[Feature] Roadmap for Gateway API v1.6.x and TCPRoute support

## Is your feature request related to a problem? Please describe.

ALB Controller v1.11.3 currently supports Gateway API v1.5.1. We have a concrete use case that requires routing non-HTTP TCP traffic through the Gateway API.

`TCPRoute` became generally available in the Standard Channel with Gateway API v1.6.0. However, it cannot currently be used with the ALB Controller. This prevents us from managing both Layer 4 TCP traffic and existing Layer 7 traffic through a consistent Gateway API implementation.

Is support for Gateway API v1.6.x, including `TCPRoute`, currently on the roadmap for the ALB Controller? If so, could you share the planned target release or an approximate timeframe?

## Describe the solution you'd like

We would like the ALB Controller and Application Gateway for Containers to support Gateway API v1.6.x, particularly:

* Gateway listeners using the `TCP` protocol
* `TCPRoute` resources
* Routing TCP connections to Kubernetes Services referenced through `backendRefs`

Ideally, the supported features and any limitations would also be documented in the ALB Controller release notes and Gateway API compatibility documentation.

## Describe alternatives you've considered

As alternatives, we considered exposing the workload through a Kubernetes Service of type `LoadBalancer` or operating an additional Gateway API controller with `TCPRoute` support.

Both approaches would introduce a separate traffic-management path and additional operational overhead. They would also prevent us from consistently managing our ingress configuration through the existing ALB Controller and Application Gateway for Containers setup.

## Additional context

* [ALB Controller release notes](https://learn.microsoft.com/en-us/azure/application-gateway/for-containers/alb-controller-release-notes)
* [Gateway API TCPRoute documentation](https://gateway-api.sigs.k8s.io/reference/api-types/tcproute/)