fix(i18n): hardkodierte Strings in DNS/RoutingRules/Settings/Backends bereinigen

- DNS Settings: Loopback/allIPv4/allIPv6 Interface-Labels in t() überführt
- RoutingRules: UP/DOWN-Tags + fehlende onError-Handler in create/update
- Settings: t-Variable-Shadowing in top_tables-Map behoben (t → tbl)
- Backends: 'Live'-Spaltenheader → t('backends.server.live')
- common.up/down + dns.settings.allIPv4/allIPv6/loopback in en+de ergänzt

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

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

@@ -442,10 +442,10 @@ function SettingsTab() {
   // Mode "tags" damit der Operator notfalls auch eine IP eintippen kann
   // die der Kernel noch nicht meldet (z.B. eine geplante VIP).
   const ipOptions: { value: string; label: string }[] = []
-  ipOptions.push({ value: '0.0.0.0', label: '0.0.0.0 — alle IPv4-Interfaces' })
-  ipOptions.push({ value: '::',      label: ':: — alle IPv6-Interfaces' })
-  ipOptions.push({ value: '127.0.0.1', label: '127.0.0.1 — Loopback IPv4' })
-  ipOptions.push({ value: '::1',       label: '::1 — Loopback IPv6' })
+  ipOptions.push({ value: '0.0.0.0', label: `0.0.0.0 — ${t('dns.settings.allIPv4')}` })
+  ipOptions.push({ value: '::',      label: `:: — ${t('dns.settings.allIPv6')}` })
+  ipOptions.push({ value: '127.0.0.1', label: `127.0.0.1 — ${t('dns.settings.loopback')} IPv4` })
+  ipOptions.push({ value: '::1',       label: `::1 — ${t('dns.settings.loopback')} IPv6` })
   for (const i of sys ?? []) {
     if (i.ifname === 'lo') continue
     for (const a of i.addr_info ?? []) {