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/dropdown/index.native.js

@@ -0,0 +1,64 @@
+import { createElement, Fragment } from "react";
+/**
+ * WordPress dependencies
+ */
+import { Component } from '@wordpress/element';
+class Dropdown extends Component {
+  constructor() {
+    super(...arguments);
+    this.toggle = this.toggle.bind(this);
+    this.close = this.close.bind(this);
+    this.state = {
+      isOpen: false
+    };
+  }
+  componentWillUnmount() {
+    const {
+      isOpen
+    } = this.state;
+    const {
+      onToggle
+    } = this.props;
+    if (isOpen && onToggle) {
+      onToggle(false);
+    }
+  }
+  componentDidUpdate(prevProps, prevState) {
+    const {
+      isOpen
+    } = this.state;
+    const {
+      onToggle
+    } = this.props;
+    if (prevState.isOpen !== isOpen && onToggle) {
+      onToggle(isOpen);
+    }
+  }
+  toggle() {
+    this.setState(state => ({
+      isOpen: !state.isOpen
+    }));
+  }
+  close() {
+    this.setState({
+      isOpen: false
+    });
+  }
+  render() {
+    const {
+      isOpen
+    } = this.state;
+    const {
+      renderContent,
+      renderToggle
+    } = this.props;
+    const args = {
+      isOpen,
+      onToggle: this.toggle,
+      onClose: this.close
+    };
+    return createElement(Fragment, null, renderToggle(args), isOpen && renderContent(args));
+  }
+}
+export default Dropdown;
+//# sourceMappingURL=index.native.js.map