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/rxjs/dist/esm/internal/observable/partition.js

@@ -0,0 +1,7 @@
+import { not } from '../util/not';
+import { filter } from '../operators/filter';
+import { innerFrom } from './innerFrom';
+export function partition(source, predicate, thisArg) {
+    return [filter(predicate, thisArg)(innerFrom(source)), filter(not(predicate, thisArg))(innerFrom(source))];
+}
+//# sourceMappingURL=partition.js.map