feat: Implement custom scrollbar styling using --persian-plum-900

[davesalvador]

• Applied custom scrollbar styles globally for better UI consistency.
• Styled the scrollbar with --persian-plum-900 (#773535) for the thumb and --persian-plum-50 (#F7F3F3) for the track.
• Adjusted hover states with --persian-plum-800 for enhanced visual feedback.
• Ensured cross-browser compatibility with WebKit and Firefox scrollbar styling.