What is the ruling on always rolling up clothes to avoid letting them hang below the ankles (isbal), and does that fall under detestability (karahah)? And what is the ruling on permanently folding and sewing clothes for the same purpose?

There is no harm in folding or cutting and sewing the part of the garment that extends below the ankles, for the important thing is that the clothes are not lower than the ankles. And whoever raises his garment by any means to the ankles or above them, there is no harm upon him. The saying of the Prophet, may Allah’s prayers and peace be upon him: "Whatever is below the ankles is in the Fire," indicates the permissibility of what is at the ankles or above them.