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/lodash/_cloneRegExp.js

@@ -0,0 +1,17 @@
+/** Used to match `RegExp` flags from their coerced string values. */
+var reFlags = /\w*$/;
+
+/**
+ * Creates a clone of `regexp`.
+ *
+ * @private
+ * @param {Object} regexp The regexp to clone.
+ * @returns {Object} Returns the cloned regexp.
+ */
+function cloneRegExp(regexp) {
+  var result = new regexp.constructor(regexp.source, reFlags.exec(regexp));
+  result.lastIndex = regexp.lastIndex;
+  return result;
+}
+
+module.exports = cloneRegExp;