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/jsx-ast-utils/lib/values/expressions/ArrayExpression.js

@@ -0,0 +1,20 @@
+'use strict';
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.default = extractValueFromArrayExpression;
+/**
+ * Extractor function for an ArrayExpression type value node.
+ * An array expression is an expression with [] syntax.
+ *
+ * @returns - An array of the extracted elements.
+ */
+function extractValueFromArrayExpression(value) {
+  // eslint-disable-next-line global-require
+  var getValue = require('.').default;
+  return value.elements.map(function (element) {
+    if (element === null) return undefined;
+    return getValue(element);
+  });
+}