feat(feedback): Feedback-Formular mit Ntfy-Versand

Nutzer können Feedback aus dem Header senden; der Server leitet Nachrichten über Ntfy weiter (NTFY_* in .env).

Co-authored-by: Cursor <cursoragent@cursor.com>

client/src/components/LogbookDashboard.tsx

@@ -10,6 +10,7 @@ import { useDialog } from './ModalDialog.tsx'
 import AccountDangerZone from './AccountDangerZone.tsx'
 import { BookOpen, Plus, Trash2, LogOut, Languages, RefreshCw, Ship, User, Wifi, WifiOff } from 'lucide-react'
 import DisclaimerHeaderButton from './DisclaimerHeaderButton.tsx'
+import FeedbackHeaderButton from './FeedbackHeaderButton.tsx'
 
 interface LogbookDashboardProps {
   onSelectLogbook: (id: string, title: string) => void
@@ -217,6 +218,8 @@ export default function LogbookDashboard({ onSelectLogbook, onLogout }: LogbookD
 
           <DisclaimerHeaderButton />
 
+          <FeedbackHeaderButton />
+
           {/* Logout */}
           <button className="btn-icon logout" onClick={handleLogout} title={t('dashboard.logout')}>
             <LogOut size={18} />