fix: prevent asset conflicts between React and Grid.js versions

Add coexistence checks to all enqueue methods to prevent loading
both React and Grid.js assets simultaneously.

Changes:
- ReactAdmin.php: Only enqueue React assets when ?react=1
- Init.php: Skip Grid.js when React active on admin pages
- Form.php, Coupon.php, Access.php: Restore classic assets when ?react=0
- Customer.php, Product.php, License.php: Add coexistence checks

Now the toggle between Classic and React versions works correctly.

Co-authored-by: Claude Opus 4.7 <noreply@anthropic.com>

node_modules/@wordpress/components/build-module/guide/page-control.js

@@ -0,0 +1,35 @@
+import { createElement } from "react";
+/**
+ * WordPress dependencies
+ */
+import { __, sprintf } from '@wordpress/i18n';
+
+/**
+ * Internal dependencies
+ */
+import Button from '../button';
+import { PageControlIcon } from './icons';
+export default function PageControl({
+  currentPage,
+  numberOfPages,
+  setCurrentPage
+}) {
+  return createElement("ul", {
+    className: "components-guide__page-control",
+    "aria-label": __('Guide controls')
+  }, Array.from({
+    length: numberOfPages
+  }).map((_, page) => createElement("li", {
+    key: page
+    // Set aria-current="step" on the active page, see https://www.w3.org/TR/wai-aria-1.1/#aria-current
+    ,
+    "aria-current": page === currentPage ? 'step' : undefined
+  }, createElement(Button, {
+    key: page,
+    icon: createElement(PageControlIcon, null),
+    "aria-label": sprintf( /* translators: 1: current page number 2: total number of pages */
+    __('Page %1$d of %2$d'), page + 1, numberOfPages),
+    onClick: () => setCurrentPage(page)
+  }))));
+}
+//# sourceMappingURL=page-control.js.map