[codex] Refine Python SDK user-facing docs (#22941)

## Summary
- Remove maintainer and release-process wording from the Python SDK
README and docs.
- Rewrite SDK-facing comments/docstrings so they read as standalone
product documentation.
- Add a real app-server integration smoke that follows the public
quickstart-style `Codex() -> thread_start() -> run()` path.

## Integration coverage
- Add `test_real_quickstart_style_flow_smoke` in the real app-server
integration suite.

## Validation
- Local tests were not run per repo guidance. CI should validate this
branch once the PR is online.

sdk/python/docs/faq.md

@@ -59,29 +59,6 @@ Common causes:
 - local auth/session is missing
 - incompatible/old app-server
 
-Maintainers stage releases by building the SDK once and the runtime once per
-platform with the same pinned runtime version. Publish `openai-codex-cli-bin`
-as platform wheels only; do not publish an sdist:
-
-```bash
-cd sdk/python
-python scripts/update_sdk_artifacts.py generate-types
-python scripts/update_sdk_artifacts.py \
-  stage-sdk \
-  /tmp/codex-python-release/openai-codex \
-  --codex-version <codex-release-tag-or-pep440-version>
-python scripts/update_sdk_artifacts.py \
-  stage-runtime \
-  /tmp/codex-python-release/openai-codex-cli-bin \
-  /path/to/codex \
-  --codex-version <codex-release-tag-or-pep440-version>
-```
-
-If you are packaging a binary for a different target than the Python build
-host, pass `--platform-tag ...` to `stage-runtime`. The intended one-off matrix
-is `macosx_11_0_arm64`, `macosx_10_9_x86_64`, `musllinux_1_1_aarch64`,
-`musllinux_1_1_x86_64`, `win_arm64`, and `win_amd64`.
-
 ## Why does a turn "hang"?
 
 A turn is complete only when `turn/completed` arrives for that turn ID.