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/fs-monkey/lib/correctPath.js

@@ -0,0 +1,43 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.correctPath = correctPath;
+exports.unixify = unixify;
+var isWin = process.platform === 'win32';
+function removeTrailingSeparator(str) {
+  var i = str.length - 1;
+  if (i < 2) {
+    return str;
+  }
+  while (isSeparator(str, i)) {
+    i--;
+  }
+  return str.substr(0, i + 1);
+}
+function isSeparator(str, i) {
+  var _char = str[i];
+  return i > 0 && (_char === '/' || isWin && _char === '\\');
+}
+function normalizePath(str, stripTrailing) {
+  if (typeof str !== 'string') {
+    throw new TypeError('expected a string');
+  }
+  str = str.replace(/[\\\/]+/g, '/');
+  if (stripTrailing !== false) {
+    str = removeTrailingSeparator(str);
+  }
+  return str;
+}
+function unixify(filepath) {
+  var stripTrailing = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : true;
+  if (isWin) {
+    filepath = normalizePath(filepath, stripTrailing);
+    return filepath.replace(/^([a-zA-Z]+:|\.\/)/, '');
+  }
+  return filepath;
+}
+function correctPath(filepath) {
+  return unixify(filepath.replace(/^\\\\\?\\.:\\/, '\\'));
+}