style: unify code formatting and import order

- Remove trailing whitespace and normalize blank lines
- Unify string quotes and line breaks for long lines
- Sort imports alphabetically across modules

nanobot/providers/openai_codex_provider.py

@@ -9,8 +9,8 @@ from typing import Any, AsyncGenerator
 
 import httpx
 from loguru import logger
-
 from oauth_cli_kit import get_token as get_codex_token
+
 from nanobot.providers.base import LLMProvider, LLMResponse, ToolCallRequest
 
 DEFAULT_CODEX_URL = "https://chatgpt.com/backend-api/codex/responses"