SEOUL, South Korea (AP) - In a sudden shift, North Korea said Saturday that it would consider President Bush's offer of written security assurances in return for dismantling its nuclear weapons programs. Pyongyang had earlier dismissed Bush's offer as laughable and "not worth considering." The abrupt change brightens prospects for restarting talks to ease tensions in the yearlong standoff over North Korea's nuclear programs, which some experts say could produce several more atomic bombs within months. Separately, the Japanese government said North Korea may have test-fired a short-range missile off its eastern coast Saturday. It would be the third suspected...