AgentGateway Integration Docs

[npolshakova]

Adds Docs to highlight Agent Gateway integration functionality:

• Initial integration PR: Add AgentGateway Support #11150
• EP: [EP] Agent Gateway Integration #11152

[npolshakova]

@Nadine2016 can we get someone from Docs to pick this up? The initial steps are documented in #11151

[christian-posta]

And I have the steps validated here:

https://github.com/christian-posta/scripted-solo-demos/blob/master/agentgateway/kubernetes/README.md

[artberger]

Related user question in Slack: https://cloud-native.slack.com/archives/C080D3PJMS4/p1748955699630849

[Nadine2016]

@npolshakova we will pick this up and will try to get it published this week or early next week

[timflannagan]

Can this be closed out? @npolshakova

[artberger]

Here is the agentgateway section in the docs: https://kgateway.dev/docs/latest/agentgateway/

Going to close this for now, but feel free to reopen if needed!