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/@babel/runtime/helpers/esm/asyncToGenerator.js

@@ -0,0 +1,26 @@
+function asyncGeneratorStep(n, t, e, r, o, a, c) {
+  try {
+    var i = n[a](c),
+      u = i.value;
+  } catch (n) {
+    return void e(n);
+  }
+  i.done ? t(u) : Promise.resolve(u).then(r, o);
+}
+function _asyncToGenerator(n) {
+  return function () {
+    var t = this,
+      e = arguments;
+    return new Promise(function (r, o) {
+      var a = n.apply(t, e);
+      function _next(n) {
+        asyncGeneratorStep(a, r, o, _next, _throw, "next", n);
+      }
+      function _throw(n) {
+        asyncGeneratorStep(a, r, o, _next, _throw, "throw", n);
+      }
+      _next(void 0);
+    });
+  };
+}
+export { _asyncToGenerator as default };