code: func normalizedBuildVersion(version string) string {
  	if kubeReleaseRegex.MatchString(version) {
  		if strings.HasPrefix(version, "v") {
  			return version
  		}
  		return "v" + version
  	}
  	return ""
  }
docs: // Internal helper: returns normalized build version (with "v" prefix if needed)
  // If input doesn't match known version pattern, returns empty string.