A door-to-door salesman charged with the stabbing death of a 44-year-old Jackson resident last week told investigators he was acting in self-defense after the other man grabbed him by the collar and twice threatened to kill him, authorities said. The deadly confrontation between the salesman, Michael Tsamas, and Joseph Delgardio was captured on video by a neighbor recording from her bedroom window as well as on the dashboard camera of a man driving on West Veterans Highway near Connor Road, according to a criminal complaint. The stabbing occurred minutes after Delgardio told Tsamas to leave be…