shortcodes: fix version lag calculation for mixed CalVer/semver

Comparing a semver minor (e.g. 10 from v1.10.0) against a CalVer month
(e.g. 3 from 26.03) produced a nonsensical negative lag. Now detects
scheme per release: CalVer uses month-based lag, semver uses minor-based
lag, and mixed schemes show a "legacy semver release" message instead of
a meaningless number.

Assisted-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Signed-off-by: Christian Heusel <christian@heusel.eu>

Author: christian-heusel

layouts/shortcodes/kf-version-notice.html

@@ -40,8 +40,25 @@
 {{- $this_release_date := $this_release.publish_date | time.AsTime }}
 {{- $this_release_date_string := $this_release_date | time.Format ":date_long" }}
 
-{{- $this_version_lag := sub $latest_release_minor $this_release_minor }}
-{{- $popup_content_prefix := printf "Kubeflow %s was initially released on <strong>%s</strong> and is <strong>%d</strong> minor versions behind the latest release." $version_full $this_release_date_string $this_version_lag }}
+{{- $latest_is_calver := not (strings.HasPrefix $latest_release.tag "v") }}
+{{- $this_is_calver := not (strings.HasPrefix $this_release.tag "v") }}
+{{- $this_version_lag := 0 }}
+{{- if and $latest_is_calver $this_is_calver }}
+  {{- /* Both CalVer: compute lag in months */}}
+  {{- $this_version_lag = sub (add (mul $latest_release_major 12) $latest_release_minor) (add (mul $this_release_major 12) $this_release_minor) }}
+{{- else if and (not $latest_is_calver) (not $this_is_calver) }}
+  {{- /* Both semver: compare minor versions */}}
+  {{- $this_version_lag = sub $latest_release_minor $this_release_minor }}
+{{- else }}
+  {{- /* Mixed schemes: this is a legacy semver release, latest is CalVer */}}
+  {{- $this_version_lag = -1 }}
+{{- end }}
+{{- $popup_content_prefix := "" }}
+{{- if lt $this_version_lag 0 }}
+  {{- $popup_content_prefix = printf "Kubeflow %s was initially released on <strong>%s</strong> and is 1 version behind the latest release. This is a legacy semver release; the project has since moved to CalVer versioning." $version_full $this_release_date_string }}
+{{- else }}
+  {{- $popup_content_prefix = printf "Kubeflow %s was initially released on <strong>%s</strong> and is <strong>%d</strong> minor versions behind the latest release." $version_full $this_release_date_string $this_version_lag }}
+{{- end }}
 {{- $popup_content_suffix := "Distributions are supported by their maintainers. Contact the provider for information on support and updates." }}
 
 {{- $button_style := "" }}