LangChain & LangGraph 1.0 alpha releases

Alpha releases for LangChain v1.0 and LangGraph v1.0 are now available for both Python and JavaScript. LangGraph is a low-level framework for orchestrating complex agentic systems, offering features like durable execution and human-in-the-loop patterns. The new LangChain 1.0 release focuses on a core agent abstraction built on top of LangGraph, with older components being moved to a separate `langchain-legacy` package. LangChain Core is also being updated to support more structured message formats from modern LLM APIs, and a new centralized documentation site has been launched for the open-source projects.