fix(i18n): hardkodierte Strings in Cluster/Users/Backups/Alerts bereinigen

- Cluster: statusTag() bekommt t-Parameter; Status-Labels (online/offline/
  joining/leaving/unknown) → cluster.status.* Keys
- Users: 'You'-Tag → t('users.you') / de: 'Ich'
- Backups: 'OK'-Status-Tag → t('backups.okTag')
- Alerts: Kanal-Kind-Labels + alle SMTP-Formular-Labels in t() überführt
- en/de: cluster.status.*, users.you, backups.okTag, alerts.smtp.*,
  alerts.kindWebhook/kindEmail ergänzt

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

management-ui/src/pages/Cluster/index.tsx

@@ -82,13 +82,13 @@ interface CertStatus {
   peer?: CertInfo
 }
 
-function statusTag(s: HANode['status']) {
+function statusTag(s: HANode['status'], t: (k: string) => string) {
   switch (s) {
-    case 'online':  return <Tag color="green">online</Tag>
-    case 'offline': return <Tag color="red">offline</Tag>
-    case 'joining': return <Tag color="blue">joining</Tag>
-    case 'leaving': return <Tag color="orange">leaving</Tag>
-    default:        return <Tag>unknown</Tag>
+    case 'online':  return <Tag color="green">{t('cluster.status.online')}</Tag>
+    case 'offline': return <Tag color="red">{t('cluster.status.offline')}</Tag>
+    case 'joining': return <Tag color="blue">{t('cluster.status.joining')}</Tag>
+    case 'leaving': return <Tag color="orange">{t('cluster.status.leaving')}</Tag>
+    default:        return <Tag>{t('cluster.status.unknown')}</Tag>
   }
 }
 
@@ -208,7 +208,7 @@ export default function ClusterPage() {
     },
     {
       title: t('cluster.col.status'), dataIndex: 'status', width: 110,
-      render: (s: HANode['status']) => statusTag(s),
+      render: (s: HANode['status']) => statusTag(s, t),
     },
     { title: t('cluster.col.role'), dataIndex: 'role', width: 110,
       render: (v: string) => <Tag color={v === 'primary' ? 'gold' : 'default'}>{v}</Tag> },
@@ -324,7 +324,7 @@ export default function ClusterPage() {
               </Space>
             </Descriptions.Item>
             <Descriptions.Item label={t('cluster.col.status')}>
-              {statusTag(data.local_node.status)}
+              {statusTag(data.local_node.status, t)}
             </Descriptions.Item>
             <Descriptions.Item label={t('cluster.col.role')}>
               <Tag color={data.local_node.role === 'primary' ? 'gold' : 'default'}>