curl -X POST http://localhost:18080/api/chat \
  -H "Content-Type: application/json" \
  -d '{
    "message": "How many steps did I take yesterday?",
    "user_id": "user_123",
    "session_id": "session_abc"
  }'

{
  "response": "Based on your Garmin data, you took 10,543 steps yesterday. That's about 200 steps more than your daily average!",
  "session_id": "session_abc",
  "timestamp": "2024-01-15T10:30:00Z",
  "provider": "openai",
  "model": "gpt-4"
}