add ghostty config and theme

configs/ghostty_g/themes/OneHalfDark

@@ -0,0 +1,21 @@
+palette = 0=#282c34
+palette = 1=#e06c75
+palette = 2=#98c379
+palette = 3=#e5c07b
+palette = 4=#61afef
+palette = 5=#c678dd
+palette = 6=#56b6c2
+palette = 7=#dcdfe4
+palette = 8=#282c34
+palette = 9=#e06c75
+palette = 10=#98c379
+palette = 11=#e5c07b
+palette = 12=#61afef
+palette = 13=#c678dd
+palette = 14=#56b6c2
+palette = 15=#dcdfe4
+background = 282c34
+foreground = dcdfe4
+cursor-color = a3b3cc
+selection-background = 474e5d
+selection-foreground = dcdfe4