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/_arrayAggregator.js

@@ -0,0 +1,22 @@
+/**
+ * A specialized version of `baseAggregator` for arrays.
+ *
+ * @private
+ * @param {Array} [array] The array to iterate over.
+ * @param {Function} setter The function to set `accumulator` values.
+ * @param {Function} iteratee The iteratee to transform keys.
+ * @param {Object} accumulator The initial aggregated object.
+ * @returns {Function} Returns `accumulator`.
+ */
+function arrayAggregator(array, setter, iteratee, accumulator) {
+  var index = -1,
+      length = array == null ? 0 : array.length;
+
+  while (++index < length) {
+    var value = array[index];
+    setter(accumulator, value, iteratee(value), array);
+  }
+  return accumulator;
+}
+
+module.exports = arrayAggregator;