Source Editor: Add a scroll/don't extend past end of page

I opened this since the original ticket is complete for the source editor card. Also, I wanted to discuss when we should add this.

Here are my thoughts:
Currently the new source editor card sits in the old folder-pane. This means when you select a document in the middle of the screen or further down it opens at the bottom, it's very small so I think it would look funny right now to add the scroll or to make it only show the portion that fits in the screen. Here is how it looks.

Also, I thought I'd do a bit of research and I noticed that for github there is no scroll on the file itself only on the main window. After seeing this I wonder if we want to add the scroll and make it fit in the window after all.
https://github.com/SolidOS/profile-pane/blob/main/src/ProfileView.ts

Wanted to get your thoughts.

Start by reading the linked ProfileView.ts example and inspecting how the source editor card is placed in the folder-pane. Clarify with maintainers whether the desired behavior is scrolling or fitting the visible window, then define the expected behavior for documents opened at different positions. Done means the agreed interaction is implemented and its layout behavior is verified.