Refactor useSessionFileStore. It tracks too much.

We need to separate out some of the things that useSessionFileStore is tracking. It should probably just track files that are sent and returned from front to back and vice versa.

It's also tracking rag data when its returned I feel like that each rag call, description, title, keywords, assays, ect. should all be their own file that is a store after it's rag call is returned.