Set up Zep example Next JS app

[paul-paliychuk]

Summary: Created a sample Next JS showcasing Vercel AI SDK integration with Zep Memory (Cloud Version). Exposes two conversation handler routes zep-history - a pure Zep JS integration. langchain-zep-history - uses LangChain compatible classes provided by zep-js sdk for LangChain users.

Session ID is required for chat memory, the way the client pages are set up in the sample app is to look for a sessionId in search query, and set a random one if not provided.

[jaredpalmer]

Can we add another example without langchain?

[paul-paliychuk]

@jaredpalmer Hey, so I added an example just using zep and another example using zep + langchain integration (on a different route). Happy to extract non-langchain example into a separate example app.

[paul-paliychuk]

Just extracted LangChain example into next-zep-langchain app. Non-langchain integration is in next-zep app and doesn't have langchain dependency.