fe_comment: recipients are the FE users of the feedback group

- The selectable recipients are no longer a hand-maintained setting but
  every active frontend user of the feedback group (feUserGroup) with a
  valid e-mail address; the id is the fe_users uid, so a stored selection
  survives users joining or leaving. The `recipients` setting is marked
  unused
- Each recipient in the state payload carries label, email and selected
  (the stored choice), for a checkbox list with "select all" above the
  submit button
- submit accepts the checked ids directly ({"recipients": [uids]}),
  validates them against the group, stores and uses them, and reports
  the addresses used as sentTo; no selection falls back to mailTo
- migrations/check_fecomment_user.php: all summaries and items of one
  user incl. deleted ones, for diagnosis

packages/fe_comment/Classes/Middleware/FeedbackApiMiddleware.php

@@ -79,7 +79,7 @@ final class FeedbackApiMiddleware implements MiddlewareInterface
                 $route === 'upload' => $this->upload($request, $user),
                 (bool)preg_match('#^attachment/(\d+)/delete$#', $route, $m) => $this->deleteAttachment($user, (int)$m[1]),
                 $route === 'summary' => $this->updateSummary($request, $user),
-                $route === 'submit' => $this->submit($user),
+                $route === 'submit' => $this->submit($request, $user),
                 default => new JsonResponse(['error' => 'unknown route'], 404),
             };
         } catch (\Throwable $e) {
@@ -237,7 +237,7 @@ final class FeedbackApiMiddleware implements MiddlewareInterface
     }
 
     /** @param array{uid:int,username:string,name:string,email:string} $user */
-    private function submit(array $user): ResponseInterface
+    private function submit(ServerRequestInterface $request, array $user): ResponseInterface
     {
         $summary = $this->openSummary($user['uid'], false);
         if ($summary === null) {
@@ -249,6 +249,19 @@ final class FeedbackApiMiddleware implements MiddlewareInterface
         }
 
         $recipientMap = $this->recipientMap();
+
+        // The checkbox selection may travel with the submit itself
+        // ({"recipients": [ids]}) - validated against the configured list,
+        // stored on the summary, then used. Without it the stored selection
+        // applies; an empty selection falls back to mailTo.
+        $body = $this->jsonBody($request);
+        if (array_key_exists('recipients', $body) && is_array($body['recipients'])) {
+            $chosenIds = array_values(array_intersect(array_map('intval', $body['recipients']), array_keys($recipientMap)));
+            $summary['recipients'] = implode(',', $chosenIds);
+            GeneralUtility::makeInstance(ConnectionPool::class)->getConnectionForTable(self::T_SUMMARY)
+                ->update(self::T_SUMMARY, ['recipients' => $summary['recipients'], 'tstamp' => time()], ['uid' => (int)$summary['uid']]);
+        }
+
         $chosen = GeneralUtility::intExplode(',', (string)$summary['recipients'], true);
         $to = [];
         foreach ($chosen as $id) {
@@ -307,7 +320,8 @@ final class FeedbackApiMiddleware implements MiddlewareInterface
 
         GeneralUtility::makeInstance(ConnectionPool::class)->getConnectionForTable(self::T_SUMMARY)
             ->update(self::T_SUMMARY, ['status' => 'sent', 'sent_at' => time(), 'tstamp' => time()], ['uid' => (int)$summary['uid']]);
-        return new JsonResponse(['ok' => true, 'sent' => count($payload['items'])]);
+        // sentTo: the addresses actually used, for the confirmation message
+        return new JsonResponse(['ok' => true, 'sent' => count($payload['items']), 'sentTo' => array_values($to)]);
     }
 
     // ---- helpers ------------------------------------------------------------
@@ -379,10 +393,10 @@ final class FeedbackApiMiddleware implements MiddlewareInterface
             ->update(self::T_FEEDBACK, ['attachments' => $count, 'tstamp' => time()], ['uid' => $feedbackUid]);
     }
 
-    /** @return array<int,array{label:string,email:string}> id => recipient */
+    /** @return array<int,array{label:string,email:string}> fe_users uid => recipient (FE users of the feedback group) */
     private function recipientMap(): array
     {
-        return $this->settings->recipients();
+        return $this->stateService()->recipientMap();
     }
 
     /** @return array<string,mixed> */