It was Christmas Eve 2024 and 19-year-old Chloe Cheung was lying in bed at home in Leeds when she found out the Chinese authorities had put a bounty on her head. As she scrolled through Instagram looking at festive songs, a stream of messages from old school friends started coming into her phone. Look at the news, they told her. Media outlets across east Asia were reporting that Cheung, who had just finished her A-levels, had been declared a threat to national security by officials in Hong Kong. There was…