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/icons/build-module/library/drawer-left.js

@@ -0,0 +1,17 @@
+import { createElement } from "react";
+/**
+ * WordPress dependencies
+ */
+import { SVG, Path } from '@wordpress/primitives';
+const drawerLeft = createElement(SVG, {
+  width: "24",
+  height: "24",
+  xmlns: "http://www.w3.org/2000/svg",
+  viewBox: "0 0 24 24"
+}, createElement(Path, {
+  fillRule: "evenodd",
+  clipRule: "evenodd",
+  d: "M18 4H6c-1.1 0-2 .9-2 2v12c0 1.1.9 2 2 2h12c1.1 0 2-.9 2-2V6c0-1.1-.9-2-2-2zM8.5 18.5H6c-.3 0-.5-.2-.5-.5V6c0-.3.2-.5.5-.5h2.5v13zm10-.5c0 .3-.2.5-.5.5h-8v-13h8c.3 0 .5.2.5.5v12z"
+}));
+export default drawerLeft;
+//# sourceMappingURL=drawer-left.js.map