Cops are counting on an ATM video freeze-frame from Amy Lord’s terrifying last morning alive to help them catch the cold-blooded killer who carjacked the beloved 24-year-old, stabbed her to death and dumped the body in a park — an apparently random, broad-daylight attack that horrified young women in South Boston and shocked her western Massachusetts hometown of Wilbraham. The photograph, released by police last night, shows Lord, clad in workout clothes and neon shoes, exiting her black SUV to take money from an ATM — one of five such stops cops say her attacker forced her to make in...