HONG KONG — Hong Kong media tycoon and pro-democracy advocate Jimmy Lai, 76, testified in court for the first time on Wednesday in his landmark national security trial, accused of endangering China’s national security by colluding with foreign forces. Lai was first arrested, under the national security law in August 2020, and has spent much of the time since in prison. He also faces separate sedition charges linked to his newspaper. The prosecution has accused Lai of alleged collusion with foreign forces, which it says included meetings with U.S. officials in Washington during the presidency of Donald Trump, calling for