- preserve sandbox child environment variables from shared launch requests
- dispatch codex-exec-server through codex-arg0 so helper arg0 is executable
- send sandbox preference to remote servers and report the server-selected sandbox
Co-authored-by: Codex <noreply@openai.com>
Stacked PR 2/3, based on the stub PR.
Adds the exec RPC implementation and process/event flow in exec-server
only.
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Co-authored-by: Codex <noreply@openai.com>