feat: 添加sample示例

Yi.Abp.Net8/sample/Acme.BookStore.Application/Services/TestService.cs

@@ -0,0 +1,18 @@
+using Volo.Abp.Application.Services;
+using Volo.Abp.DependencyInjection;
+
+namespace Acme.BookStore.Application.Services
+{
+    public class TestService : ApplicationService
+    {
+        /// <summary>
+        /// 你好世界
+        /// </summary>
+        /// <param name="name"></param>
+        /// <returns></returns>
+        public string GetHelloWorld(string? name)
+        {
+            return name ?? "HelloWord";
+        }
+    }
+}