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/axobject-query/lib/etc/objects/MenuItemCheckBoxRole.js

@@ -0,0 +1,17 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.default = void 0;
+var MenuItemCheckBoxRole = {
+  relatedConcepts: [{
+    module: 'ARIA',
+    concept: {
+      name: 'menuitemcheckbox'
+    }
+  }],
+  type: 'widget'
+};
+var _default = MenuItemCheckBoxRole;
+exports.default = _default;