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/stylelint/lib/formatters/compactFormatter.js

@@ -0,0 +1,23 @@
+'use strict';
+
+const preprocessWarnings = require('./preprocessWarnings');
+
+/**
+ * @type {import('stylelint').Formatter}
+ */
+module.exports = function compactFormatter(results) {
+	return results
+		.flatMap((result) => {
+			const { warnings } = preprocessWarnings(result);
+
+			return warnings.map(
+				(warning) =>
+					`${result.source}: ` +
+					`line ${warning.line}, ` +
+					`col ${warning.column}, ` +
+					`${warning.severity} - ` +
+					`${warning.text}`,
+			);
+		})
+		.join('\n');
+};