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/wait-on/exampleConfig.js

@@ -0,0 +1,25 @@
+module.exports = {
+  // specify additional options here, especially http(s)
+  // see https://nodejs.org/api/tls.html#tls_tls_connect_options_callback for specifics
+  ca: [
+    /* strings or binaries */
+  ],
+  cert: [
+    /* strings or binaries */
+  ],
+  key: [
+    /* strings or binaries */
+  ],
+  passphrase: 'yourpassphrase',
+  auth: {
+    username: 'yourusername',
+    password: 'yourpassword'
+  },
+  strictSSL: false,
+  followRedirect: false,
+  headers: {
+    'x-custom': 'headers'
+  },
+  // optional default resources if not specified in command args
+  resources: ['http://foo/bar', 'http://cat/dog']
+};