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/memfs/lib/internal/errors.d.ts

@@ -0,0 +1,32 @@
+/// <reference types="node" />
+declare const g: typeof globalThis | NodeJS.Global;
+declare class AssertionError extends g.Error {
+    generatedMessage: any;
+    name: any;
+    code: any;
+    actual: any;
+    expected: any;
+    operator: any;
+    constructor(options: any);
+}
+declare function message(key: any, args: any): any;
+declare function E(sym: any, val: any): void;
+export declare const Error: {
+    new (key: any, ...args: any[]): {
+        [x: string]: any;
+    };
+    [x: string]: any;
+};
+export declare const TypeError: {
+    new (key: any, ...args: any[]): {
+        [x: string]: any;
+    };
+    [x: string]: any;
+};
+export declare const RangeError: {
+    new (key: any, ...args: any[]): {
+        [x: string]: any;
+    };
+    [x: string]: any;
+};
+export { message, AssertionError, E, };