fix dimensionality error when switching from one model to the other and using the same document

fix another regression

fix regression

fix condition to establish when we need to cleanup the storage

more constraints on the memory

trying ot harness the model to avoid hallucinating due to the chat memory

cleanup and update documentation

Merge branch 'main' into fix-conversational-memory

fix signature

re-implement the conversational memory access

fix signature

change from year to publication year

include title, authors and year in the data store

cosmetics

fix chroma embeddings when an already seen file is uplaoded

fix env variables (#9)

fix engine to deal with the latest chroma

fix import, and reformat

Setuptools build, pypy release, github action improvements (#5)