NYASHA CHINGONO AS dusk descends on the dimly lit central business district of Zimbabwe's capital Harare, a steady stream of home-bound workers flows into a sea of informal traders hawking a mixture of essential foods, clothes and electronic devices. The crowds of night-time street traders have expanded as the southern African country's economic crisis, marked by high inflation and unemployment, pushes people to earn extra cash or look for bargains to make their money go further. Street trading is illegal in Zimbabwe and the traders hope by setting up under cover of darkness they can avoid being spotted by police.…