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/express/lib/middleware/init.js

@@ -0,0 +1,43 @@
+/*!
+ * express
+ * Copyright(c) 2009-2013 TJ Holowaychuk
+ * Copyright(c) 2013 Roman Shtylman
+ * Copyright(c) 2014-2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict';
+
+/**
+ * Module dependencies.
+ * @private
+ */
+
+var setPrototypeOf = require('setprototypeof')
+
+/**
+ * Initialization middleware, exposing the
+ * request and response to each other, as well
+ * as defaulting the X-Powered-By header field.
+ *
+ * @param {Function} app
+ * @return {Function}
+ * @api private
+ */
+
+exports.init = function(app){
+  return function expressInit(req, res, next){
+    if (app.enabled('x-powered-by')) res.setHeader('X-Powered-By', 'Express');
+    req.res = res;
+    res.req = req;
+    req.next = next;
+
+    setPrototypeOf(req, app.request)
+    setPrototypeOf(res, app.response)
+
+    res.locals = res.locals || Object.create(null);
+
+    next();
+  };
+};
+

node_modules/express/lib/middleware/query.js

@@ -0,0 +1,47 @@
+/*!
+ * express
+ * Copyright(c) 2009-2013 TJ Holowaychuk
+ * Copyright(c) 2013 Roman Shtylman
+ * Copyright(c) 2014-2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict';
+
+/**
+ * Module dependencies.
+ */
+
+var merge = require('utils-merge')
+var parseUrl = require('parseurl');
+var qs = require('qs');
+
+/**
+ * @param {Object} options
+ * @return {Function}
+ * @api public
+ */
+
+module.exports = function query(options) {
+  var opts = merge({}, options)
+  var queryparse = qs.parse;
+
+  if (typeof options === 'function') {
+    queryparse = options;
+    opts = undefined;
+  }
+
+  if (opts !== undefined && opts.allowPrototypes === undefined) {
+    // back-compat for qs module
+    opts.allowPrototypes = true;
+  }
+
+  return function query(req, res, next){
+    if (!req.query) {
+      var val = parseUrl(req).query;
+      req.query = queryparse(val, opts);
+    }
+
+    next();
+  };
+};