HONG KONG—Hong Kong will tighten COVID-19 restrictions despite a lack of local outbreaks to better align with China’s policies and increase chances of quarantine-free travel between the territory and mainland, leader Carrie Lam said Tuesday. It will step up contact tracing, such as requiring the use of its LeaveHomeSafe app in government premises to record the coming and going of visitors. It will also tighten quarantine rules to exempt only emergency workers or those in essential industries such as logistics. Currently, those exempt from quarantine include airline crew, banking and insurance executives, directors of public companies, as well as crew members on cargo and passenger ships, among others. Hong Kong has not had a major local outbreak since the beginning of the year, with virtually no local transmission in recent months. But it is largely closed to international travel, and travelers from countries deemed high-risk such as the United States …