As Gov. Jerry Brown pushes an international climate-change agenda, he faces a crucial test at home: ensuring that California’s signature program to tackle global warming survives into the next decade. Brown is fighting for a deal this month to extend the state’s cap-and trade program, which forces power plants, factories and refineries to pay to pollute and is set to expire in 2020. It has not come easily. He needs two-thirds of the Senate and Assembly to approve a complex proposal — one sure to have implications not just for planet Earth but also for Californians’ health and pocketbooks.