Normalize k0s node names before maintenance

[kv1sidisi]

• Normalize node names to lowercase before kubectl maintenance and readiness checks.
• Catch case-only hostname duplicates earlier and keep reset flows aligned with the same node identity.

[Copilot]

Pull request overview

This PR standardizes how k0sctl derives the Kubernetes node name from a host by normalizing hostnames to lowercase before running kubectl-based readiness checks and node maintenance operations, and by validating hostname uniqueness using the normalized node identity.

Changes:

• Introduces Host.KubernetesNodeName() (lowercased hostname) and switches kubectl node operations (drain/cordon/uncordon/delete/taints) to use it.
• Updates node readiness checks and reset flows to reference the normalized node name.
• Updates host validation to detect case-only hostname duplicates earlier; adds a unit test for KubernetesNodeName().

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
pkg/node/statusfunc.go	Uses normalized node name for kubectl get node readiness checks and related error messages.
pkg/apis/k0sctl.k0sproject.io/v1beta1/cluster/host.go	Adds KubernetesNodeName() and applies it across kubectl node maintenance helpers.
pkg/apis/k0sctl.k0sproject.io/v1beta1/cluster/host_test.go	Adds unit test ensuring node name normalization behavior.
phase/validate_hosts.go	Validates hostname uniqueness using the normalized Kubernetes node name.
phase/reset_workers.go	Uses normalized node name when draining/deleting worker nodes during reset.
phase/reset_controllers.go	Uses normalized node name when draining/deleting controller-worker nodes during reset.
phase/gather_k0s_facts.go	Logs worker-join readiness checks using the normalized node name.
phase/gather_facts.go	Normalizes configured hostname override to lowercase when setting host metadata.

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[kke]

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