[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/_run.py

@@ -0,0 +1,112 @@
+from __future__ import annotations
+
+from dataclasses import dataclass
+from typing import AsyncIterator, Iterator
+
+from .generated.v2_all import (
+    AgentMessageThreadItem,
+    ItemCompletedNotification,
+    MessagePhase,
+    ThreadItem,
+    ThreadTokenUsage,
+    ThreadTokenUsageUpdatedNotification,
+    Turn as AppServerTurn,
+    TurnCompletedNotification,
+    TurnStatus,
+)
+from .models import Notification
+
+
+@dataclass(slots=True)
+class RunResult:
+    final_response: str | None
+    items: list[ThreadItem]
+    usage: ThreadTokenUsage | None
+
+
+def _agent_message_item_from_thread_item(
+    item: ThreadItem,
+) -> AgentMessageThreadItem | None:
+    thread_item = item.root if hasattr(item, "root") else item
+    if isinstance(thread_item, AgentMessageThreadItem):
+        return thread_item
+    return None
+
+
+def _final_assistant_response_from_items(items: list[ThreadItem]) -> str | None:
+    last_unknown_phase_response: str | None = None
+
+    for item in reversed(items):
+        agent_message = _agent_message_item_from_thread_item(item)
+        if agent_message is None:
+            continue
+        if agent_message.phase == MessagePhase.final_answer:
+            return agent_message.text
+        if agent_message.phase is None and last_unknown_phase_response is None:
+            last_unknown_phase_response = agent_message.text
+
+    return last_unknown_phase_response
+
+
+def _raise_for_failed_turn(turn: AppServerTurn) -> None:
+    if turn.status != TurnStatus.failed:
+        return
+    if turn.error is not None and turn.error.message:
+        raise RuntimeError(turn.error.message)
+    raise RuntimeError(f"turn failed with status {turn.status.value}")
+
+
+def _collect_run_result(stream: Iterator[Notification], *, turn_id: str) -> RunResult:
+    completed: TurnCompletedNotification | None = None
+    items: list[ThreadItem] = []
+    usage: ThreadTokenUsage | None = None
+
+    for event in stream:
+        payload = event.payload
+        if isinstance(payload, ItemCompletedNotification) and payload.turn_id == turn_id:
+            items.append(payload.item)
+            continue
+        if isinstance(payload, ThreadTokenUsageUpdatedNotification) and payload.turn_id == turn_id:
+            usage = payload.token_usage
+            continue
+        if isinstance(payload, TurnCompletedNotification) and payload.turn.id == turn_id:
+            completed = payload
+
+    if completed is None:
+        raise RuntimeError("turn completed event not received")
+
+    _raise_for_failed_turn(completed.turn)
+    return RunResult(
+        final_response=_final_assistant_response_from_items(items),
+        items=items,
+        usage=usage,
+    )
+
+
+async def _collect_async_run_result(
+    stream: AsyncIterator[Notification], *, turn_id: str
+) -> RunResult:
+    completed: TurnCompletedNotification | None = None
+    items: list[ThreadItem] = []
+    usage: ThreadTokenUsage | None = None
+
+    async for event in stream:
+        payload = event.payload
+        if isinstance(payload, ItemCompletedNotification) and payload.turn_id == turn_id:
+            items.append(payload.item)
+            continue
+        if isinstance(payload, ThreadTokenUsageUpdatedNotification) and payload.turn_id == turn_id:
+            usage = payload.token_usage
+            continue
+        if isinstance(payload, TurnCompletedNotification) and payload.turn.id == turn_id:
+            completed = payload
+
+    if completed is None:
+        raise RuntimeError("turn completed event not received")
+
+    _raise_for_failed_turn(completed.turn)
+    return RunResult(
+        final_response=_final_assistant_response_from_items(items),
+        items=items,
+        usage=usage,
+    )