Yuki Zhang, a 24-year-old student from the Chinese mainland, came to Hong Kong in August 2019 amid increasingly violent anti-government protests. She hoped that during her time studying in the city she could also play a role in resolving conflicts between people from the city with those from across the border. She says the coronavirus pandemic that originated in the central Chinese city of Wuhan only added layers of tension and uncertainty to mainlanders' already complex relationships with…