fix(codex): suppress commentary phase leakage

[yolopsx]

Summary

• Suppress Codex Responses commentary / analysis phase text from visible assistant content.
• Preserve Codex message items internally for replay/state continuity.
• Update streaming expectations so raw output_text.delta is cached, not emitted to platform callbacks before phase-aware normalization.

Why

commentary and analysis can contain internal planning. They should not appear in Telegram/CLI/UI output unless a final-answer phase is present.

Test Plan

• venv/bin/python -m pytest tests/run_agent/test_run_agent_codex_responses.py tests/run_agent/test_streaming.py::TestCodexStreamCallbacks -q
• Result: 67 passed in 18.80s

Notes

Opened as draft because this is a visibility/privacy hardening change and maintainers may want to review provider replay semantics carefully.

[alt-glitch]

Possible duplicate of open #25268 and #21568, both targeting the same codex commentary phase leakage (issue #24933). Reviewers: please compare approaches and consolidate.