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/axios/lib/platform/node/classes/FormData.js

@@ -0,0 +1,3 @@
+import FormData from 'form-data';
+
+export default FormData;

node_modules/axios/lib/platform/node/classes/URLSearchParams.js

@@ -0,0 +1,4 @@
+'use strict';
+
+import url from 'url';
+export default url.URLSearchParams;

node_modules/axios/lib/platform/node/index.js

@@ -0,0 +1,37 @@
+import crypto from 'crypto';
+import URLSearchParams from './classes/URLSearchParams.js';
+import FormData from './classes/FormData.js';
+
+const ALPHA = 'abcdefghijklmnopqrstuvwxyz';
+
+const DIGIT = '0123456789';
+
+const ALPHABET = {
+  DIGIT,
+  ALPHA,
+  ALPHA_DIGIT: ALPHA + ALPHA.toUpperCase() + DIGIT,
+};
+
+const generateString = (size = 16, alphabet = ALPHABET.ALPHA_DIGIT) => {
+  let str = '';
+  const { length } = alphabet;
+  const randomValues = new Uint32Array(size);
+  crypto.randomFillSync(randomValues);
+  for (let i = 0; i < size; i++) {
+    str += alphabet[randomValues[i] % length];
+  }
+
+  return str;
+};
+
+export default {
+  isNode: true,
+  classes: {
+    URLSearchParams,
+    FormData,
+    Blob: (typeof Blob !== 'undefined' && Blob) || null,
+  },
+  ALPHABET,
+  generateString,
+  protocols: ['http', 'https', 'file', 'data'],
+};