def create_langfuse_handler() -> Any | None:
    """Return a configured handler when credentials are available."""
    if not os.getenv("LANGFUSE_PUBLIC_KEY") or not os.getenv("LANGFUSE_SECRET_KEY"):
        return None
    from langfuse.langchain import CallbackHandler

    return CallbackHandler()

def flush_langfuse(handler: Any | None) -> None:
    """Upload queued telemetry without making observability application-critical."""
    if handler is None:
        return
    try:
        from langfuse import get_client

        get_client().flush()
    except Exception:
        logger.exception("Failed to flush LangFuse telemetry")