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/get-uri/dist/ftp.d.ts

@@ -0,0 +1,14 @@
+/// <reference types="node" />
+import { AccessOptions } from 'basic-ftp';
+import { Readable } from 'stream';
+import { GetUriProtocol } from '.';
+export interface FTPReadable extends Readable {
+    lastModified?: Date;
+}
+export interface FTPOptions extends AccessOptions {
+    cache?: FTPReadable;
+}
+/**
+ * Returns a Readable stream from an "ftp:" URI.
+ */
+export declare const ftp: GetUriProtocol<FTPOptions>;