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/es/VisuallyHidden/VisuallyHidden.js

@@ -0,0 +1,39 @@
+import { _ as _objectWithoutPropertiesLoose, a as _objectSpread2 } from '../_rollupPluginBabelHelpers-1f0bf8c2.js';
+import { createComponent } from 'reakit-system/createComponent';
+import { createHook } from 'reakit-system/createHook';
+import 'reakit-utils/shallowEqual';
+import { useRole } from '../Role/Role.js';
+
+// Automatically generated
+var VISUALLY_HIDDEN_KEYS = [];
+
+var useVisuallyHidden = createHook({
+  name: "VisuallyHidden",
+  compose: useRole,
+  keys: VISUALLY_HIDDEN_KEYS,
+  useProps: function useProps(_, _ref) {
+    var htmlStyle = _ref.style,
+        htmlProps = _objectWithoutPropertiesLoose(_ref, ["style"]);
+
+    return _objectSpread2({
+      style: _objectSpread2({
+        border: 0,
+        clip: "rect(0 0 0 0)",
+        height: "1px",
+        margin: "-1px",
+        overflow: "hidden",
+        padding: 0,
+        position: "absolute",
+        whiteSpace: "nowrap",
+        width: "1px"
+      }, htmlStyle)
+    }, htmlProps);
+  }
+});
+var VisuallyHidden = createComponent({
+  as: "span",
+  memo: true,
+  useHook: useVisuallyHidden
+});
+
+export { VisuallyHidden, useVisuallyHidden };

node_modules/reakit/es/VisuallyHidden/index.js

@@ -0,0 +1,6 @@
+import '../_rollupPluginBabelHelpers-1f0bf8c2.js';
+import 'reakit-system/createComponent';
+import 'reakit-system/createHook';
+import 'reakit-utils/shallowEqual';
+import '../Role/Role.js';
+export { VisuallyHidden, useVisuallyHidden } from './VisuallyHidden.js';