- Add EDITOR and VISUAL environment variables to fish shell init
- Add system-level EDITOR and VISUAL variables for macOS and WSL
- Ensures nvim is used as default editor for git, system tools, and applications
- Maintains existing neovim defaultEditor configuration
- Create unified theme.sh script that works on both WSL and macOS
- Update fish alias to use new unified script instead of WSL-specific one
- Maintain backward compatibility with existing theme command
- Update documentation to reflect unified approach
- Script automatically detects platform and calls appropriate functionality
