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/cliui/index.mjs

@@ -0,0 +1,13 @@
+// Bootstrap cliui with CommonJS dependencies:
+import { cliui } from './build/lib/index.js'
+import { wrap, stripAnsi } from './build/lib/string-utils.js'
+
+export default function ui (opts) {
+  return cliui(opts, {
+    stringWidth: (str) => {
+      return [...str].length
+    },
+    stripAnsi,
+    wrap
+  })
+}