added get-focused-monitor helper script

home/common/optional/desktop/dwm/scripts/get-focused-monitor.nix

@@ -0,0 +1,25 @@
+{ pkgs, ... }:
+{
+  home.packages = with pkgs; [
+    (writeShellScriptBin "get-focused-monitor" ''
+      # get the current cursor location into X and Y variables
+      eval $(xdotool getmouselocation --shell)
+      
+      # compare mouse location to monitor coordinates
+      while IFS= read -r line; do
+        if [[ $line =~ " connected" ]]; then
+          display=$(echo "$line" | awk '{print $1}')
+          coords=$(echo "$line" | grep -oP "\d+x\d+" | tr 'x+' ' ')
+      
+          read width height x_offset y_offset <<< $coords
+      
+          if (( X >= x_offset && X <= width + x_offset )) && (( Y >= y_offset && Y <= height + y_offset )); then
+            echo "$display"
+            break
+          fi
+        fi
+      done < <(xrandr)
+      
+    '')
+  ];
+}