The Newseum is becoming a breaking news-eum this month as it prepares to exhibit artifacts from the protests and news coverage in Ferguson, Mo., while that story continues to unfold. Sharon Shahid, the Newseum’s online managing editor — call her a deadline curator — was on the ground in the simmering St. Louis suburb shortly before the announcement last week that the grand jury would not indict officer Darren Wilson in the fatal shooting of Michael Brown on Aug. 9. Shahid collected a press pass and two rubber pellet balls from a police stun grenade donated by Stephanie Lecci, a...