Controller improvements for experimental AIGateway

## Problem Statement

The current implementation of `AIGateway` is marked as `experimental`, and is fairly "bare bones" at the moment. There's some basic maintenance items we need to take care of on the controller implementation.

## Acceptance Criteria

- [ ] `GenerateName` should be used for owned resources created by the controller
- [ ] Updates to owned and related resources should trigger reconcilation (e.g. watchers for `GatewayClass`, `Gateway`, `KongPlugins`, e.t.c.) and integration tests should be added to verify these relationships
- [ ] Status handling needs to be added, including implementing the `Endpoints` part of the status. As a user, I should be able to run `kubectl get aigateways` and determine a) if the `AIGateway` is ready to be used b) what `Endpoints` I can reach the `AIGateway` at to use it.

Feel free to break these items out into individual issues as needed for smaller iterations.

Start by locating the experimental AIGateway controller implementation and its current integration-test entry points. Trace owned-resource creation and reconciliation relationships first, then define coverage for GenerateName, related-resource watchers, and status Endpoints; done means kubectl get aigateways reports readiness and reachable endpoints.

Written by the indexing model from the issue text.