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/table/dist/src/drawRow.d.ts

@@ -0,0 +1,10 @@
+import type { SpanningCellManager } from './spanningCellManager';
+import type { DrawVerticalLine } from './types/api';
+import type { BodyBorderConfig, Row } from './types/internal';
+export declare type DrawRowConfig = {
+    border: BodyBorderConfig;
+    drawVerticalLine: DrawVerticalLine;
+    spanningCellManager?: SpanningCellManager;
+    rowIndex?: number;
+};
+export declare const drawRow: (row: Row, config: DrawRowConfig) => string;