Ayanna Pressley’s meteoric rise and first place finish in Tuesday’s City Council election can be traced to a groundswell of support that in many neighborhoods transcended race and traditional politics, capturing votes from Dorchester to Back Bay. In all, Pressley placed first in more than half of Boston’s 22 wards. She dominated in the African American community, winning 85 percent of the vote in the Roxbury ward that includes Dudley Square. But she also placed first in the section of the city that encompasses much of Jamaica Plain and Roslindale. And Pressley, who is black, took second in largely white West Roxbury, capturing 53 percent of the vote there.