When Lau Kai Fai, his wife and teenage son moved into a new Hong Kong flat last month, he thought the 290 square feet (27 square metres) of space in his “module home” felt like “winning the lottery.”Among the first Hong Kongers to move into such prefabricated dwellings, built as a transition for people awaiting public housing, Lau’s family more than tripled the space they had squeezed into. Now they sit together for meals, rather than eating in turns.While tiny by the standards of many cities…