Handle Responses streams with missing terminal output

[JuzhengSi]

Summary

• recover Responses streams when the terminal event omits response.output but earlier output_item.done/text deltas were already received
• share the recovery path between the main Codex stream runtime and the auxiliary Responses adapter
• add regression coverage for malformed terminal streaming events

Why

Some OpenAI-compatible Responses endpoints emit valid incremental SSE events, then send a response.completed payload without an output field. OpenAI SDK parsing raises TypeError: 'NoneType' object is not iterable while iterating the stream, before Hermes can use the already streamed output. This makes the error look like a non-retryable client failure even though the assistant output was already available.

Tests

• ./venv/bin/python -m py_compile agent/codex_runtime.py agent/auxiliary_client.py tests/agent/test_codex_stream_recovery.py
• ./venv/bin/python -m pytest tests/agent/test_codex_stream_recovery.py tests/agent/test_codex_ttfb_watchdog.py tests/agent/test_auxiliary_client.py -q

[alt-glitch]

Duplicate of #32884. Same Codex null output recovery. Root cause: #11179.

[teknium1]

Closing as duplicate — the Codex null-output fix has been merged via #32963 (cherry-picked from @carltonawong's PR #32890). Thanks for the help during the outage. Closes #11179.