v2.0.0 - Major UI Refresh

New Features:
- Complete visual redesign with modern dark theme
- New SVG icons for all toolbar buttons (clean, scalable)
- 6 color themes: Dark, Ocean, Forest, Sunset, Midnight, and Light
- Improved sidebar navigator with better folder expand/collapse
- Refined folder and bookmark icons with proper emoji rendering
- Updated edit mode with clearer delete indicators
- Better responsive layout for smaller screens

Fixes:
- Fixed folder icon displaying incorrectly (was showing garbled text)
- Fixed edit mode delete button showing wrong character
- Improved overall visual consistency and spacing
- Smoother animations and transitions

All functionality remains the same — just looks much better!