sloproxy

feat(codex): support orphan delegation compatibility via orphan-delegation-compatibility master

- Add `codex.orphan-delegation-compatibility` configuration option and mirror it to SDK configuration. - Convert orphan Codex delegation outputs into standard user messages for requests with `X-Openai-Subagent: collab_spawn`. - Integrate orphan delegation rewriting into OpenAI responses request handling pipeline. Closes: #5401