Enhance CityBot with AI-powered, multi-tool conversational capabilities

[BhagwatiOracle]

Upgrade CityBot to an LLM-powered conversational assistant using LangChain and LangGraph to enable:

1. Natural language understanding for complex questions.
2. Conversation memory so follow-up questions retain context.
3. Local restaurant & cafe recommendations (Google Places API)
4. Web search (DuckDuckGo or Google Custom Search)
5. Direction/ Location of place
   @Jotthecode Please assign me this issue