Add AI Agent sample console app

[MaryanneNjeri]

This PR

Adds the AI agent sample console app, that we will include in the AI Agent configuration doc. The agent is created declaratively check out creating agents declaratively for more information.

Yaml agent spec used for this sample

 kind: Prompt
 name: ChatAgent
 description: Agent example with web search
 instructions: You are a helpful assistant with access to web search.
 model:
     id: gpt-4.1
     connection:
         kind: remote
 tools:
   - kind: web_search
     name: WebSearchTool
     description: Search the web for live information.