Sun is not the first thing you expect walking into Donohue’s. Maybe the last. But the light-dappled dining room, with its large windows and adjoining porch, is the new Donohue’s, the beach-house Donohue’s, a country cousin to the city elder. Even Maureen Donohue-Peters, Donohue’s third-generation owner, looks a little different out here in a pink psychedelic-print Pucci-style blouse. Last summer, she opened Donohue’s East in Westhampton Beach. Had she gone a little Hamptons herself?