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/Menu/Menu.d.ts

@@ -0,0 +1,28 @@
+import * as React from "react";
+import { PopoverOptions, PopoverHTMLProps } from "../Popover/Popover";
+import { MenuBarOptions, MenuBarHTMLProps } from "./MenuBar";
+import { MenuStateReturn } from "./MenuState";
+export declare type MenuOptions = Omit<PopoverOptions, "hideOnEsc"> & Pick<MenuStateReturn, "placement"> & MenuBarOptions;
+export declare type MenuHTMLProps = PopoverHTMLProps & MenuBarHTMLProps;
+export declare type MenuProps = MenuOptions & MenuHTMLProps;
+export declare const useMenu: {
+    (options?: MenuOptions | undefined, htmlProps?: import("..").TabbableHTMLProps | undefined, unstable_ignoreUseOptions?: boolean | undefined): import("..").TabbableHTMLProps;
+    unstable_propsAreEqual: (prev: Pick<PopoverOptions, "hide" | "visible" | "unstable_system" | "baseId" | "animated" | "animating" | "modal" | "unstable_disclosureRef" | "unstable_popoverRef" | "unstable_popoverStyles" | "stopAnimation" | "hideOnClickOutside" | "preventBodyScroll" | "unstable_initialFocusRef" | "unstable_finalFocusRef" | "unstable_orphan" | "unstable_autoFocusOnShow" | "unstable_autoFocusOnHide"> & Pick<MenuStateReturn, "placement"> & import("..").RoleOptions & {
+        disabled?: boolean | undefined;
+        focusable?: boolean | undefined;
+    } & Pick<Partial<import("..").CompositeStateReturn>, "wrap" | "orientation" | "baseId" | "currentId" | "unstable_virtual" | "groups" | "unstable_moves"> & Pick<import("..").CompositeStateReturn, "move" | "first" | "last" | "items" | "setCurrentId"> & Pick<Partial<MenuStateReturn>, "orientation"> & Pick<MenuStateReturn, "next" | "move" | "items" | "previous"> & React.HTMLAttributes<any> & React.RefAttributes<any> & {
+        wrapElement?: ((element: React.ReactNode) => React.ReactNode) | undefined;
+    } & {
+        disabled?: boolean | undefined;
+    }, next: Pick<PopoverOptions, "hide" | "visible" | "unstable_system" | "baseId" | "animated" | "animating" | "modal" | "unstable_disclosureRef" | "unstable_popoverRef" | "unstable_popoverStyles" | "stopAnimation" | "hideOnClickOutside" | "preventBodyScroll" | "unstable_initialFocusRef" | "unstable_finalFocusRef" | "unstable_orphan" | "unstable_autoFocusOnShow" | "unstable_autoFocusOnHide"> & Pick<MenuStateReturn, "placement"> & import("..").RoleOptions & {
+        disabled?: boolean | undefined;
+        focusable?: boolean | undefined;
+    } & Pick<Partial<import("..").CompositeStateReturn>, "wrap" | "orientation" | "baseId" | "currentId" | "unstable_virtual" | "groups" | "unstable_moves"> & Pick<import("..").CompositeStateReturn, "move" | "first" | "last" | "items" | "setCurrentId"> & Pick<Partial<MenuStateReturn>, "orientation"> & Pick<MenuStateReturn, "next" | "move" | "items" | "previous"> & React.HTMLAttributes<any> & React.RefAttributes<any> & {
+        wrapElement?: ((element: React.ReactNode) => React.ReactNode) | undefined;
+    } & {
+        disabled?: boolean | undefined;
+    }) => boolean;
+    __keys: readonly any[];
+    __useOptions: (options: MenuOptions, htmlProps: import("..").TabbableHTMLProps) => MenuOptions;
+};
+export declare const Menu: import("reakit-system/ts/createComponent").Component<"div", MenuOptions>;