Looks great for a fresh project so far, thanks for this!

Currently, the data display is still pretty close to the raw data. Having something like a top 10 token usage list for the last turn at the top of the session would help to see if there's anything interesting to investigate for that session.
Similar for sessions overall, i.e. being able to see which sessions have mostly filled context window or compactions so we know which ones are interesting to investigate.