EPH parameterisations

Hi,

In the README file, I noticed a mention of an upcoming feature: “Create EPH parameterisations based on Nikita Medvedev's data.” I would like to ask whether it is possible to use Nikita Medvedev's data with the current model.

I found these Ce and kappa_e data from: [here](https://github.com/N-Medvedev/XTANT-3_coupling_data/tree/main), and I will convert the units before I apply those data with the current model.

Start with the README note about creating EPH parameterisations and review the linked XTANT-3 coupling data for Ce and kappa_e. Then inspect how the current model accepts parameter data and determine whether converted values can be used; the work is complete when compatibility or the required support is clearly established.

Written by the indexing model from the issue text.