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/depd/lib/browser/index.js

@@ -0,0 +1,77 @@
+/*!
+ * depd
+ * Copyright(c) 2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = depd
+
+/**
+ * Create deprecate for namespace in caller.
+ */
+
+function depd (namespace) {
+  if (!namespace) {
+    throw new TypeError('argument namespace is required')
+  }
+
+  function deprecate (message) {
+    // no-op in browser
+  }
+
+  deprecate._file = undefined
+  deprecate._ignored = true
+  deprecate._namespace = namespace
+  deprecate._traced = false
+  deprecate._warned = Object.create(null)
+
+  deprecate.function = wrapfunction
+  deprecate.property = wrapproperty
+
+  return deprecate
+}
+
+/**
+ * Return a wrapped function in a deprecation message.
+ *
+ * This is a no-op version of the wrapper, which does nothing but call
+ * validation.
+ */
+
+function wrapfunction (fn, message) {
+  if (typeof fn !== 'function') {
+    throw new TypeError('argument fn must be a function')
+  }
+
+  return fn
+}
+
+/**
+ * Wrap property in a deprecation message.
+ *
+ * This is a no-op version of the wrapper, which does nothing but call
+ * validation.
+ */
+
+function wrapproperty (obj, prop, message) {
+  if (!obj || (typeof obj !== 'object' && typeof obj !== 'function')) {
+    throw new TypeError('argument obj must be object')
+  }
+
+  var descriptor = Object.getOwnPropertyDescriptor(obj, prop)
+
+  if (!descriptor) {
+    throw new TypeError('must call property on owner object')
+  }
+
+  if (!descriptor.configurable) {
+    throw new TypeError('property must be configurable')
+  }
+}