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/spacer/component.js

@@ -0,0 +1,47 @@
+import { createElement } from "react";
+/**
+ * External dependencies
+ */
+
+/**
+ * Internal dependencies
+ */
+
+import { contextConnect } from '../context';
+import { View } from '../view';
+import { useSpacer } from './hook';
+function UnconnectedSpacer(props, forwardedRef) {
+  const spacerProps = useSpacer(props);
+  return createElement(View, {
+    ...spacerProps,
+    ref: forwardedRef
+  });
+}
+
+/**
+ * `Spacer` is a primitive layout component that providers inner (`padding`) or outer (`margin`) space in-between components. It can also be used to adaptively provide space within an `HStack` or `VStack`.
+ *
+ * `Spacer` comes with a bunch of shorthand props to adjust `margin` and `padding`. The values of these props
+ * can either be a number (which will act as a multiplier to the library's grid system base of 4px),
+ * or a literal CSS value string.
+ *
+ * ```jsx
+ * import { Spacer } from `@wordpress/components`
+ *
+ * function Example() {
+ *   return (
+ *     <View>
+ *       <Spacer>
+ *         <Heading>WordPress.org</Heading>
+ *       </Spacer>
+ *       <Text>
+ *         Code is Poetry
+ *       </Text>
+ *     </View>
+ *   );
+ * }
+ * ```
+ */
+export const Spacer = contextConnect(UnconnectedSpacer, 'Spacer');
+export default Spacer;
+//# sourceMappingURL=component.js.map