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/Networks/Interfaces.tsx

@@ -1,10 +1,11 @@
 import { useState } from 'react'
 import { Button, Card, Form, Input, InputNumber, Modal, Select, Space, Switch, Tag, Tooltip, Typography, message } from 'antd'
 import type { ColumnsType } from 'antd/es/table'
-import { PlusOutlined } from '@ant-design/icons'
+import { ClusterOutlined, PlusOutlined } from '@ant-design/icons'
 import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query'
 import { useTranslation } from 'react-i18next'
 import DataTable from '../../components/DataTable'
+import EmptyState from '../../components/EmptyState'
 import ActionButtons from '../../components/ActionButtons'
 import StatusDot from '../../components/StatusDot'
 
@@ -149,6 +150,11 @@ export default function InterfacesTab() {
     },
   ]
 
+  const openCreate = () => {
+    setCreating(true); form.resetFields()
+    form.setFieldsValue({ type: 'ethernet', role: 'lan', active: true })
+  }
+
   return (
     <div>
       <Card title={t('networks.systemDiscovered')} className="mb-12" size="small">
@@ -172,13 +178,22 @@ export default function InterfacesTab() {
         dataSource={ifs ?? []}
         columns={columns}
         extraActions={
-          <Button type="primary" icon={<PlusOutlined />} onClick={() => {
-            setCreating(true); form.resetFields()
-            form.setFieldsValue({ type: 'ethernet', role: 'lan', active: true })
-          }}>
+          <Button type="primary" icon={<PlusOutlined />} onClick={openCreate}>
             {t('networks.addInterface')}
           </Button>
         }
+        emptyContent={
+          <EmptyState
+            icon={<ClusterOutlined />}
+            title={t('networks.emptyTitle')}
+            description={t('networks.emptyDesc')}
+            action={
+              <Button type="primary" icon={<PlusOutlined />} onClick={openCreate}>
+                {t('networks.addInterface')}
+              </Button>
+            }
+          />
+        }
       />
 
       <Modal