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/mousetrap/Gruntfile.js

@@ -0,0 +1,35 @@
+/*jshint node:true */
+module.exports = function(grunt) {
+    'use strict';
+
+    grunt.initConfig({
+        pkg: grunt.file.readJSON('package.json'),
+
+        complexity: {
+            options: {
+                errorsOnly: false,
+                cyclomatic: 10,
+                halstead: 30,
+                maintainability: 85
+            },
+            generic: {
+                src: [
+                    'mousetrap.js'
+                ]
+            },
+            plugins: {
+                src: [
+                    'plugins/**/*.js',
+                    '!plugins/**/tests/**',
+                    '!plugins/**/*.min.js'
+                ]
+            }
+        }
+    });
+
+    grunt.loadNpmTasks('grunt-complexity');
+
+    grunt.registerTask('default', [
+        'complexity'
+    ]);
+};