Auto-code study description

Use the abstracts of original studies (in a first step where easily available from crossref via `rcrossref::cr_abstract`) and an LLM to auto-generate 2 sentence summaries of the effect/relationship studied in the paper - either in python using langchain, or in R using ellmer.

Data for original dois: https://github.com/forrtproject/FReD-data/blob/main/Replication%20List/libre2.xlsx

(to be consolidated with #30, but can be worked on independently)