What is the ruling on a thief apprehended inside a house attempting to steal before taking possession of anything, and can the minimum threshold for theft (nisab) change with varying places, times, and customs?

The religiously-defined theft is: "Taking respected property belonging to another, removing it from its secure place, without any doubt (of ownership), and covertly." Therefore, whoever enters a house and is apprehended before taking anything is not considered a thief and the hadd punishment for theft is not applied to him. Rather, he is punished by ta'zir for the transgression of entering another's house without permission. Attempting prohibited acts that mandate hadd punishments without completing them does not necessitate the hadd, but rather ta'zir if it involved committing a prohibited act. The majority of jurists prevent the application of the hadd if the theft was not completed, and they mandate ta'zir for the attempt, not considering it an attempt at theft, but rather for committing a transgression that necessitates ta'zir. Jurists did not concern themselves with developing a specific theory for attempt; because it is not punished by hadd or qisas, but rather by ta'zir, and the rules of ta'zir are sufficient to govern attempted crimes. Ta'zir is applied to every transgression for which there is no prescribed hadd or expiation.