The Codex CLI can return "no rollout found for thread id ..." when
resuming a heartbeat thread whose rollout has been garbage-collected.
Extend isCodexUnknownSessionError() to match this wording so the
existing single-retry path in execute.ts activates correctly.
Add parse.test.ts covering the new pattern, existing stale-session
wordings, parseCodexJsonl, and a negative case.
Co-Authored-By: Paperclip <noreply@paperclip.ing>
Dotta