[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/src/openai_codex/models.py

@@ -0,0 +1,99 @@
+from __future__ import annotations
+
+from dataclasses import dataclass
+from typing import TypeAlias
+
+from pydantic import BaseModel
+
+from .generated.v2_all import (
+    AccountLoginCompletedNotification,
+    AccountRateLimitsUpdatedNotification,
+    AccountUpdatedNotification,
+    AgentMessageDeltaNotification,
+    AppListUpdatedNotification,
+    CommandExecutionOutputDeltaNotification,
+    ConfigWarningNotification,
+    ContextCompactedNotification,
+    DeprecationNoticeNotification,
+    ErrorNotification,
+    FileChangeOutputDeltaNotification,
+    ItemCompletedNotification,
+    ItemStartedNotification,
+    McpServerOauthLoginCompletedNotification,
+    McpToolCallProgressNotification,
+    PlanDeltaNotification,
+    RawResponseItemCompletedNotification,
+    ReasoningSummaryPartAddedNotification,
+    ReasoningSummaryTextDeltaNotification,
+    ReasoningTextDeltaNotification,
+    TerminalInteractionNotification,
+    ThreadNameUpdatedNotification,
+    ThreadStartedNotification,
+    ThreadTokenUsageUpdatedNotification,
+    TurnCompletedNotification,
+    TurnDiffUpdatedNotification,
+    TurnPlanUpdatedNotification,
+    TurnStartedNotification,
+    WindowsWorldWritableWarningNotification,
+)
+
+JsonScalar: TypeAlias = str | int | float | bool | None
+JsonValue: TypeAlias = JsonScalar | dict[str, "JsonValue"] | list["JsonValue"]
+JsonObject: TypeAlias = dict[str, JsonValue]
+
+
+@dataclass(slots=True)
+class UnknownNotification:
+    params: JsonObject
+
+
+NotificationPayload: TypeAlias = (
+    AccountLoginCompletedNotification
+    | AccountRateLimitsUpdatedNotification
+    | AccountUpdatedNotification
+    | AgentMessageDeltaNotification
+    | AppListUpdatedNotification
+    | CommandExecutionOutputDeltaNotification
+    | ConfigWarningNotification
+    | ContextCompactedNotification
+    | DeprecationNoticeNotification
+    | ErrorNotification
+    | FileChangeOutputDeltaNotification
+    | ItemCompletedNotification
+    | ItemStartedNotification
+    | McpServerOauthLoginCompletedNotification
+    | McpToolCallProgressNotification
+    | PlanDeltaNotification
+    | RawResponseItemCompletedNotification
+    | ReasoningSummaryPartAddedNotification
+    | ReasoningSummaryTextDeltaNotification
+    | ReasoningTextDeltaNotification
+    | TerminalInteractionNotification
+    | ThreadNameUpdatedNotification
+    | ThreadStartedNotification
+    | ThreadTokenUsageUpdatedNotification
+    | TurnCompletedNotification
+    | TurnDiffUpdatedNotification
+    | TurnPlanUpdatedNotification
+    | TurnStartedNotification
+    | WindowsWorldWritableWarningNotification
+    | UnknownNotification
+)
+
+
+@dataclass(slots=True)
+class Notification:
+    method: str
+    payload: NotificationPayload
+
+
+class ServerInfo(BaseModel):
+    name: str | None = None
+    version: str | None = None
+
+
+class InitializeResponse(BaseModel):
+    serverInfo: ServerInfo | None = None
+    userAgent: str | None = None
+    platformFamily: str | None = None
+    platformOs: str | None = None