Hong Kong (AFP) – Waiting at a bus stop on Hong Kong’s border with mainland China, Billy Yiu was preparing to say goodbye to his wife and baby, unsure when he might see them again.The 40-year-old Hong Konger works in the semi-autonomous financial hub and commutes daily from neighbouring Shenzhen, where rents are far cheaper.But the journey will be all but impossible for the foreseeable future.In a bid to halt the spread of a deadly new coronavirus, Hong Kong on Saturday began placing anyone crossing from the mainland under a mandatory 14-day quarantine.So on Thursday night Yiu was making a fin…