Add shipwright runner for Ghostty terminal emulator with example themes.
- Add ghostty.lua runner with Ghostty-specific color format
- Update init.lua to include ghostty in runner_files
- Add zenbones_dark and zenbones_light example themes
Ghostty uses a similar format to Kitty but with `=` separators and
`palette = N=COLOR` syntax for the 16 ANSI colors.
Tested and working with Ghostty terminal.
3da02e553a