[2/6] Generate Python SDK types from pinned runtime

[aibrahim-oai]

Stack

• [1/6] [1/6] Pin Python SDK runtime dependency #21891 Pin Python SDK runtime dependency
• [2/6] [2/6] Generate Python SDK types from pinned runtime #21893 Generate Python SDK types from pinned runtime
• [3/6] [3/6] Run Python SDK tests in CI #21895 Run Python SDK tests in CI
• [4/6] [4/6] Define Python SDK public API surface #21896 Define Python SDK public API surface
• [5/6] [5/6] Rename Python SDK package to openai-codex #21905 Rename Python SDK package to openai-codex
• [6/6] [6/6] Default Python SDK approval policy to never #21910 Default Python SDK approval policy to never

This PR is the second change in the stack, on top of #21891.

Why

Once the SDK has a declared runtime dependency, generated Python API/types should come from that pinned runtime instead of the app-server schema in the current checkout. That keeps checked-in generated artifacts aligned with the runtime package users install.

What changed

• Make scripts/update_sdk_artifacts.py generate-types invoke the pinned runtime package to emit schema.
• Regenerate v2_all.py, notification_registry.py, and generated api.py from that schema.
• Update tests so generated artifacts are checked for freshness against the pinned runtime.

Verification

• CI is running on this PR stack.
• Local structural checks before submitting: git diff --check and workflow YAML parse.

[aibrahim-oai]

This change is part of the following stack:

• Publish Python runtime wheels on release #21812
  • [1/6] Pin Python SDK runtime dependency #21891
    • [2/6] Generate Python SDK types from pinned runtime #21893 ◀

_{Change managed by git-spice.}