Understanding the interior dynamics of gas giants like Jupiter and Saturn has long been a focus of planetary science. These planets exhibit prominent east-west banded structures, called zonal winds, clearly visible through telescopes and spacecraft observations. A central question is whether these wind patterns extend into the deep interior and, if so, to what extent and strength. Recent satellite missions to Jupiter (Juno, 2016) and Saturn (Cassini Grand Finale, 2017) measured the gravita...