fix: sidebar title padding to prevent scrollbar edge case

[ryanwyler]

Summary

Fixes an edge case bug where the sidebar session title causes a visual glitch when the scrollbar activates.

Problem

When the session title is exactly the right character length to fill the sidebar width, it triggers the scrollbar to appear at a precise moment during rendering. This causes mouse drag events to incorrectly propagate to list items below, resulting in unexpected highlighting/selection behavior.

Solution

Added paddingRight={1} to the session title box to ensure there's always room reserved for the scrollbar, preventing the timing edge case.

Testing

Tested with session titles of various lengths including the exact edge case length that triggered the bug.