feat: add repeatable kubeadm rebuild and reset scripts

nixos/kubeadm/scripts/reset-cluster-nodes.sh

@@ -0,0 +1,37 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+INVENTORY_FILE="${1:-$SCRIPT_DIR/inventory.env}"
+
+if [ ! -f "$INVENTORY_FILE" ]; then
+  echo "Missing inventory file: $INVENTORY_FILE"
+  echo "Copy $SCRIPT_DIR/inventory.example.env to $SCRIPT_DIR/inventory.env and edit IPs."
+  exit 1
+fi
+
+# shellcheck disable=SC1090
+source "$INVENTORY_FILE"
+
+SSH_USER="${SSH_USER:-micqdf}"
+SSH_OPTS="${SSH_OPTS:- -o BatchMode=yes -o StrictHostKeyChecking=accept-new }"
+
+required=(CP_1 CP_2 CP_3 WK_1 WK_2 WK_3)
+for key in "${required[@]}"; do
+  if [ -z "${!key:-}" ]; then
+    echo "Missing required inventory variable: $key"
+    exit 1
+  fi
+done
+
+reset_node() {
+  local node_ip="$1"
+  echo "==> Resetting $node_ip"
+  ssh $SSH_OPTS "$SSH_USER@$node_ip" "sudo kubeadm reset -f && sudo systemctl stop kubelet && sudo rm -rf /etc/kubernetes /var/lib/etcd /var/lib/cni /etc/cni/net.d"
+}
+
+for key in CP_1 CP_2 CP_3 WK_1 WK_2 WK_3; do
+  reset_node "${!key}"
+done
+
+echo "Cluster components reset on all listed nodes."