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/framer-motion/dist/es/render/dom/motion-proxy.mjs

@@ -0,0 +1,47 @@
+import { createMotionComponent } from '../../motion/index.mjs';
+
+/**
+ * Convert any React component into a `motion` component. The provided component
+ * **must** use `React.forwardRef` to the underlying DOM component you want to animate.
+ *
+ * ```jsx
+ * const Component = React.forwardRef((props, ref) => {
+ *   return <div ref={ref} />
+ * })
+ *
+ * const MotionComponent = motion(Component)
+ * ```
+ *
+ * @public
+ */
+function createMotionProxy(createConfig) {
+    function custom(Component, customMotionComponentConfig = {}) {
+        return createMotionComponent(createConfig(Component, customMotionComponentConfig));
+    }
+    if (typeof Proxy === "undefined") {
+        return custom;
+    }
+    /**
+     * A cache of generated `motion` components, e.g `motion.div`, `motion.input` etc.
+     * Rather than generating them anew every render.
+     */
+    const componentCache = new Map();
+    return new Proxy(custom, {
+        /**
+         * Called when `motion` is referenced with a prop: `motion.div`, `motion.input` etc.
+         * The prop name is passed through as `key` and we can use that to generate a `motion`
+         * DOM component with that name.
+         */
+        get: (_target, key) => {
+            /**
+             * If this element doesn't exist in the component cache, create it and cache.
+             */
+            if (!componentCache.has(key)) {
+                componentCache.set(key, custom(key));
+            }
+            return componentCache.get(key);
+        },
+    });
+}
+
+export { createMotionProxy };