Is it permissible to seek mediation to build a shop on shared land if the law prohibits building on a part of it, and is the money earned from this shop lawful if it was built in violation of the law?

The ruling on violating building codes depends on whether the building itself is permissible. If the building is permissible, then there is no harm in seeking mediation to facilitate it. However, if it is not permissible, then it is not allowed to circumvent a law established for the public interest. As for the money earned from the shop, its permissibility depends on the type of activity. If it involves permissible trade, then it is permissible, even if it violates the law, provided the violation is for a public interest. In this case, the profit is lawful because the work itself is legitimate.