Add sources up to March 30, including OpenAlex v2 update, and delete works that did not transition from v1 and v2

Do one-time shuffle of document codes so that it reflect insertion order, making it Xet friendly, and add sources up to Sept 30

Add .gitignore with the intermediate output, index/untuned.json

Add empty.faiss and reduced ids.parquest

Fix mistakes in README.md

Fill out README.md

Update trained index because Stella doesn't use truncated vectors, cut cluster count to save memory (normalized, OPQ96_384,IVF65536,PQ96)

Add trained index to hopefully its final place (truncated to length-384, normalized, OPQ96,IVF131072,PQ96)

Update .gitattributes

initial commit