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/@emotion/utils/dist/declarations/src/index.d.ts

@@ -0,0 +1,5 @@
+import { RegisteredCache, EmotionCache, SerializedStyles } from "./types.js";
+export declare function getRegisteredStyles(registered: RegisteredCache, registeredStyles: string[], classNames: string): string;
+export declare const registerStyles: (cache: EmotionCache, serialized: SerializedStyles, isStringTag: boolean) => void;
+export declare const insertStyles: (cache: EmotionCache, serialized: SerializedStyles, isStringTag: boolean) => string | undefined;
+export * from "./types.js";

node_modules/@emotion/utils/dist/declarations/src/types.d.ts

@@ -0,0 +1,17 @@
+import type { StyleSheet } from '@emotion/sheet';
+export type { StyleSheet };
+export type RegisteredCache = Record<string, string | undefined>;
+export type SerializedStyles = {
+    name: string;
+    styles: string;
+    next?: SerializedStyles;
+};
+export type EmotionCache = {
+    inserted: Record<string, string | true | undefined>;
+    registered: RegisteredCache;
+    sheet: StyleSheet;
+    key: string;
+    compat?: true;
+    nonce?: string;
+    insert: (selector: string, serialized: SerializedStyles, sheet: StyleSheet, shouldCache: boolean) => string | void;
+};