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/es-abstract/2025/IsArrayBufferViewOutOfBounds.js

@@ -0,0 +1,30 @@
+'use strict';
+
+var $TypeError = require('es-errors/type');
+
+var IsTypedArrayOutOfBounds = require('./IsTypedArrayOutOfBounds');
+var IsViewOutOfBounds = require('./IsViewOutOfBounds');
+var MakeDataViewWithBufferWitnessRecord = require('./MakeDataViewWithBufferWitnessRecord');
+var MakeTypedArrayWithBufferWitnessRecord = require('./MakeTypedArrayWithBufferWitnessRecord');
+
+var isDataView = require('is-data-view');
+var isTypedArray = require('is-typed-array');
+
+// https://262.ecma-international.org/15.0/#sec-isarraybufferviewoutofbounds
+
+module.exports = function IsArrayBufferViewOutOfBounds(O) {
+	var isDV = isDataView(O);
+	if (!isTypedArray(O) && !isDV) {
+		throw new $TypeError('Assertion failed: `O` must be a TypedArray or DataView');
+	}
+
+	if (isDV) { // step 1
+		var viewRecord = MakeDataViewWithBufferWitnessRecord(O, 'SEQ-CST'); // step 1.a
+
+		return IsViewOutOfBounds(viewRecord); // step 1.b
+	}
+
+	var taRecord = MakeTypedArrayWithBufferWitnessRecord(O, 'SEQ-CST'); // step 2
+
+	return IsTypedArrayOutOfBounds(taRecord); // step 3
+};