The late-hour fiscal cliff deal, even with all the chaos and unanswered questions, was still enough to send stocks soaring, the first trading day of the new year. The Dow average reached its highest level since Dec. 2011. Technology and bank stocks rose the most. Government bond prices fell as investors pulled money out of safe-harbor investments. But despite the euphoria, many investors cautioned that it can’t last long. The deal merely postpones the country’s budget reckoning, they said, rather than averting it. Also giving US markets a lift Wednesday was a rise in manufacturing in December and an increase in factory hiring.