feat: add Ghostty terminal support (#225)

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.

extras/ghostty/vimbones

@@ -0,0 +1,37 @@
+# This file is auto-generated by shipwright.nvim
+# Ghostty color configuration
+# See: https://ghostty.org/docs/config/reference
+# Basic colors
+foreground = "#353535"
+background = "#F0F0CA"
+# Selection colors
+selection-foreground = "#353535"
+selection-background = "#D7D7D7"
+# Cursor colors
+cursor-color = "#353535"
+cursor-text = "#F0F0CA"
+# The basic 16 colors
+# black
+palette = 0=#F0F0CA
+palette = 8=#C6C6A3
+# red
+palette = 1=#A8334C
+palette = 9=#94253E
+# green
+palette = 2=#4F6C31
+palette = 10=#3F5A22
+# yellow
+palette = 3=#944927
+palette = 11=#803D1C
+# blue
+palette = 4=#286486
+palette = 12=#1D5573
+# magenta
+palette = 5=#88507D
+palette = 13=#7B3B70
+# cyan
+palette = 6=#3B8992
+palette = 14=#2B747C
+# white
+palette = 7=#353535
+palette = 15=#5C5C5C