[2/8] Generate Python SDK types from pinned runtime

[aibrahim-oai]

Why

Once the SDK declares its runtime package, generated Python artifacts should come from that pinned runtime rather than whatever app-server schema happens to be in the current checkout. That keeps the generated API and model surface aligned with the runtime users install.

What

• Teach scripts/update_sdk_artifacts.py generate-types to invoke the pinned runtime package for schema generation.
• Regenerate v2_all.py, notification_registry.py, and generated public wrapper methods from that schema.
• Add freshness coverage so regenerating from the pinned runtime must leave checked-in artifacts unchanged.

Stack

1. [1/8] Pin Python SDK runtime dependency #21891 [1/8] Pin Python SDK runtime dependency
2. This PR [2/8] Generate Python SDK types from pinned runtime
3. [3/8] Run Python SDK tests in CI #21895 [3/8] Run Python SDK tests in CI
4. [4/8] Define Python SDK public API surface #21896 [4/8] Define Python SDK public API surface
5. [5/8] Rename Python SDK package to openai-codex #21905 [5/8] Rename Python SDK package to openai-codex
6. [6/8] Add high-level Python SDK approval mode #21910 [6/8] Add high-level Python SDK approval mode
7. [7/8] Add Python SDK app-server integration harness #22014 [7/8] Add Python SDK app-server integration harness
8. [8/8] Add Python SDK Ruff formatting #22021 [8/8] Add Python SDK Ruff formatting

Verification

• Added test_generated_files_are_up_to_date for pinned-runtime generation drift.
• Added generator-structure tests for schema annotation and notification metadata generation.

[aibrahim-oai]

This change is part of the following stack:

• Publish Python runtime wheels on release #21812
  • [1/8] Pin Python SDK runtime dependency #21891
    • [2/8] Generate Python SDK types from pinned runtime #21893 ◀

_{Change managed by git-spice.}