- Added comprehensive dark mode styling to all pages:
* Dashboard (workflow guide, secondary text, log items)
* Admin panel with user management system
* Content/playlist management page
* Upload media page
* Add player page
- Implemented user management system:
* Create/edit/delete users
* Two role types (user/admin)
* Reset password functionality
* Role-based permissions
- Replaced group assignment with playlist assignment:
* Players now directly assigned to playlists
* Updated add player form and backend
* Removed group selection from player creation
- Fixed bugs:
* Updated instance_path configuration for SQLite
* Fixed import path in app factory
* Updated dependencies (Pillow 11.0.0, removed gevent)
- Added start.sh script for easy development server launch
