What is the ruling on imagining a realistic or unrealistic scene and manipulating things within it according to one's desire, and describing it audibly using the five senses, and is describing the taste of an imagined thing as "this is how it tastes" considered a lie or an attempt to know the unseen?

What the questioner mentioned is considered wishful thinking and daydreams. It is the self conversing about what may or may not be, and the soul desiring the attainment of a desired matter. Psychologists have defined it as wishful thinking through which a person achieves gratification for desires and impulses that they are unable to realize in reality. It is an escape from the problems of reality into an imaginary world. A person's thinking about this and uttering it is permissible as long as it does not reach the point of intending to commit something unlawful, and it is not considered divination or claiming knowledge of the unseen.