[5/8] Rename Python SDK package to openai-codex (#21905)

## Why

The SDK should publish under the reserved public distribution name
`openai-codex`, and its import module should match that name in the
Python style. Since package names can contain hyphens but import modules
cannot, the public import path becomes `openai_codex`.

Keeping the rename separate from the public API surface change makes the
naming change easy to review and avoids mixing it with API curation.

## What

- Rename the SDK distribution from `openai-codex-app-server-sdk` to
`openai-codex`.
- Rename the import package from `codex_app_server` to `openai_codex`.
- Keep the runtime wheel as the separate `openai-codex-cli-bin`
dependency.
- Update docs, examples, notebooks, artifact scripts, lockfile metadata,
and tests for the new distribution/module names.

## Stack

1. #21891 `[1/8]` Pin Python SDK runtime dependency
2. #21893 `[2/8]` Generate Python SDK types from pinned runtime
3. #21895 `[3/8]` Run Python SDK tests in CI
4. #21896 `[4/8]` Define Python SDK public API surface
5. This PR `[5/8]` Rename Python SDK package to `openai-codex`
6. #21910 `[6/8]` Add high-level Python SDK approval mode
7. #22014 `[7/8]` Add Python SDK app-server integration harness
8. #22021 `[8/8]` Add Python SDK Ruff formatting

## Verification

- Updated package metadata and public API tests to assert the
distribution and import names.

Co-authored-by: Codex <noreply@openai.com>

sdk/python/tests/test_artifact_workflow_and_binaries.py

@@ -172,12 +172,12 @@ def test_examples_readme_points_to_runtime_version_source_of_truth() -> None:
 def test_runtime_distribution_name_is_consistent() -> None:
     script = _load_update_script_module()
     runtime_setup = _load_runtime_setup_module()
-    from codex_app_server import client as client_module
-    from codex_app_server import _version
+    from openai_codex import client as client_module
+    from openai_codex import _version
 
-    assert script.SDK_DISTRIBUTION_NAME == "openai-codex-app-server-sdk"
-    assert runtime_setup.SDK_PACKAGE_NAME == "openai-codex-app-server-sdk"
-    assert _version.DISTRIBUTION_NAME == "openai-codex-app-server-sdk"
+    assert script.SDK_DISTRIBUTION_NAME == "openai-codex"
+    assert runtime_setup.SDK_PACKAGE_NAME == "openai-codex"
+    assert _version.DISTRIBUTION_NAME == "openai-codex"
     assert script.RUNTIME_DISTRIBUTION_NAME == "openai-codex-cli-bin"
     assert runtime_setup.PACKAGE_NAME == "openai-codex-cli-bin"
     assert client_module.RUNTIME_PKG_NAME == "openai-codex-cli-bin"
@@ -457,18 +457,18 @@ def test_stage_sdk_release_injects_exact_runtime_pin(tmp_path: Path) -> None:
     )
 
     pyproject = (staged / "pyproject.toml").read_text()
-    assert 'name = "openai-codex-app-server-sdk"' in pyproject
+    assert 'name = "openai-codex"' in pyproject
     assert 'version = "0.116.0a1"' in pyproject
     assert '"openai-codex-cli-bin==0.116.0a1"' in pyproject
     assert (
         '__version__ = "0.116.0a1"'
-        not in (staged / "src" / "codex_app_server" / "__init__.py").read_text()
+        not in (staged / "src" / "openai_codex" / "__init__.py").read_text()
     )
     assert (
         'client_version: str = "0.116.0a1"'
-        not in (staged / "src" / "codex_app_server" / "client.py").read_text()
+        not in (staged / "src" / "openai_codex" / "client.py").read_text()
     )
-    assert not any((staged / "src" / "codex_app_server").glob("bin/**"))
+    assert not any((staged / "src" / "openai_codex").glob("bin/**"))
 
 
 def test_stage_sdk_release_replaces_existing_staging_dir(tmp_path: Path) -> None:
@@ -637,7 +637,7 @@ def test_stage_runtime_stages_binary_without_type_generation(tmp_path: Path) ->
 def test_default_runtime_is_resolved_from_installed_runtime_package(
     tmp_path: Path,
 ) -> None:
-    from codex_app_server import client as client_module
+    from openai_codex import client as client_module
 
     fake_binary = tmp_path / ("codex.exe" if client_module.os.name == "nt" else "codex")
     fake_binary.write_text("")
@@ -652,7 +652,7 @@ def test_default_runtime_is_resolved_from_installed_runtime_package(
 
 
 def test_explicit_codex_bin_override_takes_priority(tmp_path: Path) -> None:
-    from codex_app_server import client as client_module
+    from openai_codex import client as client_module
 
     explicit_binary = tmp_path / (
         "custom-codex.exe" if client_module.os.name == "nt" else "custom-codex"
@@ -670,7 +670,7 @@ def test_explicit_codex_bin_override_takes_priority(tmp_path: Path) -> None:
 
 
 def test_missing_runtime_package_requires_explicit_codex_bin() -> None:
-    from codex_app_server import client as client_module
+    from openai_codex import client as client_module
 
     ops = client_module.CodexBinResolverOps(
         installed_codex_path=lambda: (_ for _ in ()).throw(
@@ -684,7 +684,7 @@ def test_missing_runtime_package_requires_explicit_codex_bin() -> None:
 
 
 def test_broken_runtime_package_does_not_fall_back() -> None:
-    from codex_app_server import client as client_module
+    from openai_codex import client as client_module
 
     ops = client_module.CodexBinResolverOps(
         installed_codex_path=lambda: (_ for _ in ()).throw(