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.

lua/zenbones/shipwright/runners/ghostty.lua

@@ -0,0 +1,68 @@
+local helpers = require "shipwright.transform.helpers"
+
+local base_template = [[
+# Ghostty color configuration
+# See: https://ghostty.org/docs/config/reference
+
+# Basic colors
+foreground = "$fg"
+background = "$bg"
+
+# Selection colors
+selection-foreground = "$selection_fg"
+selection-background = "$selection_bg"
+
+# Cursor colors
+cursor-color = "$cursor_bg"
+cursor-text = "$cursor_fg"
+
+# The basic 16 colors
+# black
+palette = 0=$black
+palette = 8=$bright_black
+
+# red
+palette = 1=$red
+palette = 9=$bright_red
+
+# green
+palette = 2=$green
+palette = 10=$bright_green
+
+# yellow
+palette = 3=$yellow
+palette = 11=$bright_yellow
+
+# blue
+palette = 4=$blue
+palette = 12=$bright_blue
+
+# magenta
+palette = 5=$magenta
+palette = 13=$bright_magenta
+
+# cyan
+palette = 6=$cyan
+palette = 14=$bright_cyan
+
+# white
+palette = 7=$white
+palette = 15=$bright_white]]
+
+local function ghostty_conf(colors)
+	local text = helpers.apply_template(base_template, colors)
+
+	return helpers.split_newlines(text)
+end
+
+---@diagnostic disable: undefined-global
+-- selene: allow(undefined_variable)
+run(
+	{ specs, p, term },
+	transform.colorscheme_to_term_colors,
+	ghostty_conf,
+	{ prepend, "# This file is auto-generated by shipwright.nvim" },
+	{ overwrite, string.format("extras/ghostty/%s", name) }
+)
+-- selene: deny(undefined_variable)
+---@diagnostic enable: undefined-global