Dashboard AKS navigation warning

Motivation

The top navigation showed the AKS readiness warning dot and tooltip on New Search, even though the warning describes cluster health that belongs to the Dashboard monitoring surface.

User-facing change

When no workload cluster is ready, the orange warning dot and hover tooltip now appear on Dashboard. New Search remains a plain navigation entry instead of carrying the cluster-health warning.

API/IaC diff summary

No API or IaC changes. This is a React navigation presentation change in web/src/components/Layout.tsx.

Validation evidence

cd web && npm run build passed on 2026-05-26.