agent-platform release v4.64.0

Changed

• The agentgateway line at 2.1.0 for the controller and the data planes (agentgateway.controller.image, agentgateway.proxy.image; giantswarm/agent-platform#630). 2.1.0 is the line on upstream main @ 08f4563b (the 2026-09-22 re-pin, 229 commits past v1.5.0: the substrate egress credential injection the Substrate line’s pin was chosen for, upstream’s 413 with the limit for an oversized MCP request) plus the line’s carried patch that names an oversized MCP upstream answer’s size and the limit — upstream response body of N bytes exceeds the maximum buffer size of L bytes instead of body exceeded buffer limit — so a tool answer above gateway.http.maxBufferSize is refused with both numbers. Substrate’s egress gateway (substrate.images.agentgateway) stays on 2.0.0: it moves with the Substrate release whose egress configuration is written for it (make verify-substrate-images).