Fix Kalender-Suche: calendar_event_cache Tabelle, Sync-Endpoint, Dashboard-Trigger

frontend/src/App.jsx

@@ -1873,6 +1873,10 @@ function Dashboard({ toast, mobile, setActive, setDevToolsNav, unreadMsgs=0, unr
   const [showBoard,     setShowBoard]     = useState(false);
   const [showChangelog, setShowChangelog] = useState(false);
   useEffect(() => { const t = setInterval(() => setNow(new Date()), 30000); return () => clearInterval(t); }, []);
+  // Kalender-Events im Hintergrund für die Suche cachen
+  useEffect(() => {
+    api('/search/sync-calendar', { method:'POST', body:{} }).catch(()=>{});
+  }, []);
   return (
     <div style={{ padding: mobile ? '14px 12px 90px' : '36px 44px', maxWidth:1100 }}>
       {showBoard && <BoardModal user={user} toast={toast} onClose={()=>setShowBoard(false)} onRead={onBoardRead}/>}