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/webpack-cli/lib/plugins/cli-plugin.d.ts

@@ -0,0 +1,12 @@
+import { type Compiler } from "webpack";
+import { type CLIPluginOptions } from "../types";
+export declare class CLIPlugin {
+    #private;
+    logger: ReturnType<Compiler["getInfrastructureLogger"]>;
+    options: CLIPluginOptions;
+    constructor(options: CLIPluginOptions);
+    setupBundleAnalyzerPlugin(compiler: Compiler): Promise<void>;
+    setupProgressPlugin(compiler: Compiler): void;
+    setupHelpfulOutput(compiler: Compiler): void;
+    apply(compiler: Compiler): void;
+}