King Maha Vajiralongkorn formally endorsed Paetongtarn Shinawatra as Thailand’s new prime minister on Sunday after parliament voted her into office as the country’s youngest prime minister. Paetongtarn’s royal ratification took place at a traditional ceremony after she gained the support of parliament on Friday with an almost two-thirds majority. Paetongtarn, 37, a scion of the powerful Shinawatra clan and head of the ruling Pheu Thai party, will now move to appoint a cabinet. “This mission is a great one and cannot be accomplished by the prime minister alone. I expect to coordinate power amon…