[feature]: make sidebar fully resizable (remove minimum percentage of window width)

Is there an existing issue for this?

• I have searched the existing issues

Summary

Sidebar takes too much screen space even in it minimal width (which is always equal to some percentage of the window width). Most time, especially in the vertical layout, it can be shrink down without loosing anything, but winning a lot of space for other panels.

Why should this be worked on?

This make app mode useful on small screens, especially in vertical layout.