Rename Python SDK package to openai-codex

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

sdk/python/examples/11_cli_mini_app/async.py

@@ -11,11 +11,11 @@ ensure_local_sdk_src()
 
 import asyncio
 
-from codex_app_server import (
+from openai_codex import (
     AsyncCodex,
     TextInput,
 )
-from codex_app_server.types import (
+from openai_codex.types import (
     ThreadTokenUsageUpdatedNotification,
     TurnCompletedNotification,
 )