实验批量发布现在会创建持久化后台任务，不再在 HTTP 请求里逐项校验和通知。

src/Jiaowu.Api/Domain/Academic/ExamEntities.cs

@@ -20,6 +20,7 @@ public sealed class ExamArrangementJob : EntityBase
     public Guid PlanId { get; set; }
     public Guid? ActivePlanId { get; set; }
     public Guid? RequestedByUserId { get; set; }
+    public string? ProjectIdsJson { get; set; }
     public string? SessionIdsJson { get; set; }
     public bool AssignClassrooms { get; set; }
     public bool AssignInvigilators { get; set; }
@@ -138,6 +139,7 @@ public sealed class ExamPublishJob : EntityBase
     public Guid PlanId { get; set; }
     public Guid? ActivePlanId { get; set; }
     public Guid? RequestedByUserId { get; set; }
+    public string? ProjectIdsJson { get; set; }
     public ExamPublishJobStatus Status { get; set; } = ExamPublishJobStatus.Queued;
     public string? CurrentStep { get; set; }
     public string? ErrorMessage { get; set; }
@@ -148,7 +150,8 @@ public sealed class ExamPublishJob : EntityBase
 public enum ExamPublishJobKind
 {
     FormalExam = 1,
-    MakeupExam = 2
+    MakeupExam = 2,
+    ExperimentProjects = 3
 }
 
 public enum ExamPublishJobStatus