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/@wordpress/components/build-module/snackbar/index.js

@@ -0,0 +1,141 @@
+import { createElement } from "react";
+/**
+ * External dependencies
+ */
+
+import classnames from 'classnames';
+
+/**
+ * WordPress dependencies
+ */
+import { speak } from '@wordpress/a11y';
+import { useEffect, forwardRef, renderToString } from '@wordpress/element';
+import { __ } from '@wordpress/i18n';
+import warning from '@wordpress/warning';
+
+/**
+ * Internal dependencies
+ */
+import Button from '../button';
+const NOTICE_TIMEOUT = 10000;
+
+/**
+ * Custom hook which announces the message with the given politeness, if a
+ * valid message is provided.
+ *
+ * @param message    Message to announce.
+ * @param politeness Politeness to announce.
+ */
+function useSpokenMessage(message, politeness) {
+  const spokenMessage = typeof message === 'string' ? message : renderToString(message);
+  useEffect(() => {
+    if (spokenMessage) {
+      speak(spokenMessage, politeness);
+    }
+  }, [spokenMessage, politeness]);
+}
+function UnforwardedSnackbar({
+  className,
+  children,
+  spokenMessage = children,
+  politeness = 'polite',
+  actions = [],
+  onRemove,
+  icon = null,
+  explicitDismiss = false,
+  // onDismiss is a callback executed when the snackbar is dismissed.
+  // It is distinct from onRemove, which _looks_ like a callback but is
+  // actually the function to call to remove the snackbar from the UI.
+  onDismiss,
+  listRef
+}, ref) {
+  function dismissMe(event) {
+    if (event && event.preventDefault) {
+      event.preventDefault();
+    }
+
+    // Prevent focus loss by moving it to the list element.
+    listRef?.current?.focus();
+    onDismiss?.();
+    onRemove?.();
+  }
+  function onActionClick(event, onClick) {
+    event.stopPropagation();
+    onRemove?.();
+    if (onClick) {
+      onClick(event);
+    }
+  }
+  useSpokenMessage(spokenMessage, politeness);
+
+  // Only set up the timeout dismiss if we're not explicitly dismissing.
+  useEffect(() => {
+    const timeoutHandle = setTimeout(() => {
+      if (!explicitDismiss) {
+        onDismiss?.();
+        onRemove?.();
+      }
+    }, NOTICE_TIMEOUT);
+    return () => clearTimeout(timeoutHandle);
+  }, [onDismiss, onRemove, explicitDismiss]);
+  const classes = classnames(className, 'components-snackbar', {
+    'components-snackbar-explicit-dismiss': !!explicitDismiss
+  });
+  if (actions && actions.length > 1) {
+    // We need to inform developers that snackbar only accepts 1 action.
+    typeof SCRIPT_DEBUG !== "undefined" && SCRIPT_DEBUG === true ? warning('Snackbar can only have 1 action, use Notice if your message require many messages') : void 0;
+    // return first element only while keeping it inside an array
+    actions = [actions[0]];
+  }
+  const snackbarContentClassnames = classnames('components-snackbar__content', {
+    'components-snackbar__content-with-icon': !!icon
+  });
+  return createElement("div", {
+    ref: ref,
+    className: classes,
+    onClick: !explicitDismiss ? dismissMe : undefined,
+    tabIndex: 0,
+    role: !explicitDismiss ? 'button' : '',
+    onKeyPress: !explicitDismiss ? dismissMe : undefined,
+    "aria-label": !explicitDismiss ? __('Dismiss this notice') : ''
+  }, createElement("div", {
+    className: snackbarContentClassnames
+  }, icon && createElement("div", {
+    className: "components-snackbar__icon"
+  }, icon), children, actions.map(({
+    label,
+    onClick,
+    url
+  }, index) => {
+    return createElement(Button, {
+      key: index,
+      href: url,
+      variant: "tertiary",
+      onClick: event => onActionClick(event, onClick),
+      className: "components-snackbar__action"
+    }, label);
+  }), explicitDismiss && createElement("span", {
+    role: "button",
+    "aria-label": "Dismiss this notice",
+    tabIndex: 0,
+    className: "components-snackbar__dismiss-button",
+    onClick: dismissMe,
+    onKeyPress: dismissMe
+  }, "\u2715")));
+}
+
+/**
+ * A Snackbar displays a succinct message that is cleared out after a small delay.
+ *
+ * It can also offer the user options, like viewing a published post.
+ * But these options should also be available elsewhere in the UI.
+ *
+ * ```jsx
+ * const MySnackbarNotice = () => (
+ *   <Snackbar>Post published successfully.</Snackbar>
+ * );
+ * ```
+ */
+export const Snackbar = forwardRef(UnforwardedSnackbar);
+export default Snackbar;
+//# sourceMappingURL=index.js.map

