The state’s embattled child welfare agency failed to recognize the danger a Lynn baby and his twin brother were in before the infant was killed last year, allegedly at the hands of his mother’s boyfriend, according to a newly released report from a state watchdog.The murder of 3-month-old Chase Gideika in July 2013 was one of three incidents in which infants under the watch of the Department of Children and Families were severely injured at the hands of their father or a mother’s boyfriend in a three-month span, according to the Office of the Child Advocate.