fix: ensure kubelet is enabled for kubeadm init node registration

Enable kubelet before kubeadm init and stop forcing kubelet out of wantedBy so kubeadm can reliably register the node during upload-config/kubelet. Also clear stale kubelet config files during remote prep to avoid restart-loop leftovers.

nixos/kubeadm/modules/k8s-common.nix

@@ -138,6 +138,7 @@ in
 
       systemctl daemon-reload
       systemctl unmask kubelet || true
+      systemctl enable kubelet || true
 
       echo "==> Ensuring containerd is running"
       systemctl start containerd || true
@@ -340,7 +341,6 @@ in
 
   systemd.services.kubelet = {
     description = "Kubernetes Kubelet";
-    wantedBy = lib.mkForce [];
     wants = [ "network-online.target" ];
     after = [ "containerd.service" "network-online.target" ];
     serviceConfig = {