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/bare-events/global.d.ts

@@ -0,0 +1,15 @@
+import * as events from './web'
+
+type EventConstructor = typeof events.Event
+type CustomEventConstructor = typeof events.CustomEvent
+type EventTargetConstructor = typeof events.EventTarget
+
+declare global {
+  type Event = events.Event
+  type CustomEvent<T = any> = events.CustomEvent<T>
+  type EventTarget = events.EventTarget
+
+  const Event: EventConstructor
+  const CustomEvent: CustomEventConstructor
+  const EventTarget: EventTargetConstructor
+}