Add Lieferungen section with supplier CRUD and delivery create/list.

Wire /lieferung sub-nav (list, neu, lieferanten) to supplier and delivery APIs.

src/api/StorageManager.js

@@ -291,6 +291,8 @@ export class StorageManager extends ApiClient {
     const companyCache = createCache('GET /company', () => this.#loadCompanies());
     const categoryTreeCache = createCache('GET /category/tree', () => this.#loadCategoryTree());
     const posterminalCache = createCache('GET /posterminal', () => this.#loadPosterminals());
+    const supplierCache = createCache('GET /supplier', () => this.#loadSuppliers());
+    const deliveryCache = createCache('GET /delivery', () => this.#loadDeliveries());
 
     Object.defineProperties(this, {
       authMePromise: { get: () => authMeCache.promise },
@@ -324,6 +326,16 @@ export class StorageManager extends ApiClient {
       posterminalPromise: { get: () => posterminalCache.promise },
       updatePosterminal: { value: posterminalCache.update },
 
+      supplierPromise: { get: () => supplierCache.promise },
+      updateSupplier: { value: supplierCache.update },
+      /** Settled GET /supplier list, or undefined. */
+      suppliers: { get: () => supplierCache.value },
+
+      deliveryPromise: { get: () => deliveryCache.promise },
+      updateDelivery: { value: deliveryCache.update },
+      /** Settled GET /delivery list, or undefined. */
+      deliveries: { get: () => deliveryCache.value },
+
       /** Close and reopen GET /api/events (required after selected-company change). */
       reconnectEvents: { value: () => this.#reconnectEvents() },
     });
@@ -444,6 +456,18 @@ export class StorageManager extends ApiClient {
     return requireArray(data.posterminals, 'posterminals');
   }
 
+  async #loadSuppliers() {
+    const data = await this.supplier.list();
+    requireObject(data, 'GET /api/supplier');
+    return requireArray(data.suppliers, 'suppliers');
+  }
+
+  async #loadDeliveries() {
+    const data = await this.delivery.list();
+    requireObject(data, 'GET /api/delivery');
+    return requireArray(data.deliveries, 'deliveries');
+  }
+
   async doSearch({ target, filter, offset, maxCount, onUpdate }) {
     const articles = await this.articleIndexPromise;
     const query = target.trim().toLowerCase();