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/scripts/config/jest-github-actions-reporter/index.js

@@ -0,0 +1,66 @@
+/**
+ * Based on https://github.com/facebook/jest/pull/11320.
+ *
+ * We might be able to remove this file once the Jest PR is merged, and a
+ * version of Jest that includes the GithubActionsReporter is released.
+ */
+
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+const newLine = /\n/g;
+const encodedNewLine = '%0A';
+const lineAndColumnInStackTrace = /^.*?:([0-9]+):([0-9]+).*$/;
+
+class GithubActionsReporter {
+	async onRunComplete( _contexts, _aggregatedResults ) {
+		if ( ! process.env.GITHUB_ACTIONS ) {
+			return;
+		}
+
+		if ( ! _aggregatedResults ) {
+			return;
+		}
+		const messages = getMessages( _aggregatedResults.testResults );
+
+		for ( const message of messages ) {
+			// eslint-disable-next-line no-console
+			console.log( message );
+		}
+	}
+}
+
+function getMessages( results ) {
+	if ( ! results ) {
+		return [];
+	}
+
+	return results.reduce(
+		flatMap( ( { testFilePath, testResults } ) =>
+			testResults
+				.filter( ( r ) => r.status === 'failed' )
+				.reduce(
+					flatMap( ( r ) => r.failureMessages ),
+					[]
+				)
+				.map( ( m ) => m.replace( newLine, encodedNewLine ) )
+				.map( ( m ) => lineAndColumnInStackTrace.exec( m ) )
+				.filter( ( m ) => m !== null )
+				.map(
+					( [ message, line, col ] ) =>
+						`::error file=${ testFilePath },line=${ line },col=${ col }::${ message }`
+				)
+		),
+		[]
+	);
+}
+
+function flatMap( fn ) {
+	return ( out, entry ) => out.concat( ...fn( entry ) );
+}
+
+module.exports = GithubActionsReporter;