A 21st-century gold rush is on in California after the voters approved $3 billion for human embryonic stem cell research. At least one out-of-state biotech company is already making plans to move to California. Stem cell start-up businesses are expected to emerge. And universities are hoping to recruit some of the field’s brightest minds to take part in the biggest state-run research project in U.S. history. The voters’ 59 percent approval of the bond measure on Election Day represents a resounding rejection of Bush administration policy, which has sharply restricted federal funding for research that involves the destruction of human embryos.