GOMA, CONGO — Panic spread in eastern Congo’s main city on Thursday, with M23 rebels steadily inching closer to Goma and seizing a nearby town as they battle the Congolese army. Bombs were heard going off in the city’s distant outskirts, and hundreds of wounded civilians were brought in to the main hospital from the area of the fighting. The rebel group has been making significant advances in recent weeks, closing in on Goma, which is home to around 2 million people and a regional hub for security and humanitarian efforts. On Thursday, the rebels took Sake, a town only