Anacostia’s only coffee shop is planning to expand.

Photos by Holly Le Today’s grand opening at Big Chair Coffee n’ Grill might be the most highly anticipated new business event in River East in years. Dozens of curious customers dropped by the soft opening on Saturday to check the place out. There wasn’t a whole lot to see yet: No sign, no food. But before Big Chair even opened its doors, it was already building a scene. Even Ward 8 Councilmember Marion Barry…