What is the ruling of Sharia on offering consultations regarding currency trading via a website to clients, some of whom may be non-Muslims dealing in usury, given that the work is limited to consultations only, for which a fee is charged, and the Islamic conditions for dealing have been clarified?

It is permissible to provide financial consultations to a disbeliever according to Sharia guidelines, but it is not permissible to assist someone who is known to be embarking on a forbidden transaction. There is no obligation to investigate the consultant's situation; rather, it suffices to refrain from providing consultation to anyone who explicitly states a forbidden transaction or for whom it is highly probable, such as someone seeking advice on borrowing from an interest-based bank.