Another new watchword for Chinese capitalists is “ common prosperity ,” or a more equitable distribution of wealth. Shortly after Mr. Xi endorsed the theme in August, Alibaba committed $15.5 billion to “common prosperity” goals. A few weeks later, the company’s chief executive, Daniel Zhang, added “common prosperity” to Alibaba’s “ core corporate responsibilities .” One way Alibaba says it is playing its part is by offering more support to the small businesses in China that sell on its platforms. Wei Wei, 35, is a co-founder of Beats Per Minute 120, a brand of colorfully patterned socks. For small sellers…