node_modules/@wordpress/components/build-module/snackbar/list.js

@@ -0,0 +1,99 @@
+import { createElement } from "react";
+/**
+ * External dependencies
+ */
+import classnames from 'classnames';
+
+/**
+ * WordPress dependencies
+ */
+import { useReducedMotion } from '@wordpress/compose';
+import { useRef } from '@wordpress/element';
+
+/**
+ * Internal dependencies
+ */
+import Snackbar from '.';
+import { __unstableMotion as motion, __unstableAnimatePresence as AnimatePresence } from '../animation';
+const SNACKBAR_VARIANTS = {
+  init: {
+    height: 0,
+    opacity: 0
+  },
+  open: {
+    height: 'auto',
+    opacity: 1,
+    transition: {
+      height: {
+        type: 'tween',
+        duration: 0.3,
+        ease: [0, 0, 0.2, 1]
+      },
+      opacity: {
+        type: 'tween',
+        duration: 0.25,
+        delay: 0.05,
+        ease: [0, 0, 0.2, 1]
+      }
+    }
+  },
+  exit: {
+    opacity: 0,
+    transition: {
+      type: 'tween',
+      duration: 0.1,
+      ease: [0, 0, 0.2, 1]
+    }
+  }
+};
+
+/**
+ * Renders a list of notices.
+ *
+ * ```jsx
+ * const MySnackbarListNotice = () => (
+ *   <SnackbarList
+ *     notices={ notices }
+ *     onRemove={ removeNotice }
+ *   />
+ * );
+ * ```
+ */
+export function SnackbarList({
+  notices,
+  className,
+  children,
+  onRemove
+}) {
+  const listRef = useRef(null);
+  const isReducedMotion = useReducedMotion();
+  className = classnames('components-snackbar-list', className);
+  const removeNotice = notice => () => onRemove?.(notice.id);
+  return createElement("div", {
+    className: className,
+    tabIndex: -1,
+    ref: listRef
+  }, children, createElement(AnimatePresence, null, notices.map(notice => {
+    const {
+      content,
+      ...restNotice
+    } = notice;
+    return createElement(motion.div, {
+      layout: !isReducedMotion // See https://www.framer.com/docs/animation/#layout-animations
+      ,
+      initial: 'init',
+      animate: 'open',
+      exit: 'exit',
+      key: notice.id,
+      variants: isReducedMotion ? undefined : SNACKBAR_VARIANTS
+    }, createElement("div", {
+      className: "components-snackbar-list__notice-container"
+    }, createElement(Snackbar, {
+      ...restNotice,
+      onRemove: removeNotice(notice),
+      listRef: listRef
+    }, notice.content)));
+  })));
+}
+export default SnackbarList;
+//# sourceMappingURL=list.js.map

node_modules/@wordpress/components/build-module/snackbar/types.js

@@ -0,0 +1,2 @@
+export {};
+//# sourceMappingURL=types.js.map

node_modules/@wordpress/components/build-module/snackbar/types.js.map

@@ -0,0 +1 @@
+{"version":3,"names":[],"sources":["@wordpress/components/src/snackbar/types.ts"],"sourcesContent":["/**\n * External dependencies\n */\nimport type { MutableRefObject, ReactNode } from 'react';\n\n/**\n * Internal dependencies\n */\nimport type { NoticeProps, NoticeChildren } from '../notice/types';\n\ntype SnackbarOnlyProps = {\n\t/**\n\t * The icon to render in the snackbar.\n\t *\n\t * @default null\n\t */\n\ticon?: ReactNode;\n\t/**\n\t * Whether to require user action to dismiss the snackbar.\n\t * By default, this is dismissed on a timeout, without user interaction.\n\t *\n\t * @default false\n\t */\n\texplicitDismiss?: boolean;\n\t/**\n\t * A ref to the list that contains the snackbar.\n\t */\n\tlistRef?: MutableRefObject< HTMLDivElement | null >;\n};\n\nexport type SnackbarProps = Omit< NoticeProps, '__unstableHTML' > &\n\tSnackbarOnlyProps;\n\nexport type SnackbarListProps = {\n\tnotices: Array<\n\t\tOmit< SnackbarProps, 'children' > & {\n\t\t\tid: string;\n\t\t\tcontent: string;\n\t\t}\n\t>;\n\tonRemove: ( id: string ) => void;\n\tchildren?: NoticeChildren | Array< NoticeChildren >;\n};\n"],"mappings":""}