PyPI - LangChain NEAR Integration

Context: A dedicated package for LangChain + NEAR that bundles all the tools. One-line installation for complete NEAR and marketplace integration in any LangChain project.

Deliverables:

1. PyPI package langchain-near:

   from langchain_near import NEARToolkit
   
   toolkit = NEARToolkit()
   agent = create_react_agent(llm, toolkit.get_tools())
   # Agent can now: search marketplace, compare gas, deploy contracts, earn NEAR
   

2. All tools from Tasks 12-15 bundled
3. Ready-to-use agent examples
4. PUBLISHED TO:
   • PyPI with LangChain classifiers
   • LangChain integration docs PR
   • LangChain Discord showcase

Success Metric: Recommended way to add NEAR to LangChain