fix: recover codex streams with missing final output

[sgtworkman]

Summary

• Recover Codex Responses streams when the OpenAI SDK crashes parsing the final response after valid streamed output items/text.
• Apply the same recovery to the auxiliary Codex adapter used by title generation and other side tasks.
• Add regressions for main Codex stream and auxiliary title-generation stream recovery paths.

Validation

• scripts/run_tests.sh tests/agent/test_auxiliary_client.py tests/run_agent/test_run_agent_codex_responses.py — 245 passed
• python -m pytest tests/agent/test_auxiliary_client.py -q — 178 passed, 1 warning
• hermes -z "you good" --provider openai-codex -m gpt-5.5 — passed and returned a normal response
• git diff --check — passed

Safety

• Source-only change.
• No merge.
• No deploy.
• No DNS/indexing/production mutation.

[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.