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/tsconfig-paths/lib/try-path.d.ts

@@ -0,0 +1,15 @@
+import { MappingEntry } from "./mapping-entry";
+export interface TryPath {
+    readonly type: "file" | "extension" | "index" | "package";
+    readonly path: string;
+}
+/**
+ * Builds a list of all physical paths to try by:
+ * 1. Check for file named exactly as request.
+ * 2. Check for files named as request ending in any of the extensions.
+ * 3. Check for file specified in package.json's main property.
+ * 4. Check for files named as request ending in "index" with any of the extensions.
+ */
+export declare function getPathsToTry(extensions: ReadonlyArray<string>, absolutePathMappings: ReadonlyArray<MappingEntry>, requestedModule: string): ReadonlyArray<TryPath> | undefined;
+export declare function getStrippedPath(tryPath: TryPath): string;
+export declare function exhaustiveTypeException(check: never): never;