Debussy’s Sonata in G minor opened the program: his last completed work, signed “Musicien français,” composed as he lay dying in wartime Paris, its continuous-variation writing looking backward to Couperin and Rameau rather than forward to Romantic bravura. Josefowicz played it with her entire body, the melodic line’s slow unspooling as much danced as bowed, the finale’s tumultuous joy registering as gesture before it registered as sound.