[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/docs/api-reference.md

@@ -1,13 +1,13 @@
-# Codex App Server SDK — API Reference
+# OpenAI Codex SDK — API Reference
 
-Public surface of `codex_app_server` for app-server v2.
+Public surface of `openai_codex` for app-server v2.
 
 This SDK surface is experimental. Turn streams are routed by turn ID so one client can consume multiple active turns concurrently.
 
 ## Package Entry
 
 ```python
-from codex_app_server import (
+from openai_codex import (
     Codex,
     AsyncCodex,
     RunResult,
@@ -23,7 +23,7 @@ from codex_app_server import (
     SkillInput,
     MentionInput,
 )
-from codex_app_server.types import (
+from openai_codex.types import (
     InitializeResponse,
     ThreadItem,
     ThreadTokenUsage,
@@ -31,9 +31,9 @@ from codex_app_server.types import (
 )
 ```
 
-- Version: `codex_app_server.__version__`
+- Version: `openai_codex.__version__`
 - Requires Python >= 3.10
-- Public app-server value and event types live in `codex_app_server.types`
+- Public app-server value and event types live in `openai_codex.types`
 
 ## Codex (sync)
 
@@ -136,7 +136,7 @@ Use `turn(...)` when you need low-level turn control (`stream()`, `steer()`,
 - `steer(input: Input) -> TurnSteerResponse`
 - `interrupt() -> TurnInterruptResponse`
 - `stream() -> Iterator[Notification]`
-- `run() -> codex_app_server.types.Turn`
+- `run() -> openai_codex.types.Turn`
 
 Behavior notes:
 
@@ -148,7 +148,7 @@ Behavior notes:
 - `steer(input: Input) -> Awaitable[TurnSteerResponse]`
 - `interrupt() -> Awaitable[TurnInterruptResponse]`
 - `stream() -> AsyncIterator[Notification]`
-- `run() -> Awaitable[codex_app_server.types.Turn]`
+- `run() -> Awaitable[openai_codex.types.Turn]`
 
 Behavior notes:
 
@@ -173,7 +173,7 @@ Input = list[InputItem] | InputItem
 The SDK wrappers return and accept public app-server models wherever possible:
 
 ```python
-from codex_app_server.types import (
+from openai_codex.types import (
     AskForApproval,
     ThreadReadResponse,
     Turn,
@@ -184,7 +184,7 @@ from codex_app_server.types import (
 ## Retry + errors
 
 ```python
-from codex_app_server import (
+from openai_codex import (
     retry_on_overload,
     JsonRpcError,
     MethodNotFoundError,
@@ -200,7 +200,7 @@ from codex_app_server import (
 ## Example
 
 ```python
-from codex_app_server import Codex
+from openai_codex import Codex
 
 with Codex() as codex:
     thread = codex.thread_start(model="gpt-5.4", config={"model_reasoning_effort": "high"})