fe_comment: Feedback Overview content element in the page JSON

- New content element "Feedback Overview" (CType fecomment_overview):
  the current FE user's feedback state under content.feedbackOverview,
  so the overview page renders like any other page instead of a
  front-end special case
- Rendered as USER_INT inside the cached page JSON (EXT:headless replaces
  the field per request): data is per user, visitors without a session
  get {"allowed": false} - verified that nothing leaks from the cache
- One implementation for both consumers: the new FeedbackState service
  builds the state payload; the API middleware delegates to it
- State payload (API and element) gained canSubmit and actions (all
  write endpoints with method and URL), so the front end needs no
  hard-coded endpoints for the submit button below the ticket list
- New site set evomedien/fe-comment carries the TypoScript, added to the
  site configuration; icon fecomment-overview

packages/fe_comment/Classes/UserFunc/OverviewJsonRenderer.php

@@ -0,0 +1,36 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Evomedien\FeComment\UserFunc;
+
+use Evomedien\FeComment\Service\FeedbackState;
+use TYPO3\CMS\Core\Attribute\AsAllowedCallable;
+use TYPO3\CMS\Core\Utility\GeneralUtility;
+
+/**
+ * "Feedback Overview" content element (CType fecomment_overview,
+ * 2026-10-09): the current FE user's feedback state in the page JSON, under
+ * content.feedbackOverview - exactly the payload of GET
+ * /api/fe-comment/state (shared FeedbackState service), so a front end can
+ * render the overview page like any other page.
+ *
+ * Wired as USER_INT: the data is per user. EXT:headless keeps the page
+ * cached and replaces only this field per request. Visitors who are not
+ * allowed get {"allowed": false} (front end: redirect to the login page).
+ */
+final class OverviewJsonRenderer
+{
+    #[AsAllowedCallable]
+    public function render(string $content, array $conf): string
+    {
+        try {
+            $request = $GLOBALS['TYPO3_REQUEST'] ?? null;
+            $state = GeneralUtility::makeInstance(FeedbackState::class);
+            $payload = $request !== null ? $state->payload($state->allowedUser($request)) : ['allowed' => false];
+        } catch (\Throwable) {
+            $payload = ['allowed' => false];
+        }
+        return (string)json_encode($payload, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE);
+    }
+}