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/@jest/expect-utils/build/immutableUtils.js

@@ -0,0 +1,66 @@
+'use strict';
+
+Object.defineProperty(exports, '__esModule', {
+  value: true
+});
+exports.isImmutableList = isImmutableList;
+exports.isImmutableOrderedKeyed = isImmutableOrderedKeyed;
+exports.isImmutableOrderedSet = isImmutableOrderedSet;
+exports.isImmutableRecord = isImmutableRecord;
+exports.isImmutableUnorderedKeyed = isImmutableUnorderedKeyed;
+exports.isImmutableUnorderedSet = isImmutableUnorderedSet;
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ */
+
+// SENTINEL constants are from https://github.com/immutable-js/immutable-js/tree/main/src/predicates
+const IS_KEYED_SENTINEL = '@@__IMMUTABLE_KEYED__@@';
+const IS_SET_SENTINEL = '@@__IMMUTABLE_SET__@@';
+const IS_LIST_SENTINEL = '@@__IMMUTABLE_LIST__@@';
+const IS_ORDERED_SENTINEL = '@@__IMMUTABLE_ORDERED__@@';
+const IS_RECORD_SYMBOL = '@@__IMMUTABLE_RECORD__@@';
+function isObjectLiteral(source) {
+  return source != null && typeof source === 'object' && !Array.isArray(source);
+}
+function isImmutableUnorderedKeyed(source) {
+  return Boolean(
+    source &&
+      isObjectLiteral(source) &&
+      source[IS_KEYED_SENTINEL] &&
+      !source[IS_ORDERED_SENTINEL]
+  );
+}
+function isImmutableUnorderedSet(source) {
+  return Boolean(
+    source &&
+      isObjectLiteral(source) &&
+      source[IS_SET_SENTINEL] &&
+      !source[IS_ORDERED_SENTINEL]
+  );
+}
+function isImmutableList(source) {
+  return Boolean(source && isObjectLiteral(source) && source[IS_LIST_SENTINEL]);
+}
+function isImmutableOrderedKeyed(source) {
+  return Boolean(
+    source &&
+      isObjectLiteral(source) &&
+      source[IS_KEYED_SENTINEL] &&
+      source[IS_ORDERED_SENTINEL]
+  );
+}
+function isImmutableOrderedSet(source) {
+  return Boolean(
+    source &&
+      isObjectLiteral(source) &&
+      source[IS_SET_SENTINEL] &&
+      source[IS_ORDERED_SENTINEL]
+  );
+}
+function isImmutableRecord(source) {
+  return Boolean(source && isObjectLiteral(source) && source[IS_RECORD_SYMBOL]);
+}