Add an option to disable reflow on window resize

# Description of the new feature/enhancement

There is an issue with zsh and powerlevel10k with some configuration. When you use ruler or/and right segment in powerlevel10k and you resize the window, the content is reflowed and a mess happen in the terminal [as described in the powerlevel10k README](https://github.com/romkatv/powerlevel10k#horrific-mess-when-resizing-terminal-window).



# Proposed technical implementation details (optional)

An option that allow the user to choose between reflowing or truncating (the buffer or on display) the terminal content will solve this problem.

Start by reproducing the resize behavior with zsh and powerlevel10k, using the linked powerlevel10k README for context. Trace the terminal's resize and reflow handling, then determine how an option could select reflowing or truncation; done means the selected behavior is preserved when the window is resized.

Written by the indexing model from the issue text.