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/web-vitals/dist/modules/attribution.d.ts

@@ -0,0 +1,13 @@
+export { onCLS } from './attribution/onCLS.js';
+export { onFCP } from './attribution/onFCP.js';
+export { onFID } from './attribution/onFID.js';
+export { onINP } from './attribution/onINP.js';
+export { onLCP } from './attribution/onLCP.js';
+export { onTTFB } from './attribution/onTTFB.js';
+export { CLSThresholds } from './onCLS.js';
+export { FCPThresholds } from './onFCP.js';
+export { FIDThresholds } from './onFID.js';
+export { INPThresholds } from './onINP.js';
+export { LCPThresholds } from './onLCP.js';
+export { TTFBThresholds } from './onTTFB.js';
+export * from './types.js';