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/testing/HotObservable.js

@@ -0,0 +1,37 @@
+import { Subject } from '../Subject';
+import { Subscription } from '../Subscription';
+import { SubscriptionLoggable } from './SubscriptionLoggable';
+import { applyMixins } from '../util/applyMixins';
+import { observeNotification } from '../Notification';
+export class HotObservable extends Subject {
+    constructor(messages, scheduler) {
+        super();
+        this.messages = messages;
+        this.subscriptions = [];
+        this.scheduler = scheduler;
+    }
+    _subscribe(subscriber) {
+        const subject = this;
+        const index = subject.logSubscribedFrame();
+        const subscription = new Subscription();
+        subscription.add(new Subscription(() => {
+            subject.logUnsubscribedFrame(index);
+        }));
+        subscription.add(super._subscribe(subscriber));
+        return subscription;
+    }
+    setup() {
+        const subject = this;
+        const messagesLength = subject.messages.length;
+        for (let i = 0; i < messagesLength; i++) {
+            (() => {
+                const { notification, frame } = subject.messages[i];
+                subject.scheduler.schedule(() => {
+                    observeNotification(notification, subject);
+                }, frame);
+            })();
+        }
+    }
+}
+applyMixins(HotObservable, [SubscriptionLoggable]);
+//# sourceMappingURL=HotObservable.js.map