What is the ruling on building a commercial shop in the mosque courtyard and dedicating its rent to the mosque, given that it is not possible to control the sales within it?

The ruling on the mosque courtyard is to be considered. If it is part of the mosque (like the mosque walls surrounding it), then it is not permissible to open commercial shops in it, due to the Prophet's (peace be upon him) prohibition of buying and selling in the mosque. However, if it is not part of the mosque, then it is permissible. The basic principle is that what is sold must be permissible. If something unlawful is sold, it must be prohibited. If the profits from these shops are spent for the benefit of the mosque, then those in charge of it must conduct a Sharia investigation into what is being sold there.