fix(providers): validate stream idle timeout config

nanobot/providers/openai_codex_provider.py

@@ -5,7 +5,6 @@ from __future__ import annotations
 import asyncio
 import hashlib
 import json
-import os
 from collections.abc import Awaitable, Callable
 from typing import Any
 
@@ -13,7 +12,12 @@ 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
+from nanobot.providers.base import (
+    LLMProvider,
+    LLMResponse,
+    ToolCallRequest,
+    resolve_stream_idle_timeout_s,
+)
 from nanobot.providers.openai_responses import (
     consume_sse_with_reasoning,
     convert_messages,
@@ -199,7 +203,7 @@ async def _request_codex(
     on_thinking_delta: Callable[[str], Awaitable[None]] | None = None,
     on_tool_call_delta: Callable[[dict[str, Any]], Awaitable[None]] | None = None,
 ) -> tuple[str, list[ToolCallRequest], str, dict[str, int], str | None]:
-    idle_timeout_s = int(os.environ.get("NANOBOT_STREAM_IDLE_TIMEOUT_S", "90"))
+    idle_timeout_s = resolve_stream_idle_timeout_s()
     async with httpx.AsyncClient(timeout=idle_timeout_s, verify=verify) as client:
         async with client.stream("POST", url, headers=headers, json=body) as response:
             if response.status_code != 200: