新增 PublishedScheduleOccurrences：发布时将周期规则按实际周次展开为只读课次明细。

明细保留课表版本、学期、来源排课条目、教学任务、场地、周次、星期和节次，并建立面向教学任务/周次、课表/场地/周次的索引。
明细在“发布课表”的同一事务内生成；发布失败不会留下半成品。

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

@@ -72,6 +72,23 @@ public sealed class TeachingTaskAllowedClassroom
     public Classroom? Classroom { get; set; }
 }
 
+public sealed class PublishedScheduleOccurrence : EntityBase
+{
+    public Guid SchedulePlanId { get; set; }
+    public Guid AcademicTermId { get; set; }
+    public Guid ScheduleEntryId { get; set; }
+    public Guid TeachingTaskId { get; set; }
+    public Guid? ClassroomId { get; set; }
+    public int Week { get; set; }
+    public int DayOfWeek { get; set; }
+    public int StartPeriod { get; set; }
+    public int PeriodCount { get; set; }
+    public ScheduleEntryKind Kind { get; set; }
+    public ScheduleEntry? ScheduleEntry { get; set; }
+    public TeachingTask? TeachingTask { get; set; }
+    public Classroom? Classroom { get; set; }
+}
+
 public sealed class TeachingTaskAllowedExperimentClassroom
 {
     public Guid TeachingTaskScheduleConstraintId { get; set; }

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

@@ -33,6 +33,7 @@ public sealed class AppDbContext(DbContextOptions<AppDbContext> options)
         Set<TeacherCourseApplication>();
     public DbSet<SchedulePlan> SchedulePlans => Set<SchedulePlan>();
     public DbSet<ScheduleEntry> ScheduleEntries => Set<ScheduleEntry>();
+    public DbSet<PublishedScheduleOccurrence> PublishedScheduleOccurrences => Set<PublishedScheduleOccurrence>();
     public DbSet<ScheduleTimeSlot> ScheduleTimeSlots => Set<ScheduleTimeSlot>();
     public DbSet<TeachingTaskScheduleConstraint> TeachingTaskScheduleConstraints =>
         Set<TeachingTaskScheduleConstraint>();
@@ -539,6 +540,15 @@ public sealed class AppDbContext(DbContextOptions<AppDbContext> options)
                 .HasForeignKey(x => x.ClassroomId)
                 .OnDelete(DeleteBehavior.Restrict);
         });
+        builder.Entity<PublishedScheduleOccurrence>(entity =>
+        {
+            entity.HasIndex(x => new { x.AcademicTermId, x.TeachingTaskId, x.Week });
+            entity.HasIndex(x => new { x.SchedulePlanId, x.ClassroomId, x.Week, x.DayOfWeek, x.StartPeriod });
+            entity.HasIndex(x => new { x.ScheduleEntryId, x.Week }).IsUnique();
+            entity.HasOne(x => x.ScheduleEntry).WithMany().HasForeignKey(x => x.ScheduleEntryId).OnDelete(DeleteBehavior.Cascade);
+            entity.HasOne(x => x.TeachingTask).WithMany().HasForeignKey(x => x.TeachingTaskId).OnDelete(DeleteBehavior.Restrict);
+            entity.HasOne(x => x.Classroom).WithMany().HasForeignKey(x => x.ClassroomId).OnDelete(DeleteBehavior.SetNull);
+        });
 
         builder.Entity<TeachingTaskAllowedExperimentClassroom>(entity =>
         {