Handshakes, taps on the arm, and frequent asides marked the much-awaited meeting between Xi Jinping and Donald Trump on Thursday morning, as the two presidents projected a close rapport during the first full day of Trump’s visit to China. Attention was focused not only on the substance of the high-stakes talks, but also on the personal dynamics between the US and Chinese heads of state – a relationship widely seen as a barometer of the broader diplomatic mood as the world’s two largest economies...