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/spanningCellManager.d.ts

@@ -0,0 +1,23 @@
+import type { DrawHorizontalLine, DrawVerticalLine, SpanningCellConfig } from './types/api';
+import type { CellCoordinates, ColumnConfig, ResolvedRangeConfig, Row } from './types/internal';
+export declare type SpanningCellManager = {
+    getContainingRange: (cell: CellCoordinates, options?: {
+        mapped: true;
+    }) => ResolvedRangeConfig | undefined;
+    inSameRange: (cell1: CellCoordinates, cell2: CellCoordinates) => boolean;
+    rowHeights: number[];
+    setRowHeights: (rowHeights: number[]) => void;
+    rowIndexMapping: number[];
+    setRowIndexMapping: (mappedRowHeights: number[]) => void;
+};
+export declare type SpanningCellParameters = {
+    spanningCellConfigs: SpanningCellConfig[];
+    rows: Row[];
+    columnsConfig: ColumnConfig[];
+    drawVerticalLine: DrawVerticalLine;
+    drawHorizontalLine: DrawHorizontalLine;
+};
+export declare type SpanningCellContext = SpanningCellParameters & {
+    rowHeights: number[];
+};
+export declare const createSpanningCellManager: (parameters: SpanningCellParameters) => SpanningCellManager;