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/drop-zone/index.js

@@ -0,0 +1,186 @@
+"use strict";
+
+var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault");
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.DropZoneComponent = DropZoneComponent;
+exports.default = void 0;
+var _react = require("react");
+var _classnames = _interopRequireDefault(require("classnames"));
+var _i18n = require("@wordpress/i18n");
+var _element = require("@wordpress/element");
+var _icons = require("@wordpress/icons");
+var _dom = require("@wordpress/dom");
+var _compose = require("@wordpress/compose");
+var _animation = require("../animation");
+/**
+ * External dependencies
+ */
+
+/**
+ * WordPress dependencies
+ */
+
+/**
+ * Internal dependencies
+ */
+
+/**
+ * `DropZone` is a component creating a drop zone area taking the full size of its parent element. It supports dropping files, HTML content or any other HTML drop event.
+ *
+ * ```jsx
+ * import { DropZone } from '@wordpress/components';
+ * import { useState } from '@wordpress/element';
+ *
+ * const MyDropZone = () => {
+ *   const [ hasDropped, setHasDropped ] = useState( false );
+ *
+ *   return (
+ *     <div>
+ *       { hasDropped ? 'Dropped!' : 'Drop something here' }
+ *       <DropZone
+ *         onFilesDrop={ () => setHasDropped( true ) }
+ *         onHTMLDrop={ () => setHasDropped( true ) }
+ *         onDrop={ () => setHasDropped( true ) }
+ *       />
+ *     </div>
+ *   );
+ * }
+ * ```
+ */
+function DropZoneComponent({
+  className,
+  label,
+  onFilesDrop,
+  onHTMLDrop,
+  onDrop,
+  ...restProps
+}) {
+  const [isDraggingOverDocument, setIsDraggingOverDocument] = (0, _element.useState)();
+  const [isDraggingOverElement, setIsDraggingOverElement] = (0, _element.useState)();
+  const [type, setType] = (0, _element.useState)();
+  const ref = (0, _compose.__experimentalUseDropZone)({
+    onDrop(event) {
+      const files = event.dataTransfer ? (0, _dom.getFilesFromDataTransfer)(event.dataTransfer) : [];
+      const html = event.dataTransfer?.getData('text/html');
+
+      /**
+       * From Windows Chrome 96, the `event.dataTransfer` returns both file object and HTML.
+       * The order of the checks is important to recognise the HTML drop.
+       */
+      if (html && onHTMLDrop) {
+        onHTMLDrop(html);
+      } else if (files.length && onFilesDrop) {
+        onFilesDrop(files);
+      } else if (onDrop) {
+        onDrop(event);
+      }
+    },
+    onDragStart(event) {
+      setIsDraggingOverDocument(true);
+      let _type = 'default';
+
+      /**
+       * From Windows Chrome 96, the `event.dataTransfer` returns both file object and HTML.
+       * The order of the checks is important to recognise the HTML drop.
+       */
+      if (event.dataTransfer?.types.includes('text/html')) {
+        _type = 'html';
+      } else if (
+      // Check for the types because sometimes the files themselves
+      // are only available on drop.
+      event.dataTransfer?.types.includes('Files') || (event.dataTransfer ? (0, _dom.getFilesFromDataTransfer)(event.dataTransfer) : []).length > 0) {
+        _type = 'file';
+      }
+      setType(_type);
+    },
+    onDragEnd() {
+      setIsDraggingOverDocument(false);
+      setType(undefined);
+    },
+    onDragEnter() {
+      setIsDraggingOverElement(true);
+    },
+    onDragLeave() {
+      setIsDraggingOverElement(false);
+    }
+  });
+  const disableMotion = (0, _compose.useReducedMotion)();
+  let children;
+  const backdrop = {
+    hidden: {
+      opacity: 0
+    },
+    show: {
+      opacity: 1,
+      transition: {
+        type: 'tween',
+        duration: 0.2,
+        delay: 0,
+        delayChildren: 0.1
+      }
+    },
+    exit: {
+      opacity: 0,
+      transition: {
+        duration: 0.2,
+        delayChildren: 0
+      }
+    }
+  };
+  const foreground = {
+    hidden: {
+      opacity: 0,
+      scale: 0.9
+    },
+    show: {
+      opacity: 1,
+      scale: 1,
+      transition: {
+        duration: 0.1
+      }
+    },
+    exit: {
+      opacity: 0,
+      scale: 0.9
+    }
+  };
+  if (isDraggingOverElement) {
+    children = (0, _react.createElement)(_animation.__unstableMotion.div, {
+      variants: backdrop,
+      initial: disableMotion ? 'show' : 'hidden',
+      animate: "show",
+      exit: disableMotion ? 'show' : 'exit',
+      className: "components-drop-zone__content"
+      // Without this, when this div is shown,
+      // Safari calls a onDropZoneLeave causing a loop because of this bug
+      // https://bugs.webkit.org/show_bug.cgi?id=66547
+      ,
+      style: {
+        pointerEvents: 'none'
+      }
+    }, (0, _react.createElement)(_animation.__unstableMotion.div, {
+      variants: foreground
+    }, (0, _react.createElement)(_icons.Icon, {
+      icon: _icons.upload,
+      className: "components-drop-zone__content-icon"
+    }), (0, _react.createElement)("span", {
+      className: "components-drop-zone__content-text"
+    }, label ? label : (0, _i18n.__)('Drop files to upload'))));
+  }
+  const classes = (0, _classnames.default)('components-drop-zone', className, {
+    'is-active': (isDraggingOverDocument || isDraggingOverElement) && (type === 'file' && onFilesDrop || type === 'html' && onHTMLDrop || type === 'default' && onDrop),
+    'is-dragging-over-document': isDraggingOverDocument,
+    'is-dragging-over-element': isDraggingOverElement,
+    [`is-dragging-${type}`]: !!type
+  });
+  return (0, _react.createElement)("div", {
+    ...restProps,
+    ref: ref,
+    className: classes
+  }, disableMotion ? children : (0, _react.createElement)(_animation.__unstableAnimatePresence, null, children));
+}
+var _default = DropZoneComponent;
+exports.default = _default;
+//# sourceMappingURL=index.js.map

