Add support to view the content of diffs in commits

<img width="312" height="106" alt="Image" src="https://github.com/user-attachments/assets/318eec7d-8d88-43dc-bb80-328c0bb5bc89" />

Screenshot shows example of a list of the files involved in a commit. I would like to make each file that had a diff possible to select with keyboard or click into to see the diff line-by-line. I could push the PR if we're good with that.