feat(domains): Kunden, Kontakte aus AutoDNS mit Zuordnung und Domainliste

- Kunden mit Markierung eigene Firma, Kontakte live aus AutoDNS (seitenweise, 60 s Zwischenspeicher), Zuordnung je System
- Kontakt anlegen (Person/Organisation) und einem oder mehreren Kunden zuordnen, nur mit Verwalten
- Domainliste mit Kunde (ueber den Inhaber-Kontakt), Inhaber, Ablaufdatum, Status; Filter und Gruppierung nach Kunde
- Mandantenschutz-Inventar um die beiden neuen Zugriffspaare ergaenzt

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

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

@@ -122,3 +122,125 @@ export function testDomainsConnection(
     json: { environment },
   });
 }
+
+// --- Kunden, Kontakte und Domains (quick-261008-dts, Aufgabe 2) ----------------
+
+export interface DomainsCustomer {
+  id: string;
+  name: string;
+  isOwnCompany: boolean;
+  /** Zugeordnete Kontakte im AKTIVEN System. */
+  contactCount: number;
+}
+
+export interface DomainsCustomerInput {
+  name: string;
+  isOwnCompany?: boolean;
+}
+
+export type DomainsContactType = 'PERSON' | 'ORG';
+
+export interface DomainsContact {
+  /** AutoDNS-Kontakt-Nummer. */
+  id: number;
+  type: string | null;
+  displayName: string;
+  fname: string | null;
+  lname: string | null;
+  organization: string | null;
+  address: string[];
+  pcode: string | null;
+  city: string | null;
+  country: string | null;
+  email: string | null;
+  phone: string | null;
+  alias: string | null;
+  customerId: string | null;
+  customerName: string | null;
+}
+
+export interface DomainsContactList {
+  environment: DomainsEnvironment;
+  contacts: DomainsContact[];
+  /** Es werden nur die ersten 2000 Eintraege geliefert. */
+  truncated: boolean;
+  fetchedAt: string;
+}
+
+export interface DomainsDomain {
+  name: string;
+  /** ISO-Zeitpunkt oder null. */
+  expire: string | null;
+  /** Rohwert von AutoDNS (`registryStatus`). */
+  status: string | null;
+  cancelationPending: boolean;
+  ownerContactId: number | null;
+  ownerName: string | null;
+  customerId: string | null;
+  customerName: string | null;
+}
+
+export interface DomainsDomainList {
+  environment: DomainsEnvironment;
+  domains: DomainsDomain[];
+  truncated: boolean;
+  fetchedAt: string;
+}
+
+export interface CreateDomainsContactInput {
+  type: DomainsContactType;
+  organization?: string;
+  fname: string;
+  lname: string;
+  /** Anschriftzeilen (Strasse und Hausnummer, optional eine zweite Zeile). */
+  street: string[];
+  pcode: string;
+  city: string;
+  /** Laendercode nach ISO 3166-1 (zwei Grossbuchstaben). */
+  country: string;
+  email: string;
+  phone: string;
+  customerId?: string;
+}
+
+export function listCustomers(): Promise<DomainsCustomer[]> {
+  return request<DomainsCustomer[]>('/customers');
+}
+
+export function createCustomer(input: DomainsCustomerInput): Promise<DomainsCustomer> {
+  return request<DomainsCustomer>('/customers', { method: 'POST', json: input });
+}
+
+export function updateCustomer(id: string, input: DomainsCustomerInput): Promise<DomainsCustomer> {
+  return request<DomainsCustomer>(`/customers/${encodeURIComponent(id)}`, {
+    method: 'PUT',
+    json: input,
+  });
+}
+
+export function deleteCustomer(id: string): Promise<{ deleted: true }> {
+  return request<{ deleted: true }>(`/customers/${encodeURIComponent(id)}`, { method: 'DELETE' });
+}
+
+export function listContacts(opts: { refresh?: boolean } = {}): Promise<DomainsContactList> {
+  return request<DomainsContactList>(`/contacts${opts.refresh ? '?refresh=1' : ''}`);
+}
+
+export function createContact(input: CreateDomainsContactInput): Promise<DomainsContact> {
+  return request<DomainsContact>('/contacts', { method: 'POST', json: input });
+}
+
+/** `customerId: null` loest die Zuordnung. */
+export function assignContacts(
+  contactIds: number[],
+  customerId: string | null,
+): Promise<{ assigned: number; removed: number }> {
+  return request<{ assigned: number; removed: number }>('/contacts/assign', {
+    method: 'POST',
+    json: { contactIds, customerId },
+  });
+}
+
+export function listDomains(opts: { refresh?: boolean } = {}): Promise<DomainsDomainList> {
+  return request<DomainsDomainList>(`/domains${opts.refresh ? '?refresh=1' : ''}`);
+}