node_modules/@wordpress/components/build/drop-zone/provider.js

@@ -0,0 +1,22 @@
+"use strict";
+
+var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault");
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.default = DropZoneProvider;
+var _deprecated = _interopRequireDefault(require("@wordpress/deprecated"));
+/**
+ * WordPress dependencies
+ */
+
+function DropZoneProvider({
+  children
+}) {
+  (0, _deprecated.default)('wp.components.DropZoneProvider', {
+    since: '5.8',
+    hint: 'wp.component.DropZone no longer needs a provider. wp.components.DropZoneProvider is safe to remove from your code.'
+  });
+  return children;
+}
+//# sourceMappingURL=provider.js.map

node_modules/@wordpress/components/build/drop-zone/provider.js.map

@@ -0,0 +1 @@
+{"version":3,"names":["_deprecated","_interopRequireDefault","require","DropZoneProvider","children","deprecated","since","hint"],"sources":["@wordpress/components/src/drop-zone/provider.ts"],"sourcesContent":["/**\n * WordPress dependencies\n */\nimport deprecated from '@wordpress/deprecated';\n\nexport default function DropZoneProvider( {\n\tchildren,\n}: {\n\tchildren: React.ReactNode;\n} ) {\n\tdeprecated( 'wp.components.DropZoneProvider', {\n\t\tsince: '5.8',\n\t\thint: 'wp.component.DropZone no longer needs a provider. wp.components.DropZoneProvider is safe to remove from your code.',\n\t} );\n\treturn children;\n}\n"],"mappings":";;;;;;;AAGA,IAAAA,WAAA,GAAAC,sBAAA,CAAAC,OAAA;AAHA;AACA;AACA;;AAGe,SAASC,gBAAgBA,CAAE;EACzCC;AAGD,CAAC,EAAG;EACH,IAAAC,mBAAU,EAAE,gCAAgC,EAAE;IAC7CC,KAAK,EAAE,KAAK;IACZC,IAAI,EAAE;EACP,CAAE,CAAC;EACH,OAAOH,QAAQ;AAChB"}

node_modules/@wordpress/components/build/drop-zone/types.js

@@ -0,0 +1,6 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+//# sourceMappingURL=types.js.map

node_modules/@wordpress/components/build/drop-zone/types.js.map

@@ -0,0 +1 @@
+{"version":3,"names":[],"sources":["@wordpress/components/src/drop-zone/types.ts"],"sourcesContent":["export type DropType = 'file' | 'html' | 'default';\n\nexport type DropZoneProps = {\n\t/**\n\t * A CSS `class` to give to the wrapper element.\n\t */\n\tclassName?: string;\n\t/**\n\t * A string to be shown within the drop zone area.\n\t *\n\t * @default `__( 'Drop files to upload' )`\n\t */\n\tlabel?: string;\n\t/**\n\t * The function is generic drop handler called if the `onFilesDrop` or `onHTMLDrop` are not called.\n\t * It receives the drop `event` object as an argument.\n\t */\n\tonDrop?: ( event: DragEvent ) => void;\n\t/**\n\t * The function is called when dropping a file into the `DropZone`.\n\t * It receives an array of dropped files as an argument.\n\t */\n\tonFilesDrop?: ( files: File[] ) => void;\n\t/**\n\t * The function is called when dropping HTML into the `DropZone`.\n\t * It receives the HTML being dropped as an argument.\n\t */\n\tonHTMLDrop?: ( html: string ) => void;\n};\n"],"mappings":""}