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/lodash/_cloneBuffer.js

@@ -0,0 +1,35 @@
+var root = require('./_root');
+
+/** Detect free variable `exports`. */
+var freeExports = typeof exports == 'object' && exports && !exports.nodeType && exports;
+
+/** Detect free variable `module`. */
+var freeModule = freeExports && typeof module == 'object' && module && !module.nodeType && module;
+
+/** Detect the popular CommonJS extension `module.exports`. */
+var moduleExports = freeModule && freeModule.exports === freeExports;
+
+/** Built-in value references. */
+var Buffer = moduleExports ? root.Buffer : undefined,
+    allocUnsafe = Buffer ? Buffer.allocUnsafe : undefined;
+
+/**
+ * Creates a clone of  `buffer`.
+ *
+ * @private
+ * @param {Buffer} buffer The buffer to clone.
+ * @param {boolean} [isDeep] Specify a deep clone.
+ * @returns {Buffer} Returns the cloned buffer.
+ */
+function cloneBuffer(buffer, isDeep) {
+  if (isDeep) {
+    return buffer.slice();
+  }
+  var length = buffer.length,
+      result = allocUnsafe ? allocUnsafe(length) : new buffer.constructor(length);
+
+  buffer.copy(result);
+  return result;
+}
+
+module.exports = cloneBuffer;