feat: improve attendance scheduling and API validation

apps/server/src/database/database-migrations.spec.ts

@@ -209,6 +209,28 @@ describe('DatabaseMigrationsService — course attendance schema', () => {
     expect(runner.release).toHaveBeenCalled();
   });
 
+  it('adds the configurable attendance window to existing schedules', async () => {
+    const runner = mockRunner({
+      getTables: [
+        { name: 'class_schedule', columns: [{ name: 'id' }] },
+        { name: 'attendance_records', columns: [{ name: 'id' }] },
+        { name: 'attendance_sessions', columns: [{ name: 'id' }] },
+      ],
+    });
+    runner.getTable.mockImplementation(async (name: string) =>
+      name === 'class_schedule'
+        ? { name, columns: [{ name: 'id' }] }
+        : { name, columns: [{ name: 'id' }, { name: 'schedule_id' }, { name: 'attendance_session_id' }] },
+    );
+    await bootstrapCourseAttendance(runner);
+
+    await service.ensureCourseAttendanceSchema();
+
+    expect(runner.query).toHaveBeenCalledWith(
+      expect.stringContaining('ALTER TABLE class_schedule ADD COLUMN attendance_advance_minutes'),
+    );
+  });
+
   it('creates attendance_sessions with FK RESTRICT constraints when table is missing', async () => {
     const runner = mockRunner({
       getTables: [{ name: 'attendance_records', columns: [{ name: 'id' }] }],