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/reakit/lib/Form/utils/index.js

@@ -0,0 +1,17 @@
+'use strict';
+
+Object.defineProperty(exports, '__esModule', { value: true });
+
+require('../../_rollupPluginBabelHelpers-8f9a8751.js');
+var Form_utils_getIn = require('./getIn.js');
+require('reakit-utils/isObject');
+var Form_utils_setAllIn = require('./setAllIn.js');
+require('reakit-utils/toArray');
+require('reakit-utils/isInteger');
+var Form_utils_setIn = require('./setIn.js');
+
+
+
+exports.unstable_getIn = Form_utils_getIn.unstable_getIn;
+exports.unstable_setAllIn = Form_utils_setAllIn.unstable_setAllIn;
+exports.unstable_setIn = Form_utils_setIn.unstable_setIn;