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/motion/utils/unwrap-motion-component.mjs

@@ -0,0 +1,17 @@
+import { isMotionComponent } from './is-motion-component.mjs';
+import { motionComponentSymbol } from './symbol.mjs';
+
+/**
+ * Unwraps a `motion` component and returns either a string for `motion.div` or
+ * the React component for `motion(Component)`.
+ *
+ * If the component is not a `motion` component it returns undefined.
+ */
+function unwrapMotionComponent(component) {
+    if (isMotionComponent(component)) {
+        return component[motionComponentSymbol];
+    }
+    return undefined;
+}
+
+export { unwrapMotionComponent };