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/Infrastructure/Timetables/PublishedTimetableProjectionService.cs

@@ -0,0 +1,37 @@
+using Jiaowu.Api.Domain.Academic;
+using Jiaowu.Api.Infrastructure.Persistence;
+using Microsoft.EntityFrameworkCore;
+
+namespace Jiaowu.Api.Infrastructure.Timetables;
+
+public sealed class PublishedTimetableProjectionService(AppDbContext db)
+{
+    public async Task RebuildAsync(SchedulePlan plan, CancellationToken cancellationToken)
+    {
+        var previous = db.PublishedScheduleOccurrences.Where(x => x.SchedulePlanId == plan.Id);
+        db.PublishedScheduleOccurrences.RemoveRange(previous);
+
+        var rows = new List<PublishedScheduleOccurrence>();
+        foreach (var entry in plan.Entries)
+        for (var week = entry.StartWeek; week <= entry.EndWeek; week++)
+        {
+            if (entry.WeekPattern == WeekPattern.Odd && week % 2 == 0 ||
+                entry.WeekPattern == WeekPattern.Even && week % 2 != 0) continue;
+            rows.Add(new PublishedScheduleOccurrence
+            {
+                SchedulePlanId = plan.Id,
+                AcademicTermId = plan.AcademicTermId,
+                ScheduleEntryId = entry.Id,
+                TeachingTaskId = entry.TeachingTaskId,
+                ClassroomId = entry.ClassroomId,
+                Week = week,
+                DayOfWeek = entry.DayOfWeek,
+                StartPeriod = entry.StartPeriod,
+                PeriodCount = entry.PeriodCount,
+                Kind = entry.Kind
+            });
+        }
+        db.PublishedScheduleOccurrences.AddRange(rows);
+        await db.SaveChangesAsync(cancellationToken);
+    }
+}