WASHINGTON — Doris Cochran, a disabled mother of two young boys, is stockpiling canned foods these days, filling her shelves with noodle soup, green beans, peaches and pears — anything that can last for months or even years. Her pantry looks as though she’s preparing for a winter storm. But she’s just trying to make sure her family won’t go hungry if her food stamps run out. For those like Cochran who rely on federal aid programs, the social safety net no longer feels so safe. As the longest government shutdown in U.S.