Chore description

Since Kubeflow Summit NA finished, we need to update the home page header to the upcoming event in KubeCon Europe 2026.
Find event's name and event's info here:
https://events.linuxfoundation.org/kubecon-cloudnativecon-europe/co-located-events/cloud-native-ai-kubeflow-day/

Labels
/area website
/area community

Component/Kubeflow Version:

Labels

/area website
/area community

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