As they have for several years, the Red Sox will celebrate the life of Jackie Robinson on the occasion of his birthday Thursday (he would have been 94), and the pioneering Hall of Famer’s son will be here to lend a hand. Former Sox player Tommy Harper and storyteller Dick Flavin will join David Robinson and others at Rogers Middle School in Hyde Park and McCormack Middle School in Dorchester. Lexington resident Steve Schlein, who met Jackie Robinson as a kid and became something of a Robinson scholar, will also be there. In 1947, Robinson became the first African-American to play in the major leagues. He’s also the subject of a new movie, “42 ” (his number), directed by Brian Helgeland and starring Chadwick Boseman and Harrison Ford. The film opens in April.