已改成后台“检查并发布”任务，原来的超时主要就是同步逐条校验导致的。

发布接口立即返回 202 Accepted，页面轮询显示检查进度。
校验改为批量读取，减少重复数据库查询。
检查失败保留草稿并显示具体原因；成功后原子完成旧课表归档和新课表发布。
同一学期禁止两个发布任务并发，服务重启后未完成任务会自动恢复。
发布期间锁定编辑、自动排课等冲突操作。
已补齐 SQLite 开发迁移及 MySQL 生产迁移。

src/Jiaowu.Api/Infrastructure/Persistence/AppDbContext.cs

@@ -38,6 +38,8 @@ public sealed class AppDbContext(DbContextOptions<AppDbContext> options)
         Set<TeachingTaskAllowedClassroom>();
     public DbSet<AutomaticScheduleJob> AutomaticScheduleJobs =>
         Set<AutomaticScheduleJob>();
+    public DbSet<SchedulePublishJob> SchedulePublishJobs =>
+        Set<SchedulePublishJob>();
     public DbSet<CourseSelectionRound> CourseSelectionRounds =>
         Set<CourseSelectionRound>();
     public DbSet<CourseSelectionOffering> CourseSelectionOfferings =>
@@ -400,6 +402,24 @@ public sealed class AppDbContext(DbContextOptions<AppDbContext> options)
                 .OnDelete(DeleteBehavior.SetNull);
         });
 
+        builder.Entity<SchedulePublishJob>(entity =>
+        {
+            entity.Property(x => x.CurrentStep).HasMaxLength(200);
+            entity.Property(x => x.ErrorMessage).HasMaxLength(2000);
+            entity.HasIndex(x => x.ActiveAcademicTermId).IsUnique();
+            entity.HasIndex(x => new { x.SchedulePlanId, x.CreatedAt });
+            entity.HasIndex(x => new { x.Status, x.CreatedAt });
+            entity.HasIndex(x => x.RequestedByUserId);
+            entity.HasOne(x => x.SchedulePlan)
+                .WithMany()
+                .HasForeignKey(x => x.SchedulePlanId)
+                .OnDelete(DeleteBehavior.Cascade);
+            entity.HasOne<ApplicationUser>()
+                .WithMany()
+                .HasForeignKey(x => x.RequestedByUserId)
+                .OnDelete(DeleteBehavior.SetNull);
+        });
+
         builder.Entity<CourseSelectionRound>(entity =>
         {
             entity.Property(x => x.Name).HasMaxLength(120);