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/RoutingRules/index.tsx

@@ -106,6 +106,7 @@ export default function RoutingRulesPage() {
       form.resetFields()
       void qc.invalidateQueries({ queryKey: ['routing-rules'] })
     },
+    onError: (e: Error) => message.error(e.message),
   })
   const update = useMutation({
     mutationFn: async ({ id, v }: { id: number; v: RuleFormValues }) => {
@@ -117,6 +118,7 @@ export default function RoutingRulesPage() {
       form.resetFields()
       void qc.invalidateQueries({ queryKey: ['routing-rules'] })
     },
+    onError: (e: Error) => message.error(e.message),
   })
   const del = useMutation({
     mutationFn: async (id: number) => { await apiClient.delete(`/routing-rules/${id}`) },
@@ -144,7 +146,7 @@ export default function RoutingRulesPage() {
             <span>{backendLabel(id)}</span>
             {h && (
               <Tooltip title={tip}>
-                <Tag color={h.up ? 'green' : 'red'} style={{ margin: 0 }}>{h.up ? 'UP' : 'DOWN'}</Tag>
+                <Tag color={h.up ? 'green' : 'red'} style={{ margin: 0 }}>{h.up ? t('common.up') : t('common.down')}</Tag>
               </Tooltip>
             )}
           </Space>