MOSCOW—A Moscow court on Tuesday ordered Russian opposition leader Alexei Navalny to more than 2 1/2 years in prison on charges that he violated the terms of his probation while he was recuperating in Germany from nerve-agent poisoning. Navalny, who is the most prominent critic of President Vladimir Putin, had earlier denounced the proceedings as a vain attempt by the Kremlin to scare millions of Russians into submission. The prison sentence stems from a 2014 embezzlement conviction that he has rejected as fabricated. The 44-year-old Navalny was arrested Jan. 17 upon returning from his five-month convalescence in Germany from the attack, which he has blamed on the Kremlin. Russian authorities deny any involvement. Despite tests by several European labs, Russian authorities said they have no proof he was poisoned. As the order was read, Navalny pointed to his wife Yulia in the courtroom and traced the outline of a heart …