feat: add class roster export and attendance stats export

- GET /classes/:id/roster/export — Excel export with 姓名/学号/加入日期/状态
- GET /attendance-records/export — Excel export with 姓名/班级/日期/时段/状态/来源/备注/打卡时间
- Add findAllForExport to AttendanceService (no pagination)
- Both use ExcelJS following classrooms controller downloadTemplate pattern

apps/server/src/classes/classes.controller.ts

@@ -9,7 +9,9 @@ import {
   Query,
   UseGuards,
   Request,
+  Res,
 } from '@nestjs/common';
+import type { Response } from 'express';
 import { ClassesService } from './classes.service';
 import {
   CreateClassDto,
@@ -22,6 +24,7 @@ import { JwtAuthGuard } from '../auth/guards/jwt-auth.guard';
 import { OperationLogsService } from '../operation-logs/operation-logs.service';
 import { extractRequestInfo } from '../common/request-utils';
 import { RequirePermission } from '../auth/decorators/permission.decorator';
+import * as ExcelJS from 'exceljs';
 
 @UseGuards(JwtAuthGuard)
 @Controller('classes')
@@ -103,6 +106,44 @@ export class ClassesController {
     return result;
   }
 
+  @Get(':id/roster/export')
+  @RequirePermission('class:view')
+  async exportRoster(@Param('id') id: string, @Res() res: Response) {
+    const classEntity = await this.service.findOne(+id);
+    const classStudents = await this.service.getStudents(+id);
+
+    const workbook = new ExcelJS.Workbook();
+    const ws = workbook.addWorksheet('班级花名册');
+    ws.columns = [
+      { header: '姓名', key: 'name', width: 15 },
+      { header: '学号', key: 'studentNo', width: 15 },
+      { header: '加入日期', key: 'joinDate', width: 15 },
+      { header: '状态', key: 'status', width: 10 },
+    ];
+    ws.getRow(1).font = { bold: true };
+    ws.getRow(1).fill = { type: 'pattern', pattern: 'solid', fgColor: { argb: 'FFE0E0E0' } };
+
+    for (const cs of classStudents) {
+      ws.addRow({
+        name: cs.student?.name || '',
+        studentNo: cs.student?.idNumber || '',
+        joinDate: cs.joinDate || '',
+        status: cs.status || '',
+      });
+    }
+
+    res.setHeader(
+      'Content-Type',
+      'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
+    );
+    res.setHeader(
+      'Content-Disposition',
+      `attachment; filename=${encodeURIComponent(`班级花名册-${classEntity.name}`)}.xlsx`,
+    );
+    await workbook.xlsx.write(res);
+    res.end();
+  }
+
   @Get(':id/students')
   @RequirePermission('class:view')
   getStudents(@Param('id') id: string) {