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/@nodelib/fs.scandir/out/constants.js

@@ -0,0 +1,17 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.IS_SUPPORT_READDIR_WITH_FILE_TYPES = void 0;
+const NODE_PROCESS_VERSION_PARTS = process.versions.node.split('.');
+if (NODE_PROCESS_VERSION_PARTS[0] === undefined || NODE_PROCESS_VERSION_PARTS[1] === undefined) {
+    throw new Error(`Unexpected behavior. The 'process.versions.node' variable has invalid value: ${process.versions.node}`);
+}
+const MAJOR_VERSION = Number.parseInt(NODE_PROCESS_VERSION_PARTS[0], 10);
+const MINOR_VERSION = Number.parseInt(NODE_PROCESS_VERSION_PARTS[1], 10);
+const SUPPORTED_MAJOR_VERSION = 10;
+const SUPPORTED_MINOR_VERSION = 10;
+const IS_MATCHED_BY_MAJOR = MAJOR_VERSION > SUPPORTED_MAJOR_VERSION;
+const IS_MATCHED_BY_MAJOR_AND_MINOR = MAJOR_VERSION === SUPPORTED_MAJOR_VERSION && MINOR_VERSION >= SUPPORTED_MINOR_VERSION;
+/**
+ * IS `true` for Node.js 10.10 and greater.
+ */
+exports.IS_SUPPORT_READDIR_WITH_FILE_TYPES = IS_MATCHED_BY_MAJOR || IS_MATCHED_BY_MAJOR_AND_MINOR;