refactor(workflow): 优化工作流引擎代码结构

- 将ZyFlowVariable实例化语法简化为对象初始化器
- 修正附件路径组合逻辑，从当前目录切换到基础目录
- 移除不必要的wwwroot前缀并改进路径构建方式

OpenAuth.App/WorkflowEngineApp.cs

@@ -129,9 +129,9 @@ public class WorkflowEngineApp : SqlSugarBaseApp<SysCategoryType, SugarDbContext
             var attachmentPaths = SaveAttachments(requestDto.Attachments);
             var flowVariables = new List<ZyFlowVariable>
             {
-                new ZyFlowVariable { InstanceId = instanceId, VarKey = "Title", VarValue = requestDto.Title },
-                new ZyFlowVariable { InstanceId = instanceId, VarKey = "AttachmentPaths", VarValue = attachmentPaths },
-                new ZyFlowVariable
+                new() { InstanceId = instanceId, VarKey = "Title", VarValue = requestDto.Title },
+                new() { InstanceId = instanceId, VarKey = "AttachmentPaths", VarValue = attachmentPaths },
+                new()
                 {
                     InstanceId = instanceId, VarKey = "SubmitTime",
                     VarValue = DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss")
@@ -862,7 +862,8 @@ public class WorkflowEngineApp : SqlSugarBaseApp<SysCategoryType, SugarDbContext
             return string.Empty;
 
         // 定义附件存储目录
-        var uploadDir = Path.Combine(Directory.GetCurrentDirectory(), "wwwroot/Attachments/FlowAttachments");
+        var uploadDir = Path
+            .Combine(AppContext.BaseDirectory, "Attachments/FlowAttachments");
         if (!Directory.Exists(uploadDir))
             Directory.CreateDirectory(uploadDir);