Actress and future San Francisco first lady Jennifer Siebel has moved a step closer to the altar, having taken up full-time residence in fiance Mayor Gavin Newsom's Russian Hill penthouse, where she is now registered to vote. It turns out, however, that the onetime Republican registered as a member of the American Independent Party - the anti-immigrant, anti-abortion, anti-NAFTA and anti-tax party.San Francisco's election rolls show Siebel cast her ballot using the Green Street address both in November, when Newsom was re-elected, and during February's presidential primary. But because she was affiliated with the American Independent Party, she was ineligible...