South Korea’s bid to reboot ties with China and deepen trade links while strengthening its military alliance with the United States has stirred warnings of renewed pressure from both powers, with last week’s Apec summit underscoring the fragility of Seoul’s balancing act. President Lee Jae-myung’s meetings with his Chinese and American counterparts, Xi Jinping and Donald Trump, have been hailed as diplomatic wins. However, analysts say Seoul could pay a steep price for trying to hedge between...