Version comparison crash in validate_inventory when kube_version has 'v' prefix

Bug Report

Environment

• Kubespray: master branch (cloned 2026-04-11)
• Ansible: 11.13.0 (ansible-core 2.18.15)
• OS: Ubuntu 24.04 (nodes), macOS (controller)
• Python: 3.14

Description

When running cluster.yml with a kube_version that uses a v prefix (e.g. v1.31.4) and that version is older than the minimum supported, the version comparison in validate_inventory crashes with a Python type error instead of showing the intended human-readable error message.

Error

TASK [validate_inventory : Stop if unsupported version of Kubernetes]
fatal: [k8s-control-1]: FAILED! => {
    "msg": "The conditional check 'kube_version is version(kube_version_min_required, '>=')' failed.
    The error was: Version comparison failed: '<' not supported between instances of 'str' and 'int'"
}

Root Cause

In roles/kubespray_defaults/defaults/main/main.yml:

kube_version_min_required: "{{ (kubelet_checksums['amd64'] | dict2items)[-1].key }}"

This produces a bare version string like 1.33.4 (no v prefix). When compared against a user-supplied kube_version: v1.31.4 (with v prefix), the Jinja2 version filter fails with a type error instead of performing a proper semantic version comparison.

Expected Behavior

The assertion should either:

1. Strip the v prefix before comparison, or
2. Produce the intended error message: "The current release of Kubespray only support newer version of Kubernetes than X - You are trying to apply Y"

Steps to Reproduce

1. Clone Kubespray master
2. Set kube_version: v1.31.4 in group vars (any version older than the minimum and with v prefix)
3. Run ansible-playbook cluster.yml

Context

I'm testing this in my home lab environment and ran into this while upgrading from Kubespray v2.26.0 to master.