agent-platform release v3.23.0

The agentgateway data plane runs the Giant Swarm line of agentgateway: the connectivity chart’s agentgateway.proxy.image.tag (rendered into AgentgatewayParameters) is v1.5.1-gs.1 — upstream v1.5.0 rebuilt, scanned and signed in giantswarm/agentgateway-upstream (its FORK.md; tracking giantswarm/giantswarm#37758) and mirrored into gsoci by the retagger — the same release the giantswarm/agentgateway packaging chart pins for the controller, so a fix the platform needs in agentgateway can be carried on the line and reaches every installation as the next -gs.N release. Every installation with the agentgateway component on rolls its data-plane pods once to an image built from the same source as before; nothing else in the render changes.