feat(cli): Stammdaten-TUI mit Master Data API-Anbindung

- Neue Screens: Kategorien, Lieferanten, Artikel, Kunden (jeweils
  Liste, Detail, Anlegen + Detailaktionen wie Bewertung, Zertifikate,
  Verkaufseinheiten, Lieferadressen, Präferenzen)
- API-Client: Resources für alle 4 Stammdaten-Aggregate implementiert
  (categories, suppliers, articles, customers) mit Mapping von
  verschachtelten Domain-VOs auf flache DTOs
- Lieferant, Artikel, Kategorie: echte HTTP-Calls gegen Backend
  (/api/suppliers, /api/articles, /api/categories, /api/customers)
- 204-No-Content-Endpoints (removeSalesUnit, removeSupplier,
  removeCertificate, removeDeliveryAddress, removeFrameContract)
  lösen Re-Fetch des Aggregats aus
- MasterdataMenu, Navigation-Erweiterung, App.tsx-Routing

frontend/packages/api-client/src/index.ts

@@ -18,6 +18,10 @@ export type { TokenProvider } from './token-provider.js';
 export { createAuthResource } from './resources/auth.js';
 export { createUsersResource } from './resources/users.js';
 export { createRolesResource } from './resources/roles.js';
+export { createCategoriesResource } from './resources/categories.js';
+export { createSuppliersResource } from './resources/suppliers.js';
+export { createArticlesResource } from './resources/articles.js';
+export { createCustomersResource } from './resources/customers.js';
 export {
   ApiError,
   AuthenticationError,
@@ -41,11 +45,64 @@ export type {
   UsersResource,
 } from './resources/users.js';
 export type { RolesResource } from './resources/roles.js';
+export type {
+  ProductCategoryDTO,
+  CreateCategoryRequest,
+  UpdateCategoryRequest,
+  CategoriesResource,
+} from './resources/categories.js';
+export type {
+  SupplierDTO,
+  SupplierStatus,
+  AddressDTO,
+  ContactInfoDTO,
+  PaymentTermsDTO,
+  QualityCertificateDTO,
+  SupplierRatingDTO,
+  CreateSupplierRequest,
+  UpdateSupplierRequest,
+  RateSupplierRequest,
+  AddCertificateRequest,
+  RemoveCertificateRequest,
+  SuppliersResource,
+} from './resources/suppliers.js';
+export type {
+  ArticleDTO,
+  ArticleStatus,
+  SalesUnitDTO,
+  Unit,
+  PriceModel,
+  CreateArticleRequest,
+  UpdateArticleRequest,
+  AddSalesUnitRequest,
+  UpdateSalesUnitPriceRequest,
+  ArticlesResource,
+} from './resources/articles.js';
+export { UNIT_LABELS, PRICE_MODEL_LABELS } from './resources/articles.js';
+export type {
+  CustomerDTO,
+  CustomerType,
+  CustomerStatus,
+  CustomerPreference,
+  DeliveryRhythm,
+  DeliveryAddressDTO,
+  FrameContractDTO,
+  ContractLineItemDTO,
+  CreateCustomerRequest,
+  UpdateCustomerRequest,
+  AddDeliveryAddressRequest,
+  CustomersResource,
+} from './resources/customers.js';
+export { CUSTOMER_PREFERENCE_LABELS, DELIVERY_RHYTHM_LABELS } from './resources/customers.js';
 
 import { createApiClient } from './client.js';
 import { createAuthResource } from './resources/auth.js';
 import { createUsersResource } from './resources/users.js';
 import { createRolesResource } from './resources/roles.js';
+import { createCategoriesResource } from './resources/categories.js';
+import { createSuppliersResource } from './resources/suppliers.js';
+import { createArticlesResource } from './resources/articles.js';
+import { createCustomersResource } from './resources/customers.js';
 import type { TokenProvider } from './token-provider.js';
 import type { ApiConfig } from '@effigenix/config';
 
@@ -63,6 +120,10 @@ export function createEffigenixClient(
     auth: createAuthResource(axiosClient),
     users: createUsersResource(axiosClient),
     roles: createRolesResource(axiosClient),
+    categories: createCategoriesResource(axiosClient),
+    suppliers: createSuppliersResource(axiosClient),
+    articles: createArticlesResource(axiosClient),
+    customers: createCustomersResource(axiosClient),
   };
 }