California nightlife could be getting a lifeline thanks to a new push to keep bars open until 4 a.m. The effort to breathe boozy life back into the state’s struggling downtown comes courtesy of a pair of San Francisco lawmakers who want to let cities create special zones where bars and restaurants can serve drinks until 4 a.m., two hours past the legal closing time. “The nightlife economy is responsible in our state without a doubt for tens of billions of dollars in revenue , hundreds of