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/reakit/ts/Id/Id.d.ts

@@ -0,0 +1,32 @@
+import * as React from "react";
+import { RoleHTMLProps } from "../Role/Role";
+import { unstable_IdStateReturn } from "./IdState";
+export declare type unstable_IdOptions = Pick<Partial<unstable_IdStateReturn>, "baseId" | "unstable_idCountRef"> & {
+    /**
+     * Same as the HTML attribute.
+     */
+    id?: string;
+};
+export declare type unstable_IdHTMLProps = RoleHTMLProps;
+export declare type unstable_IdProps = unstable_IdOptions & unstable_IdHTMLProps;
+export declare const unstable_useId: {
+    (options?: unstable_IdOptions | undefined, htmlProps?: RoleHTMLProps | undefined, unstable_ignoreUseOptions?: boolean | undefined): RoleHTMLProps;
+    unstable_propsAreEqual: (prev: Pick<Partial<unstable_IdStateReturn>, "baseId" | "unstable_idCountRef"> & {
+        /**
+         * Same as the HTML attribute.
+         */
+        id?: string | undefined;
+    } & React.HTMLAttributes<any> & React.RefAttributes<any> & {
+        wrapElement?: ((element: React.ReactNode) => React.ReactNode) | undefined;
+    }, next: Pick<Partial<unstable_IdStateReturn>, "baseId" | "unstable_idCountRef"> & {
+        /**
+         * Same as the HTML attribute.
+         */
+        id?: string | undefined;
+    } & React.HTMLAttributes<any> & React.RefAttributes<any> & {
+        wrapElement?: ((element: React.ReactNode) => React.ReactNode) | undefined;
+    }) => boolean;
+    __keys: readonly any[];
+    __useOptions: (options: unstable_IdOptions, htmlProps: RoleHTMLProps) => unstable_IdOptions;
+};
+export declare const unstable_Id: import("reakit-system/ts/createComponent").Component<"div", unstable_IdOptions>;