ui: line wraps and horizontal scrolling

Do you have any plans on handling long lines? Currently they are wrapped and there is no horizontal scrolling.
I have added a nowrap argument to textbox Draw in `ktye/ui/tb/textbox.go` that simply pretends to have horizontal space (but the image is smaller). Lines are no longer wrapped but you cannot scroll there.

Start in ktye/ui/tb/textbox.go, where Draw and the proposed nowrap argument are mentioned, and trace how long lines are rendered. Define the expected horizontal scrolling behavior, then verify that long lines neither wrap unexpectedly nor become inaccessible.

Written by the indexing model from the issue text.