Editor’s Note: Sign up for CNN’s Meanwhile in China newsletter which explores what you need to know about the country’s rise and how it impacts the world. Hong Kong CNN — China’s wobbly economy has affected the world’s largest annual shopping event, and companies have launched an aggressive price war to woo customers. The Singles Day festival, also known as “Double 11,” was created by Alibaba in 2009 and has turned into a weeks-long shopping bonanza in China. It regularly racks up more sales than Black Friday and Cyber Monday combined, and is seen as a bellwether of consumers’ willingness…