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/ajv-formats/dist/index.d.ts

@@ -0,0 +1,15 @@
+import { FormatMode, FormatName } from "./formats";
+import type { Plugin, Format } from "ajv";
+export { FormatMode, FormatName } from "./formats";
+export { LimitFormatError } from "./limit";
+export interface FormatOptions {
+    mode?: FormatMode;
+    formats?: FormatName[];
+    keywords?: boolean;
+}
+export declare type FormatsPluginOptions = FormatName[] | FormatOptions;
+export interface FormatsPlugin extends Plugin<FormatsPluginOptions> {
+    get: (format: FormatName, mode?: FormatMode) => Format;
+}
+declare const formatsPlugin: FormatsPlugin;
+export default formatsPlugin;