added manual kubernetes clean up script

scripts/cleanup-manual-vm.sh

@@ -0,0 +1,16 @@
+#!/usr/bin/env bash
+# Tears down stage 2's throwaway k3s-manual VM (docs/02-k3s.md).
+# See docs/04-tofu.md, "Tearing down the manual VM" for what each step does
+# and why nothing else needs cleaning up.
+set -euo pipefail
+
+read -p "This will destroy the k3s-manual VM and its disks. Continue? [y/N] " confirm
+[[ "$confirm" =~ ^[Yy]$ ]] || exit 0
+
+virsh -c qemu:///system destroy k3s-manual 2>/dev/null || true
+virsh -c qemu:///system undefine k3s-manual --remove-all-storage 2>/dev/null || true
+virsh -c qemu:///system vol-delete --pool default k3s-manual-base.qcow2 2>/dev/null || true
+rm -f ~/.kube/config-manual
+rm -rf ~/vms
+
+echo "k3s-manual cleaned up."