Mark KubeVirt live migration as tech preview in release notes

The KubeVirt networking page marks live migration support as a tech
preview feature. Match that by adding the "(tech preview)" heading
suffix (consistent with other tech-preview items in this section) and
noting that live migration is tech preview and currently requires BGP
networking without overlay.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: ctauchen

calico-enterprise_versioned_docs/version-3.23-2/release-notes/index.mdx

@@ -67,12 +67,14 @@ This is the first phase of phasing out the aggregated API server: in a future re
 
 For more information, see [Enable native v3 CRDs](../operations/native-v3-crds.mdx) and [Migrate from API server to native CRDs](../operations/crd-migration.mdx).
 
-### Live migration for KubeVirt VMs
+### Live migration for KubeVirt VMs (tech preview)
 
 $[prodname] now provides first-class networking for KubeVirt virtual machines, including persistent IP addresses and BGP-aware live migration.
 A VM keeps the same IP address across reboots, pod evictions, and live migrations, and $[prodname] uses route priority to steer traffic to the new host as a running VM migrates between nodes without breaking established connections.
 In single-rack iBGP deployments this works automatically; in multi-rack or eBGP topologies, you configure `BGPFilter` resources to propagate route priority across AS boundaries.
 
+Live migration support is a tech preview feature and may change significantly before it becomes GA. It currently requires BGP networking without overlay.
+
 For more information, see [Calico Enterprise networking for KubeVirt](../networking/kubevirt/kubevirt-networking.mdx) and [BGP routing for KubeVirt live migration](../networking/kubevirt/live-migration-bgp.mdx).
 
 {/* End 3.23.0-2.0 features */}