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-haste-map/build/lib/getPlatformExtension.js

@@ -0,0 +1,30 @@
+'use strict';
+
+Object.defineProperty(exports, '__esModule', {
+  value: true
+});
+exports.default = getPlatformExtension;
+/**
+ * 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.
+ */
+
+const SUPPORTED_PLATFORM_EXTS = new Set(['android', 'ios', 'native', 'web']);
+
+// Extract platform extension: index.ios.js -> ios
+function getPlatformExtension(file, platforms) {
+  const last = file.lastIndexOf('.');
+  const secondToLast = file.lastIndexOf('.', last - 1);
+  if (secondToLast === -1) {
+    return null;
+  }
+  const platform = file.substring(secondToLast + 1, last);
+  // If an overriding platform array is passed, check that first
+
+  if (platforms && platforms.indexOf(platform) !== -1) {
+    return platform;
+  }
+  return SUPPORTED_PLATFORM_EXTS.has(platform) ? platform : null;
+}