feat: umfangreiches UI+API-Polish (v1.1.36–1.1.42)

Backend:
- Audit-Log: Search-Endpoint mit ILIKE-Filter (actor/action/subject/date)
- NTP: /ntp/status via chronyc tracking (Stratum, Offset, Quelle)
- System: /service-restart mit Allowlist (haproxy/squid/unbound/chrony/scheduler)
- Domain-Response-Headers + Rate-Limit (Migration 0024)
- Join-Tokens (Migration 0025), Cluster-mTLS, Aggregator-Fan-Out
- apt-Service für Update-Banner (apt-get update + Versionsprüfung)
- Backup-Retry mit exponential backoff (retry_apt 3×)
- publish.sh fail-fast + cleanup-old.sh (max 10 Versionen)

Frontend:
- Audit-Log-Page (/audit) mit Filter + Pagination
- ErrorBoundary an React-Root + Vite build-target festgenagelt (iOS 15+)
- Storage-Schema-Stamp: auto-wipe bei Versions-Mismatch (blank-page-Fix)
- EmptyState-Komponente überall ausgerollt
- SSL: Aggregate-Karte (total/expiring/expired/errors)
- Backups: Aggregate-Karte (letzter Backup/Größe/Fehlschläge 24h) + Backup-Now
- NTP: Sync-Status-Karte (chronyc tracking live)
- Domains: Backend-UP/DOWN-Chip aus HAProxy-Stats
- Backends: HAProxy-Status-Spalte (UP/DEGRADED/DOWN)
- Settings: Service-Neustart-Karte (haproxy/squid/unbound/chrony/scheduler)
- Settings: Upgrade-Status-Card, Wartungsmodus, Auto-Update, Retention
- Dashboard: Recent-Alerts, Cluster-Health, License-Chip, Onboarding-Hint
- System-Regeln im Firewall als eigener Tab

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

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

@@ -1,14 +1,15 @@
 import { useState } from 'react'
 import {
-  Alert, Button, Form, Input, InputNumber, Modal, Select, Space, Switch, Tabs, Tag, Typography, message,
+  Alert, Button, Card, Col, Form, Input, InputNumber, Modal, Row, Select, Space, Statistic, Switch, Tabs, Tag, Tooltip, Typography, message,
 } from 'antd'
 import type { ColumnsType } from 'antd/es/table'
-import { ClockCircleOutlined, DatabaseOutlined, PlusOutlined, SettingOutlined } from '@ant-design/icons'
+import { ClockCircleOutlined, DatabaseOutlined, PlusOutlined, ReloadOutlined, SettingOutlined } from '@ant-design/icons'
 import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query'
 import { useTranslation } from 'react-i18next'
 
 import apiClient, { isEnvelope } from '../../api/client'
 import DataTable from '../../components/DataTable'
+import EmptyState from '../../components/EmptyState'
 import PageHeader from '../../components/PageHeader'
 import ActionButtons from '../../components/ActionButtons'
 import StatusDot from '../../components/StatusDot'
@@ -46,6 +47,24 @@ interface SystemIface {
   addr_info?: Array<{ family: 'inet' | 'inet6'; local: string; prefixlen: number }>
 }
 
+interface NTPStatus {
+  synced: boolean
+  reference?: string
+  stratum?: number
+  offset_ms?: number
+  freq_ppm?: number
+  rms_offset_ms?: number
+  error?: string
+}
+
+async function fetchNTPStatus(): Promise<NTPStatus | null> {
+  try {
+    const r = await apiClient.get('/ntp/status')
+    if (!isEnvelope(r.data)) return null
+    return r.data.data as NTPStatus
+  } catch { return null }
+}
+
 async function listPools(): Promise<Pool[]> {
   const r = await apiClient.get('/ntp/pools')
   if (!isEnvelope(r.data)) return []
@@ -63,6 +82,12 @@ async function listSystemInterfaces(): Promise<SystemIface[]> {
 
