HONG KONG — On the first day of unimpeded journey among mainland China and Hong Kong, Olivia Gai was a single of the initially in line.  Crossing the border from the Chinese territory of Hong Kong to the mainland had been a inconvenience given that the get started of the Covid-19 pandemic, necessitating weeks of quarantine. But this time, it was sleek and swift, stated Gai, 27, who is effective in wealth management. As she entered the mainland city of Shenzhen, “I observed two really festive exhibit boards and the team stated I could generate a would like and set it on — so many persons were crafting and using…