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/index.d.ts

@@ -0,0 +1,26 @@
+export * from "./Box";
+export * from "./Button";
+export * from "./Checkbox";
+export * from "./Clickable";
+export * from "./Combobox";
+export * from "./Composite";
+export * from "./Dialog";
+export * from "./Disclosure";
+export * from "./Form";
+export * from "./Grid";
+export * from "./Group";
+export * from "./Id";
+export * from "./Input";
+export * from "./Menu";
+export * from "./Popover";
+export * from "./Portal";
+export * from "./Radio";
+export * from "./Role";
+export * from "./Rover";
+export * from "./Separator";
+export * from "./Tab";
+export * from "./Tabbable";
+export * from "./Toolbar";
+export * from "./Tooltip";
+export * from "./VisuallyHidden";
+export * from "./Provider";