Remove CODEX_PYTHON_RUNTIME_VERSION from the repo bootstrap path and always provision the checked-in pinned codex-cli-bin runtime version for examples, notebook, and real integration coverage.
This keeps repo-source Python execution aligned with one binary contract, rewires the real integration harness and notebook bootstrap to use the pinned runtime directly, and updates the docs to describe automatic pinned-runtime provisioning instead of env-driven overrides.
Validation:
- RUN_REAL_CODEX_TESTS=1 python3 -m pytest sdk/python/tests -rs
- RUN_REAL_CODEX_TESTS=1 python3 -m pytest sdk/python/tests/test_real_app_server_integration.py -rs
Co-authored-by: Codex <noreply@openai.com>
## TL;DR
Bring the Python app-server SDK from `main-with-prs-13953-and-14232`
onto current `main` as a standalone SDK-only PR.
- adds the new `sdk/python` and `sdk/python-runtime` package trees
- keeps the scope to the SDK payload only, without the unrelated
branch-history or workflow changes from the source branch
- regenerates `sdk/python/src/codex_app_server/generated/v2_all.py`
against current `main` schema so the extracted SDK matches today's
protocol definitions
## Validation
- `PYTHONPATH=sdk/python/src python3 -m pytest sdk/python/tests`
Co-authored-by: Codex <noreply@openai.com>
