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/del/index.js

@@ -0,0 +1,70 @@
+'use strict';
+const path = require('path');
+const globby = require('globby');
+const isPathCwd = require('is-path-cwd');
+const isPathInCwd = require('is-path-in-cwd');
+const pify = require('pify');
+const rimraf = require('rimraf');
+const pMap = require('p-map');
+
+const rimrafP = pify(rimraf);
+
+function safeCheck(file) {
+	if (isPathCwd(file)) {
+		throw new Error('Cannot delete the current working directory. Can be overridden with the `force` option.');
+	}
+
+	if (!isPathInCwd(file)) {
+		throw new Error('Cannot delete files/folders outside the current working directory. Can be overridden with the `force` option.');
+	}
+}
+
+const del = (patterns, options) => {
+	options = Object.assign({}, options);
+
+	const {force, dryRun} = options;
+	delete options.force;
+	delete options.dryRun;
+
+	const mapper = file => {
+		if (!force) {
+			safeCheck(file);
+		}
+
+		file = path.resolve(options.cwd || '', file);
+
+		if (dryRun) {
+			return file;
+		}
+
+		return rimrafP(file, {glob: false}).then(() => file);
+	};
+
+	return globby(patterns, options).then(files => pMap(files, mapper, options));
+};
+
+module.exports = del;
+// TODO: Remove this for the next major release
+module.exports.default = del;
+
+module.exports.sync = (patterns, options) => {
+	options = Object.assign({}, options);
+
+	const {force, dryRun} = options;
+	delete options.force;
+	delete options.dryRun;
+
+	return globby.sync(patterns, options).map(file => {
+		if (!force) {
+			safeCheck(file);
+		}
+
+		file = path.resolve(options.cwd || '', file);
+
+		if (!dryRun) {
+			rimraf.sync(file, {glob: false});
+		}
+
+		return file;
+	});
+};