The cozy Bonde Fine Wine Shop in Harvard Square seems as if it’s been there for ages, although the store opened less than a year ago. The afternoon sunshine filters through the picture window and brightens the space, while a timeworn, comfy leather chair in one corner makes it tempting to sit and stay awhile. This is what owner Bertil Jean-Chronberg, a master sommelier and restaurateur born in France (a former co-owner of The Beehive, Beat Hotel, and others), invites you to do. He fills this 200-square-foot room with his own particular vibrancy in a one-man quest to teach customers about the bottles he carries: a carefully curated selection of organic, natural, and biodynamically made wines from small producers. “This is my drive, to find wines that limit the impact on the planet,” says Jean-Chronberg. The assemblage comprises what he calls “author wines,” unique types that are unrestrained expressions of the winemaker — all unlike others from their…