Include shape in array types

Using [nptyping and beartype](https://github.com/ramonhagenaars/nptyping/blob/master/USERDOCS.md#Quickstart) we can pin down the dimensions that we accept. For instance, the constructor of `ValuationResult` can only accept 1D arrays but we don't enforce that.

Alternatively, [jaxtyping](https://github.com/patrick-kidger/jaxtyping) supports jax, torch and numpy in one go. But python 3.9 is required so we'd have to wait until EOL for 3.8 at the very least.

Are there any other libraries?

Look at the ValuationResult constructor to see how it currently handles arrays. Research nptyping and jaxtyping for shape enforcement. Check Python version constraints and project dependencies. Determine how to integrate a typing library to enforce 1D array dimensions in the constructor.

Written by the indexing model from the issue text.