feat(purchase-list): implement loading skeleton and enhance purchase list fetching logic

src/app/core/services/checkout.service.ts

@@ -62,6 +62,20 @@ export class CheckoutService {
     };
   }
 
+  async getPurchases(tenantCode: string, status?: string): Promise<{ data: any[] }> {
+    let url = `${environment.url}tenants/${tenantCode}/compras`;
+    if (status) {
+      url += `?status=${status}`;
+    }
+    const response = await firstValueFrom(
+      this.http.get<{ data: any[] }>(url)
+    );
+    if (!response) {
+      throw new Error('Error al obtener las compras.');
+    }
+    return response;
+  }
+
   async getPurchase(tenantCode: string, purchaseId: string | number): Promise<PurchaseStatusResponse> {
     const response = await firstValueFrom(
       this.http.get<{ data?: PurchaseStatusResponse } | PurchaseStatusResponse>(`${environment.url}tenants/${tenantCode}/compras/${purchaseId}`)