Issues with some keys not being recognized correctly

Some users have reported issues with how the delete and backspace keys behave in certain terminals.
There have been reports of
- backspace inserting `i` rather than deleting a character
- delete not doing anything, specifically in ST

These issues could be fixed by providing alternative keybindings or, in case of DELETE, providing a mouse-based UI element to clear the canvas

Start by reproducing the backspace behavior in the affected terminals and the delete behavior in ST. Trace how terminal key input is handled and compare the available keybinding or mouse-based clearing options. Done means backspace deletes correctly and delete clears the canvas or has an equivalent usable control.

Written by the indexing model from the issue text.