FEATURE: Implement EditPreviewModes for Neos 9 with the new CR

Since nodes have no context in Neos 9 the edit preview mode cannot be decided by asking the node any more.

This change renovates the `UserInterfaceMode` and the `UserInterfaceModeService` to use php 8 value objects.
The UserInterfaceMode object is then added as globalValue `userInterfaceMode` to the `Neos\Neos\FusionView`.

The uses of the following fusion expressions have to be adjusted as follows:

- `node.context.live` - `!renderingMode.isEdit`
- `node.context.currentRenderingMode.edit` - `renderingMode.isEdit`
- `node.context.currentRenderingMode.preview` - `renderingMode.isPreview`
- `node.context.currentRenderingMode.name` - `renderingMode.name`

Resolves: #4086

Neos.Neos/Classes/Controller/Frontend/NodeController.php

@@ -36,6 +36,7 @@
 use Neos\Flow\Session\SessionInterface;
 use Neos\Flow\Utility\Now;
 use Neos\Neos\Domain\Service\NodeSiteResolvingService;
+use Neos\Neos\Domain\Service\RenderingModeService;
 use Neos\Neos\FrontendRouting\Exception\InvalidShortcutException;
 use Neos\Neos\FrontendRouting\Exception\NodeNotFoundException;
 use Neos\Neos\FrontendRouting\NodeAddress;
@@ -108,8 +109,12 @@ class NodeController extends ActionController
      */
     protected $nodeSiteResolvingService;
 
+    #[Flow\Inject]
+    protected RenderingModeService $renderingModeService;
+
     /**
      * @param string $node Legacy name for backwards compatibility of route components
+     * @param string $renderingModeName Name of the user interface mode to use
      * @throws NodeNotFoundException
      * @throws \Neos\Flow\Mvc\Exception\StopActionException
      * @throws \Neos\Flow\Mvc\Exception\UnsupportedRequestTypeException
@@ -120,8 +125,14 @@ class NodeController extends ActionController
      * with unsafe requests from widgets or plugins that are rendered on the node
      * - For those the CSRF token is validated on the sub-request, so it is safe to be skipped here
      */
-    public function previewAction(string $node): void
+    public function previewAction(string $node, string $renderingModeName = null): void
     {
+        if (is_null($renderingModeName)) {
+            $renderingMode = $this->renderingModeService->findByCurrentUser();
+        } else {
+            $renderingMode = $this->renderingModeService->findByName($renderingModeName);
+        }
+
         $visibilityConstraints = VisibilityConstraints::frontend();
         if ($this->privilegeManager->isPrivilegeTargetGranted('Neos.Neos:Backend.GeneralAccess')) {
             $visibilityConstraints = VisibilityConstraints::withoutRestrictions();
@@ -161,6 +172,8 @@ public function previewAction(string $node): void
             $this->handleShortcutNode($nodeAddress, $contentRepository);
         }
 
+        $this->view->setOption('renderingModeName', $renderingMode->name);
+
         $this->view->assignMultiple([
             'value' => $nodeInstance,
             'site' => $site,
@@ -234,6 +247,8 @@ public function showAction(string $node, bool $showInvisible = false): void
             $this->handleShortcutNode($nodeAddress, $contentRepository);
         }
 
+        $this->view->setOption('renderingModeName', 'frontend');
+
         $this->view->assignMultiple([
             'value' => $nodeInstance,
             'site' => $site,

Neos.Neos/Classes/Domain/Model/RenderingMode.php

@@ -0,0 +1,71 @@
+<?php
+
+/*
+ * This file is part of the Neos.Neos package.
+ *
+ * (c) Contributors of the Neos Project - www.neos.io
+ *
+ * This package is Open Source Software. For the full copyright and license
+ * information, please view the LICENSE file which was distributed with this
+ * source code.
+ */
+
+declare(strict_types=1);
+
+namespace Neos\Neos\Domain\Model;
+
+use Neos\Utility\ObjectAccess;
+
+/**
+ * Describes the mode in which the Neos interface is rendering currently,
+ * mainly distinguishing between edit and preview modes currently.
+ */
+class RenderingMode
+{
+    /**
+     * @param array<string,mixed> $options
+     */
+    public function __construct(
+        public readonly string $name,
+        public readonly bool $isEdit,
+        public readonly bool $isPreview,
+        public readonly string $title,
+        public readonly string $fusionPath,
+        public readonly array $options
+    ) {
+    }
+
+    /**
+     * Creates an UserInterfaceMode object by configuration
+     *
+     * @param string $modeName
+     * @param array<string,mixed> $configuration
+     */
+    public static function createFromConfiguration(string $modeName, array $configuration): RenderingMode
+    {
+        $mode = new RenderingMode(
+            $modeName,
+            $configuration['isEditingMode'] ?? false,
+            $configuration['isPreviewMode'] ?? false,
+            $configuration['title'] ?? $modeName,
+            $configuration['fusionRenderingPath'] ?? '',
+            $configuration['options'] ?? [],
+        );
+        return $mode;
+    }
+
+    /**
+     * Creates the live User interface mode
+     */
+    public static function createFrontend(): RenderingMode
+    {
+        return new RenderingMode(
+            'frontend',
+            false,
+            false,
+            'Frontend',
+            '',
+            []
+        );
+    }
+}