[Feature] Linux Kernel 6.12 and netkit with Cilium

**Is your feature request related to a problem? Please describe.**
No, just a nice to have.

**Describe the solution you'd like**
We are interested in trying out [netkit with Cilium](https://isovalent.com/blog/post/cilium-netkit-a-new-container-networking-paradigm-for-the-ai-era/).
However the complicating factor is that netkit was only added to the Linux kernel in 6.7. Apparently Azure Linux defaults to 6.6 but has support for [6.12](https://github.com/microsoft/azurelinux/releases/tag/3.0.20250910-3.0).

Wondering if it would be possible to upgrade the Linux kernel to 6.12 in AKS and enable netkit with Cilium?

****Let me know if this needs to be split into 2 different feature requests.***

**Describe alternatives you've considered**

**Additional context**

Start by reviewing AKS support for Azure Linux kernel 6.12 and the linked Azure Linux 3.0.20250910 release, then verify the Cilium netkit requirements described in the linked blog. Done means AKS can use kernel 6.12 and netkit with Cilium, with the required support and enablement clearly documented.

Written by the indexing model from the issue text.