OpenAI Responses adapter

Developed by Dahl together with Gonka External TestLab.

Where it lives: the broker OpenAI HTTP proxy, same process as POST /v1/chat/completions, before the inference gateway.

CompatCanary --profile modern is how the gap usually shows (405 on /v1/responses). Codex CLI and Agents SDK (client.responses.create()) hard-call this path. Chat Completions stays for Cursor / chat-mode Cline / most SDKs.