CausalTensor is a low-dimensional (up to ~5-25 dimensions recommended) tensor
backed by a single, contiguous Vec<T>. It uses a stride-based memory layout
for efficient, cache-friendly access and manipulation.
CausalTensorWitness is a zero-sized type that acts as a Higher-Kinded Type (HKT) witness
for the CausalTensor<T> type constructor. It allows CausalTensor to be used with generic
functional programming traits like Functor, Applicative, Foldable, and Monad
from the deep_causality_haft crate.