已修改完成，同时解决了“考生名单都是 0 人”的根因。

考生范围统一为“行政班关联学生 + 已选课学生”，并自动去重；考场分配、人数显示、冲突检测、学生考试安排均使用同一口径。[TeachingTaskRosterQuery.cs (line 40)](E:/jiaowu/src/Jiaowu.Api/Infrastructure/Teaching/TeachingTaskRosterQuery.cs:40)
新增考场签名单 Excel 导出接口。[ExamsController.cs (line 568)](E:/jiaowu/src/Jiaowu.Api/Controllers/ExamsController.cs:568)
考试计划页面新增“导出考场签名单”按钮。[ExamsView.vue (line 255)](E:/jiaowu/web/src/views/ExamsView.vue:255)
工作簿包含“考场汇总”以及每个考试场次独立的 A4 签到表，字段包括座位号、学号、姓名、行政班、考生签名和备注。[ExamSignInWorkbookExporter.cs (line 12)](E:/jiaowu/src/Jiaowu.Api/Infrastructure/Exams/ExamSignInWorkbookExporter.cs:12)
未分配考场或监考教师时，也能导出并显示“待分配”。

tests/Jiaowu.Api.Tests/ExamArrangementServiceTests.cs

@@ -48,6 +48,7 @@ public sealed class ExamArrangementServiceTests
             .SingleAsync(x => x.Id == untouched.Id);
         Assert.True(result.Success);
         Assert.NotNull(persistedSelected.ClassroomId);
+        Assert.Equal(seed.LargeClassroom.Id, persistedSelected.ClassroomId);
         Assert.Null(persistedUntouched.ClassroomId);
         Assert.Single(persistedSelected.Invigilators);
         Assert.Empty(persistedUntouched.Invigilators);
@@ -159,6 +160,27 @@ public sealed class ExamArrangementServiceTests
             BuildingId = building.Id,
             Capacity = 80
         };
+        var smallClassroom = new Classroom
+        {
+            Code = $"R-SMALL-{suffix}",
+            Name = "102",
+            BuildingId = building.Id,
+            Capacity = 1
+        };
+        var major = new Major
+        {
+            Code = $"MAJOR-{suffix}",
+            Name = "计算机科学与技术",
+            CollegeId = college.Id,
+            DegreeType = "工学学士"
+        };
+        var administrativeClass = new AdministrativeClass
+        {
+            Code = $"CLASS-{suffix}",
+            Name = "计科 2026-1 班",
+            MajorId = major.Id,
+            Grade = 2026
+        };
         var firstCourse = new Course
         {
             Code = $"COURSE-1-{suffix}",
@@ -177,7 +199,14 @@ public sealed class ExamArrangementServiceTests
             Name = "程序设计教学班",
             AcademicTermId = term.Id,
             CourseId = firstCourse.Id,
-            Status = TeachingTaskStatus.Published
+            Status = TeachingTaskStatus.Published,
+            Classes =
+            [
+                new TeachingTaskClass
+                {
+                    AdministrativeClassId = administrativeClass.Id
+                }
+            ]
         };
         var secondTask = new TeachingTask
         {
@@ -201,6 +230,25 @@ public sealed class ExamArrangementServiceTests
             college,
             building,
             classroom,
+            smallClassroom,
+            major,
+            administrativeClass,
+            new Student
+            {
+                StudentNumber = $"STUDENT-1-{suffix}",
+                Name = "学生甲",
+                AdministrativeClassId = administrativeClass.Id,
+                EnrollmentYear = 2026,
+                EnrollmentDate = new DateOnly(2026, 9, 1)
+            },
+            new Student
+            {
+                StudentNumber = $"STUDENT-2-{suffix}",
+                Name = "学生乙",
+                AdministrativeClassId = administrativeClass.Id,
+                EnrollmentYear = 2026,
+                EnrollmentDate = new DateOnly(2026, 9, 1)
+            },
             firstCourse,
             secondCourse,
             firstTask,
@@ -223,11 +271,12 @@ public sealed class ExamArrangementServiceTests
                 EndsAt = new TimeOnly(9, 50)
             });
         await db.SaveChangesAsync();
-        return new SeedData(term, firstTask, secondTask);
+        return new SeedData(term, firstTask, secondTask, classroom);
     }
 
     private sealed record SeedData(
         AcademicTerm Term,
         TeachingTask FirstTask,
-        TeachingTask SecondTask);
+        TeachingTask SecondTask,
+        Classroom LargeClassroom);
 }