Help screen (`?`) is not scrollable on shorter terminals

On terminals shorter than 52 lines, at least part of the help UI is truncated. Using either keyboard (j/k or ↑/↓) or a mouse to try to access the truncated content does not work. For example, with just 33 lines, this is what is visible:

<img width="1293" height="719" alt="Image" src="https://github.com/user-attachments/assets/dfca438b-743a-4bd6-a317-2585669ed832" />