Taiwan's envoy to a gathering of Asia-Pacific leaders is the 91-year-old billionaire founder of a computer chip manufacturing giant that operated behind the scenes for decades before being thrust into the centre of US-Chinese tension over technology and security. Morris Chang's hybrid role highlights the clash between Taiwan's status as one of China's top tech suppliers and Beijing's threats to attack the self-ruled island democracy of 22 million people, which the mainland's ruling Communist Party says it part of its territory. Taiwan's decision to send Chang instead of a political leader to the Asia-Pacific Economic Cooperation summit in Thailand reflects…