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/adapters/fs.d.ts

@@ -0,0 +1,20 @@
+import type * as fsStat from '@nodelib/fs.stat';
+import type { Dirent, ErrnoException } from '../types';
+export interface ReaddirAsynchronousMethod {
+    (filepath: string, options: {
+        withFileTypes: true;
+    }, callback: (error: ErrnoException | null, files: Dirent[]) => void): void;
+    (filepath: string, callback: (error: ErrnoException | null, files: string[]) => void): void;
+}
+export interface ReaddirSynchronousMethod {
+    (filepath: string, options: {
+        withFileTypes: true;
+    }): Dirent[];
+    (filepath: string): string[];
+}
+export declare type FileSystemAdapter = fsStat.FileSystemAdapter & {
+    readdir: ReaddirAsynchronousMethod;
+    readdirSync: ReaddirSynchronousMethod;
+};
+export declare const FILE_SYSTEM_ADAPTER: FileSystemAdapter;
+export declare function createFileSystemAdapter(fsMethods?: Partial<FileSystemAdapter>): FileSystemAdapter;

node_modules/@nodelib/fs.scandir/out/adapters/fs.js

@@ -0,0 +1,19 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.createFileSystemAdapter = exports.FILE_SYSTEM_ADAPTER = void 0;
+const fs = require("fs");
+exports.FILE_SYSTEM_ADAPTER = {
+    lstat: fs.lstat,
+    stat: fs.stat,
+    lstatSync: fs.lstatSync,
+    statSync: fs.statSync,
+    readdir: fs.readdir,
+    readdirSync: fs.readdirSync
+};
+function createFileSystemAdapter(fsMethods) {
+    if (fsMethods === undefined) {
+        return exports.FILE_SYSTEM_ADAPTER;
+    }
+    return Object.assign(Object.assign({}, exports.FILE_SYSTEM_ADAPTER), fsMethods);
+}
+exports.createFileSystemAdapter = createFileSystemAdapter;