refactor(domains): Einstellung Standard-Nameserver entfernt, Doku angepasst (h3t)

- Spalte DomainsConfig.defaultNameServers per Migration 20261008160000 entfernt
- Feld in Einstellungen/Status (API, DTO, Typen) und Karte im Web entfernt
- Anleitungen und CHANGELOG: Nameserver kommen aus AutoDNS

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

apps/web/src/lib/domains-api.ts

@@ -16,7 +16,6 @@ export interface DomainsStatus {
   configured: boolean;
   demoConfigured: boolean;
   liveConfigured: boolean;
-  defaultNameServers: string[];
 }
 
 export interface DomainsEnvironmentAccess {
@@ -29,7 +28,6 @@ export interface DomainsSettings {
   environment: DomainsEnvironment;
   demo: DomainsEnvironmentAccess;
   live: DomainsEnvironmentAccess;
-  defaultNameServers: string[];
   configured: { demo: boolean; live: boolean };
 }
 
@@ -43,7 +41,6 @@ export interface SaveDomainsSettingsInput {
   liveUser?: string;
   livePassword?: string;
   liveContext?: number | null;
-  defaultNameServers?: string[];
 }
 
 export interface ConnectionTestResult {