课表查询中最明显的性能优化。

将混合考场查询从“加载整个学期的考场、座位、教师、班级后在内存筛选”，改为在数据库中按班级、教师或教室直接筛选。
改为窄字段投影，避免创建大量 EF 实体和关系对象。
添加查询标签，便于后续在 MySQL 慢查询和链路追踪中定位。
保留现有 HybridCache/可选 Redis 缓存体系，无需新增依赖或数据库迁移。
增加教室、无关教室、监考教师三种回归场景。

tests/Jiaowu.Api.Tests/ExamArrangementServiceTests.cs

@@ -1,6 +1,7 @@
 using Jiaowu.Api.Domain.Academic;
 using Jiaowu.Api.Infrastructure.Exams;
 using Jiaowu.Api.Infrastructure.Persistence;
+using Jiaowu.Api.Infrastructure.Timetables;
 using Microsoft.Data.Sqlite;
 using Microsoft.EntityFrameworkCore;
 
@@ -55,6 +56,48 @@ public sealed class ExamArrangementServiceTests
         Assert.Contains("1个教学班场次处理完成", result.Message);
         Assert.Contains("1名监考教师", result.Message);
         Assert.Contains("程序设计", result.Message);
+
+        plan = await db.ExamPlans.SingleAsync(x => x.Id == plan.Id);
+        plan.Status = ExamPlanStatus.Published;
+        await db.SaveChangesAsync();
+        db.ChangeTracker.Clear();
+
+        var timetableService = new TimetableDataService(db);
+        var classroomTimetable = await timetableService.BuildAsync(
+            TimetableResourceType.Classroom,
+            seed.LargeClassroom.Id,
+            seed.Term.Id,
+            null,
+            false,
+            null,
+            null,
+            CancellationToken.None);
+        var unrelatedClassroomTimetable = await timetableService.BuildAsync(
+            TimetableResourceType.Classroom,
+            seed.SmallClassroom.Id,
+            seed.Term.Id,
+            null,
+            false,
+            null,
+            null,
+            CancellationToken.None);
+        var invigilatorTimetable = await timetableService.BuildAsync(
+            TimetableResourceType.Teacher,
+            room.Invigilators.Single().TeacherId,
+            seed.Term.Id,
+            null,
+            false,
+            null,
+            null,
+            CancellationToken.None);
+
+        Assert.Equal(
+            "程序设计",
+            Assert.Single(classroomTimetable!.ExamEntries).CourseName);
+        Assert.Empty(unrelatedClassroomTimetable!.ExamEntries);
+        Assert.Contains(
+            "监考：监考教师",
+            Assert.Single(invigilatorTimetable!.ExamEntries).TeacherNames);
     }
 
     [Fact]