China investors are counting on the summit between Xi Jinping and Donald Trump to deliver just enough to sustain the detente trade underpinning stocks and the yuan.Rather than betting on a sweeping reset in relations, market watchers are focused on whether the two leaders can avoid renewed friction on trade, technology and geopolitics. Even without major breakthroughs on those key issues, a broadly constructive outcome is seen keeping the positive market sentiment intact.Such cautious optimism has investors choosing tactical rather than structural bets on Chinese assets, which have gained since the two sides reached a trade truce in South Korea...