China’s surprise devaluation of the yuan last month helped trigger currency declines worldwide and increased speculation about Hong Kong’s willingness to keep putting up with such pain. In the options market, bets on an end to the peg jumped to their highest in more than a decade. On his blog in late August, Hong Kong Financial Secretary John Tsang warned that the economy may slow from the 2.6 percent growth rate it managed in the first half of the year. “Hong Kong still needs to face the challenges brought by the fluctuating financial markets, weak foreign trade, and slower tourism,” he wrote.