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/defaults.js

@@ -0,0 +1,9 @@
+function _defaults(e, r) {
+  for (var t = Object.getOwnPropertyNames(r), o = 0; o < t.length; o++) {
+    var n = t[o],
+      a = Object.getOwnPropertyDescriptor(r, n);
+    a && a.configurable && void 0 === e[n] && Object.defineProperty(e, n, a);
+  }
+  return e;
+}
+module.exports = _defaults, module.exports.__esModule = true, module.exports["default"] = module.exports;