1.3.2: Minor bug fixes + theming improvements

For Firefox version 128

Features:
- Added example of how to install using home-manager & Nix flakes
- Theme Sidebar header (not done yet)

Fixes:
- Apply uc radius to navbar icons
- Apply uc radius and custom color to urlbar icons
- Animations of sidebar
- Small tweak to margins on Sidebery
- Fix weird bug with Sidebar to expanding properly

artifacts