added security settings

changed fixes and issues

frontend/src/components/Settings.jsx

@@ -12,7 +12,7 @@ export function Settings({ nodes, onChanged }) {
   const [error, setError] = useState('');
 
   const requiredMissing = useMemo(
-    () => fields.filter((field) => field.required && !String(values[field.key] || '').trim()),
+    () => fields.filter((field) => field.required && !field.hasValue && !String(values[field.key] || '').trim()),
     [fields, values],
   );
 
@@ -100,6 +100,7 @@ export function Settings({ nodes, onChanged }) {
                     className="h-10 min-w-0 flex-1 bg-transparent px-3 text-zinc-100 outline-none"
                     onChange={(event) => setValues((current) => ({ ...current, [field.key]: event.target.value }))}
                     min={field.key.startsWith('RESTIC_KEEP_') ? '0' : undefined}
+                    placeholder={field.secret && field.hasValue ? 'gesetzt – leer lassen zum Beibehalten' : undefined}
                     type={inputType(field, secretVisible)}
                     value={values[field.key] || ''}
                   />