fix: add Class repo to AttendanceService, fix getClasses API

apps/server/src/attendance/attendance.service.ts

@@ -21,6 +21,8 @@ export class AttendanceService {
     private attendanceRepo: Repository<AttendanceRecord>,
     @InjectRepository(DingAttendanceRaw)
     private dingRawRepo: Repository<DingAttendanceRaw>,
+    @InjectRepository(Class)
+    private classRepo: Repository<Class>,
   ) {}
 
   // ── Batch create attendance records ──
@@ -182,15 +184,19 @@ export class AttendanceService {
 
   // ── Get distinct classes with attendance records ──
   async getClasses() {
-    const qb = this.attendanceRepo
+    const rows = await this.attendanceRepo
       .createQueryBuilder('ar')
-      .leftJoin('ar.class', 'class')
       .select('DISTINCT ar.classId', 'classId')
-      .addSelect('class.name', 'className')
       .where('ar.classId IS NOT NULL')
-      .orderBy('ar.classId', 'ASC');
+      .orderBy('ar.classId', 'ASC')
+      .getRawMany();
 
-    return qb.getRawMany();
+    const classIds = rows.map((r) => r.classId).filter(Boolean) as number[];
+    if (classIds.length === 0) return [];
+
+    const classes = await this.classRepo.find({ where: { id: In(classIds) } });
+    const nameMap = new Map(classes.map((c) => [c.id, c.name]));
+    return classIds.map((id) => ({ classId: id, className: nameMap.get(id) || `班级${id}` }));
   }
 
   // ── DingAttendance raw records ──