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/nordbones

@@ -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 = "#EBEEF3"
+background = "#2F3541"
+# Selection colors
+selection-foreground = "#EBEEF3"
+selection-background = "#545F70"
+# Cursor colors
+cursor-color = "#EEF1F5"
+cursor-text = "#2F3541"
+# The basic 16 colors
+# black
+palette = 0=#2F3541
+palette = 8=#475063
+# red
+palette = 1=#C1616A
+palette = 9=#D6787F
+# green
+palette = 2=#A4BE8D
+palette = 10=#A8CC86
+# yellow
+palette = 3=#CF866F
+palette = 11=#E09680
+# blue
+palette = 4=#8FBCBA
+palette = 12=#89CAC8
+# magenta
+palette = 5=#B38DAC
+palette = 13=#CF97C5
+# cyan
+palette = 6=#87BFCE
+palette = 14=#82CCE0
+# white
+palette = 7=#EBEEF3
+palette = 15=#A5B4CD