fix: preserve kube-vip mount path and only swap hostPath to super-admin

The previous replacement changed both mountPath and hostPath, causing kube-vip to lose its expected in-container kubeconfig path and exit. Keep mountPath at /etc/kubernetes/admin.conf, swap only hostPath during bootstrap, and enable kube-vip debug log level.

nixos/kubeadm/modules/k8s-common.nix

@@ -184,6 +184,7 @@ in
       echo "==> Creating kube-vip static pod manifest"
       ctr image pull "${kubeVipImage}"
       ctr run --rm --net-host "${kubeVipImage}" kube-vip-manifest /kube-vip manifest pod \
+        --log -4 \
         --interface "$iface" \
         --address "$vip" \
         --controlplane \
@@ -192,7 +193,9 @@ in
 
       # kube-vip bootstrap workaround for Kubernetes >=1.29.
       # During early kubeadm phases, super-admin.conf is available before admin.conf is fully usable.
-      sed -i 's#/etc/kubernetes/admin.conf#/etc/kubernetes/super-admin.conf#g' /etc/kubernetes/manifests/kube-vip.yaml || true
+      sed -i 's#path: /etc/kubernetes/admin.conf#path: /etc/kubernetes/super-admin.conf#' /etc/kubernetes/manifests/kube-vip.yaml || true
+      echo "==> kube-vip manifest kubeconfig mount"
+      grep -E 'mountPath:|path:' /etc/kubernetes/manifests/kube-vip.yaml | grep -E 'kubernetes/(admin|super-admin)\.conf' || true
 
       env -i PATH=/run/current-system/sw/bin:/usr/bin:/bin kubeadm init \
         --config /tmp/kubeadm/init-config.yaml \
@@ -250,7 +253,7 @@ in
       done
 
       # Switch kube-vip to normal admin.conf after bootstrap finishes.
-      sed -i 's#/etc/kubernetes/super-admin.conf#/etc/kubernetes/admin.conf#g' /etc/kubernetes/manifests/kube-vip.yaml || true
+      sed -i 's#path: /etc/kubernetes/super-admin.conf#path: /etc/kubernetes/admin.conf#' /etc/kubernetes/manifests/kube-vip.yaml || true
 
       mkdir -p /root/.kube
       cp /etc/kubernetes/admin.conf /root/.kube/config
@@ -293,6 +296,7 @@ in
       mkdir -p /etc/kubernetes/manifests
       ctr image pull "${kubeVipImage}"
       ctr run --rm --net-host "${kubeVipImage}" kube-vip /kube-vip manifest pod \
+        --log -4 \
         --interface "$iface" \
         --address "$vip" \
         --controlplane \