feat(classes): add schedule and attendance-summary endpoints + frontend tabs

- Add GET /classes/:id/schedule returning ClassSchedule list with classroom name
- Add GET /classes/:id/attendance-summary returning attendance/absence/late rates
- Add 课表 and 出勤汇总 tabs to Classes detail page
- Register ClassSchedule and AttendanceRecord in ClassesModule

apps/server/src/classes/dto/class.dto.ts

@@ -115,3 +115,19 @@ export class AddTeacherDto {
   @IsOptional() @IsString()
   subject?: string;
 }
+
+export class QueryClassScheduleDto {
+  @IsOptional() @IsDateString()
+  startDate?: string;
+
+  @IsOptional() @IsDateString()
+  endDate?: string;
+}
+
+export class QueryClassAttendanceSummaryDto {
+  @IsOptional() @IsDateString()
+  startDate?: string;
+
+  @IsOptional() @IsDateString()
+  endDate?: string;
+}