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/@pmmmwh/react-refresh-webpack-plugin/lib/utils/getSocketIntegration.js

@@ -0,0 +1,30 @@
+/**
+ * Gets the socket integration to use for Webpack messages.
+ * @param {'wds' | 'whm' | 'wps' | string} integrationType A valid socket integration type or a path to a module.
+ * @returns {string} Path to the resolved socket integration module.
+ */
+function getSocketIntegration(integrationType) {
+  let resolvedSocketIntegration;
+  switch (integrationType) {
+    case 'wds': {
+      resolvedSocketIntegration = require.resolve('../../sockets/WDSSocket');
+      break;
+    }
+    case 'whm': {
+      resolvedSocketIntegration = require.resolve('../../sockets/WHMEventSource');
+      break;
+    }
+    case 'wps': {
+      resolvedSocketIntegration = require.resolve('../../sockets/WPSSocket');
+      break;
+    }
+    default: {
+      resolvedSocketIntegration = require.resolve(integrationType);
+      break;
+    }
+  }
+
+  return resolvedSocketIntegration;
+}
+
+module.exports = getSocketIntegration;