Support tracing

[iamfiscus]

It would be awesome to support tracing LangchainCallbackHandler in the Node SDK:
https://portkey.ai/docs/integrations/agents/langgraph#5-traces

https://github.com/Portkey-AI/portkey-python-sdk/blob/2562d1ebfa7e7b99b6a59a3f5e5887aab348a334/portkey_ai/langchain/portkey_langchain_callback_handler.py#L15

[csgulati09]

We're releasing open telemetry based auto-instrumentation for all major frameworks like Langchain, Crewai etc, but we're starting with the python implementation first. The NodeJs implementation will follow in the coming month