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/tsconfig-loader.d.ts

@@ -0,0 +1,28 @@
+/**
+ * Typing for the parts of tsconfig that we care about
+ */
+export interface Tsconfig {
+    extends?: string | string[];
+    compilerOptions?: {
+        baseUrl?: string;
+        paths?: {
+            [key: string]: Array<string>;
+        };
+        strict?: boolean;
+    };
+}
+export interface TsConfigLoaderResult {
+    tsConfigPath: string | undefined;
+    baseUrl: string | undefined;
+    paths: {
+        [key: string]: Array<string>;
+    } | undefined;
+}
+export interface TsConfigLoaderParams {
+    getEnv: (key: string) => string | undefined;
+    cwd: string;
+    loadSync?(cwd: string, filename?: string, baseUrl?: string): TsConfigLoaderResult;
+}
+export declare function tsConfigLoader({ getEnv, cwd, loadSync, }: TsConfigLoaderParams): TsConfigLoaderResult;
+export declare function walkForTsConfig(directory: string, existsSync?: (path: string) => boolean): string | undefined;
+export declare function loadTsconfig(configFilePath: string, existsSync?: (path: string) => boolean, readFileSync?: (filename: string) => string): Tsconfig | undefined;