fix(llm): replace hard coded local Ollama with OLLAMA_HOST

[sammcj]

No description provided.

[carlvaneijk]

This is a trivial change. Please merge!

Perhaps just an if like this to make it more robust

default_endpoint = "http://localhost:11434/api/generate"
ollama_host = os.getenv("OLLAMA_HOST")

if ollama_host:
self.model_endpoint = ollama_host + "/api/generate"
else:
self.model_endpoint = default_endpoint