Add support for local-ai model use in agent-demo-app #871

As a developer wanting to use the agent-demo-app template I want to be able to use a local ai model so that I don't have to use my api credits to test out the agent framework

Tasks

• Add support for specifying a baseURL to support OpenAI and Anthropic Compatible local AI platforms (Ollama, LM Studio, etc...). Most providers support both the Chat completions and Messages API formats