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/i18n/locales/en/common.json

@@ -367,7 +367,8 @@
       "backup": "Backup",
       "backupHint": "Backup servers receive traffic only when every primary (non-backup) server is down.",
       "empty": "No servers in the pool yet. Click “Add server” to get started.",
-      "deleteConfirm": "Really delete server {{name}}?"
+      "deleteConfirm": "Really delete server {{name}}?",
+      "live": "Live"
     }
   },
   "routing": {
@@ -868,7 +869,10 @@
       "dnssec": "DNSSEC validation",
       "qnameMin": "QName minimisation (privacy)",
       "cacheMin": "Cache min-TTL",
-      "cacheMax": "Cache max-TTL"
+      "cacheMax": "Cache max-TTL",
+      "allIPv4": "all IPv4 interfaces",
+      "allIPv6": "all IPv6 interfaces",
+      "loopback": "Loopback"
     }
   },
   "fwd": {
@@ -934,6 +938,8 @@
     "copied": "Copied",
     "close": "Close",
     "refresh": "Refresh",
+    "up": "UP",
+    "down": "DOWN",
     "relTime": {
       "Xs": "{{n}}s ago",
       "Xm": "{{n}}m ago",