 export default function NTPPage() {
   const { t } = useTranslation()
+  const { data: ntpStatus, refetch: refetchStatus } = useQuery({
+    queryKey: ['ntp', 'status'],
+    queryFn: fetchNTPStatus,
+    refetchInterval: 30_000,
+  })
+
   return (
     <div>
       <PageHeader
@@ -70,6 +95,58 @@ export default function NTPPage() {
         title={t('ntp.title')}
         subtitle={t('ntp.intro')}
       />
+
+      <Card
+        size="small"
+        className="mb-12"
+        title={<><ClockCircleOutlined /> {t('ntp.statusCard.title')}</>}
+        extra={<Button size="small" icon={<ReloadOutlined />} onClick={() => refetchStatus()}>{t('common.refresh')}</Button>}
+      >
+        {ntpStatus?.error ? (
+          <Alert type="warning" showIcon message={ntpStatus.error} />
+        ) : ntpStatus ? (
+          <Row gutter={12}>
+            <Col xs={12} sm={6}>
+              <Statistic
+                title={t('ntp.statusCard.sync')}
+                value={ntpStatus.synced ? t('ntp.statusCard.synced') : t('ntp.statusCard.notSynced')}
+                valueStyle={{ color: ntpStatus.synced ? '#16a34a' : '#cf1322', fontSize: 14 }}
+              />
+            </Col>
+            <Col xs={12} sm={6}>
+              <Statistic
+                title={t('ntp.statusCard.source')}
+                value={ntpStatus.reference || '—'}
+                valueStyle={{ fontSize: 13, fontFamily: 'monospace' }}
+              />
+            </Col>
+            <Col xs={12} sm={6}>
+              <Statistic
+                title={t('ntp.statusCard.stratum')}
+                value={ntpStatus.stratum ?? '—'}
+              />
+            </Col>
+            <Col xs={12} sm={6}>
+              <Tooltip title={t('ntp.statusCard.offsetHint')}>
+                <Statistic
+                  title={t('ntp.statusCard.offset')}
+                  value={ntpStatus.offset_ms != null
+                    ? (ntpStatus.offset_ms >= 0 ? '+' : '') + ntpStatus.offset_ms.toFixed(3) + ' ms'
+                    : '—'}
+                  valueStyle={{
+                    fontSize: 13,
+                    color: ntpStatus.offset_ms != null && Math.abs(ntpStatus.offset_ms) > 100
+                      ? '#d48806' : undefined,
+                  }}
+                />
+              </Tooltip>
+            </Col>
+          </Row>
+        ) : (
+          <Typography.Text type="secondary">{t('ntp.statusCard.loading')}</Typography.Text>
+        )}
+      </Card>
+
       <Tabs
         defaultActiveKey="pools"
         items={[
@@ -141,6 +218,11 @@ function PoolsTab() {
     },
   ]
 
+  const openCreate = () => {
+    setCreating(true); form.resetFields()
+    form.setFieldsValue({ kind: 'pool', iburst: true, prefer: false, active: true } as Pool)
+  }
+
   return (
     <>
       <DataTable
@@ -149,13 +231,22 @@ function PoolsTab() {
         dataSource={data ?? []}
         columns={cols}
         extraActions={
-          <Button type="primary" icon={<PlusOutlined />} onClick={() => {
-            setCreating(true); form.resetFields()
-            form.setFieldsValue({ kind: 'pool', iburst: true, prefer: false, active: true } as Pool)
-          }}>
+          <Button type="primary" icon={<PlusOutlined />} onClick={openCreate}>
             {t('ntp.pool.add')}
           </Button>
         }
+        emptyContent={
+          <EmptyState
+            icon={<ClockCircleOutlined />}
+            title={t('ntp.pool.emptyTitle')}
+            description={t('ntp.pool.emptyDesc')}
+            action={
+              <Button type="primary" icon={<PlusOutlined />} onClick={openCreate}>
+                {t('ntp.pool.add')}
+              </Button>
+            }
+          />
+        }
       />
 
       <Modal