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/eslint-module-utils/declaredScope.js

@@ -0,0 +1,13 @@
+'use strict';
+
+exports.__esModule = true;
+
+const { getScope } = require('./contextCompat');
+
+/** @type {import('./declaredScope').default} */
+exports.default = function declaredScope(context, name, node) {
+  const references = (node ? getScope(context, node) : context.getScope()).references;
+  const reference = references.find((x) => x.identifier.name === name);
+  if (!reference || !reference.resolved) { return undefined; }
+  return reference.resolved.scope.type;
+};