feat: add entry removal and row saving functionality, enhance admin components with localization

frontend/src/components/Admin.tsx

@@ -22,7 +22,7 @@ const Admin: React.FC = () => {
       {token ? (
         <Table />
       ) : (
-        <div className="p-4">Please log in as an admin.</div>
+        <div className="p-4">Bitte als Admin einloggen. Oder gehe <a className="text-blue-500 hover:underline" href="/">zurück</a>.</div>
       )}
     </>
   );