Change default font to JetBrainsMono Nerd Font

Caskaydia Mono doesn't look quite right in Ghostty

bin/omarchy-theme-set-obsidian

@@ -391,7 +391,7 @@ extract_theme_data() {
   readarray -t color_slots < <(fill_color_slots "${unique_colors[@]}" | tr ' ' '\n')
 
   # Extract fonts
-  local monospace_font="CaskaydiaMono Nerd Font"
+  local monospace_font="JetBrainsMono Nerd Font"
   local ui_font="Liberation Sans"
 
   if [ -f "$CURRENT_THEME_DIR/alacritty.toml" ]; then