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/css-select/lib/helpers/selectors.d.ts

@@ -0,0 +1,20 @@
+import type { InternalSelector } from "../types.js";
+import { type Traversal } from "css-what";
+export declare function isTraversal(token: InternalSelector): token is Traversal;
+/**
+ * Sort the parts of the passed selector, as there is potential for
+ * optimization (some types of selectors are faster than others).
+ *
+ * @param arr Selector to sort
+ */
+export declare function sortRules(arr: InternalSelector[]): void;
+/**
+ * Determine the quality of the passed token. The higher the number, the
+ * faster the token is to execute.
+ *
+ * @param token Token to get the quality of.
+ * @returns The token's quality.
+ */
+export declare function getQuality(token: InternalSelector): number;
+export declare function includesScopePseudo(t: InternalSelector): boolean;
+//# sourceMappingURL=selectors.d.ts.map