refactor: nixify / clean remaining dots scripts

home/modules/waybar/scripts/sb-tasks

@@ -0,0 +1,5 @@
+num_done="$(task end.after:today status:completed count)"
+num_pending="$(($(task count status:pending) + num_done))"
+num_waiting="$(task count status:waiting)"
+
+echo "Tasks: $num_done/$num_pending+$num_waiting"