fix(agents): accept Codex turns after reconnect

[antoinegg1]

Summary

• Treat an intermediate Codex app-server error as superseded when the same turn later completes successfully.
• Preserve immediate failure behavior for terminal failed or interrupted turns.
• Cover a Reconnecting... 1/5 event followed by successful completion.

Validation

• uv run pre-commit run --all-files
• uv run pytest tests/agents/test_appservers.py -q: 45 passed
• uv run pytest --ignore=tests/coganchor: 1469 passed, 36 skipped

The complete suite was also attempted. Coganchor tests cannot run in this container because pidfd_getfd returns EPERM without CAP_SYS_PTRACE; before interruption, 500 tests passed and 65 skipped, with failures limited to tests/coganchor.