheckIndicator={false}
-                      className="w-[200px] md:w-[300px]"
                     />
                   </div>
                 ) : (