ghostty: speedup start

home/progs/ghostty.nix

@@ -23,6 +23,11 @@
 
       # cursor
       cursor-style = "underline";
+
+      # keep one daemon alive so subsequent launches (e.g. niri Mod+T) are
+      # instant instead of paying GTK + wgpu init each time. relies on the
+      # dbus-activated systemd user service that the HM module wires up.
+      gtk-single-instance = true;
     };
   };