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/@sentry/utils/esm/promisebuffer.d.ts

@@ -0,0 +1,11 @@
+export interface PromiseBuffer<T> {
+    $: Array<PromiseLike<T>>;
+    add(taskProducer: () => PromiseLike<T>): PromiseLike<T>;
+    drain(timeout?: number): PromiseLike<boolean>;
+}
+/**
+ * Creates an new PromiseBuffer object with the specified limit
+ * @param limit max number of promises that can be stored in the buffer
+ */
+export declare function makePromiseBuffer<T>(limit?: number): PromiseBuffer<T>;
+//# sourceMappingURL=promisebuffer.d.ts.map