Does thinking about and planning for the future—such as for study, marriage, and travel—contradict Islamic Sharia, and is it considered a presumptuous act or a form of foretelling what is transient?

Thinking about and preparing for the future does not contradict Sharia; in fact, it may be commanded. What is forbidden is to place all one's attention on this world and neglect the Hereafter. Planning for the future is not fortune-telling, but it must be known that the future of the Hereafter is more worthy of attention than the worldly future.