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/@wordpress/components/build/utils/use-deprecated-props.js

@@ -0,0 +1,32 @@
+"use strict";
+
+var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault");
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.useDeprecated36pxDefaultSizeProp = useDeprecated36pxDefaultSizeProp;
+var _deprecated = _interopRequireDefault(require("@wordpress/deprecated"));
+/**
+ * WordPress dependencies
+ */
+
+function useDeprecated36pxDefaultSizeProp(props, /** The component identifier in dot notation, e.g. `wp.components.ComponentName`. */
+componentIdentifier, /** Version in which the prop was deprecated. */
+since = '6.3') {
+  const {
+    __next36pxDefaultSize,
+    __next40pxDefaultSize,
+    ...otherProps
+  } = props;
+  if (typeof __next36pxDefaultSize !== 'undefined') {
+    (0, _deprecated.default)('`__next36pxDefaultSize` prop in ' + componentIdentifier, {
+      alternative: '`__next40pxDefaultSize`',
+      since
+    });
+  }
+  return {
+    ...otherProps,
+    __next40pxDefaultSize: __next40pxDefaultSize !== null && __next40pxDefaultSize !== void 0 ? __next40pxDefaultSize : __next36pxDefaultSize
+  };
+}
+//# sourceMappingURL=use-deprecated-props.js.map