limits = {row['id']: row['max_chars'] for row in data['channels']}
check('每条文案均保留全部指定事实', all(all(literal in row['text'] for literal in ['蓝杯', '99元', '2026-10-30', '20']) for row in output['copies']))
check('渠道ID与长度符合各自限制', {row['channel'] for row in output['copies']} == set(limits) and all(len(row['text']) <= limits[row['channel']] for row in output['copies']))
save_csv(folder / 'channel-copies.csv', output['copies'])
