add ghostty config and theme

configs/ghostty_g/themes/CGA

@@ -0,0 +1,21 @@
+palette = 0=#000000
+palette = 1=#aa0000
+palette = 2=#00aa00
+palette = 3=#aa5500
+palette = 4=#0000aa
+palette = 5=#aa00aa
+palette = 6=#00aaaa
+palette = 7=#aaaaaa
+palette = 8=#555555
+palette = 9=#ff5555
+palette = 10=#55ff55
+palette = 11=#ffff55
+palette = 12=#5555ff
+palette = 13=#ff55ff
+palette = 14=#55ffff
+palette = 15=#ffffff
+background = 000000
+foreground = aaaaaa
+cursor-color = b8b8b8
+selection-background = c1deff
+selection-foreground = 000000