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/src/Portal/Portal.tsx

@@ -0,0 +1,58 @@
+import * as React from "react";
+import * as ReactDOM from "react-dom";
+import { useIsomorphicEffect } from "reakit-utils/useIsomorphicEffect";
+import { canUseDOM } from "reakit-utils/canUseDOM";
+
+export type PortalProps = {
+  /**
+   * Portal's children.
+   */
+  children: React.ReactNode;
+};
+
+function getBodyElement() {
+  return canUseDOM ? document.body : null;
+}
+
+export const PortalContext = React.createContext<HTMLElement | null>(
+  getBodyElement()
+);
+
+export function Portal({ children }: PortalProps) {
+  // if it's a nested portal, context is the parent portal
+  // otherwise it's document.body
+  // https://github.com/reakit/reakit/issues/513
+  const context = React.useContext(PortalContext) || getBodyElement();
+  const [hostNode] = React.useState(() => {
+    if (canUseDOM) {
+      const element = document.createElement("div");
+      element.className = Portal.__className;
+      return element;
+    }
+    // ssr
+    return null;
+  });
+
+  useIsomorphicEffect(() => {
+    if (!hostNode || !context) return undefined;
+    context.appendChild(hostNode);
+    return () => {
+      context.removeChild(hostNode);
+    };
+  }, [hostNode, context]);
+
+  if (hostNode) {
+    return ReactDOM.createPortal(
+      <PortalContext.Provider value={hostNode}>
+        {children}
+      </PortalContext.Provider>,
+      hostNode
+    );
+  }
+
+  // ssr
+  return null;
+}
+
+Portal.__className = "__reakit-portal";
+Portal.__selector = `.${Portal.__className}`;

node_modules/reakit/src/Portal/README.md

@@ -0,0 +1,33 @@
+---
+path: /docs/portal/
+redirect_from:
+  - /components/portal/
+---
+
+# Portal
+
+`Portal` is an abstract wrapper component that uses [React Portals](https://reactjs.org/docs/portals.html) underneath. It can be used to put anything in a portal and supports nested portals.
+
+<carbon-ad></carbon-ad>
+
+## Installation
+
+```sh
+npm install reakit
+```
+
+Learn more in [Get started](/docs/get-started/).
+
+## Usage
+
+```jsx
+import { Portal } from "reakit/Portal";
+
+function Example() {
+  return (
+    <div style={{ background: "red", color: "white" }}>
+      I am here, <Portal>but I am detached at the bottom of the page.</Portal>
+    </div>
+  );
+}
+```

node_modules/reakit/src/Portal/__tests__/Portal-test.tsx

@@ -0,0 +1,73 @@
+import * as React from "react";
+import { render } from "reakit-test-utils";
+import { Portal } from "../Portal";
+
+test("render", () => {
+  const { baseElement } = render(<Portal>portal</Portal>);
+  expect(baseElement).toMatchInlineSnapshot(`
+    <body>
+      <div />
+      <div
+        class="__reakit-portal"
+      >
+        portal
+      </div>
+    </body>
+  `);
+});
+
+test("render nested", () => {
+  const { baseElement } = render(
+    <Portal>
+      portal1
+      <Portal>portal2</Portal>
+    </Portal>
+  );
+  expect(baseElement).toMatchInlineSnapshot(`
+    <body>
+      <div />
+      <div
+        class="__reakit-portal"
+      >
+        portal1
+        <div
+          class="__reakit-portal"
+        >
+          portal2
+        </div>
+      </div>
+    </body>
+  `);
+});
+
+test("render nested and sibling", () => {
+  const { baseElement } = render(
+    <>
+      <Portal>
+        portal1
+        <Portal>portal2</Portal>
+      </Portal>
+      <Portal>portal3</Portal>
+    </>
+  );
+  expect(baseElement).toMatchInlineSnapshot(`
+    <body>
+      <div />
+      <div
+        class="__reakit-portal"
+      >
+        portal1
+        <div
+          class="__reakit-portal"
+        >
+          portal2
+        </div>
+      </div>
+      <div
+        class="__reakit-portal"
+      >
+        portal3
+      </div>
+    </body>
+  `);
+});

node_modules/reakit/src/Portal/index.ts

@@ -0,0 +1 @@
+export * from "./Portal";