Halcyon’s reach extends across the District. By The People, the citywide festival that the nonprofit is launching this weekend, may be unprecedented here. Neko Case and Ray LaMontagne opened the festival on Wednesday night with a concert at The Anthem. Most of the Smithsonian Institution’s museums plan to stay open until midnight on Saturday for a solstice party coordinated with Halcyon. While the national acts and federal venues are impressive, all weekend long, visual artists from D.C. will anchor the main tents and dozens of satellites on the By The People calendar. That’s unheard of.