fix: add missing pytz dependency and remove ollama port conflict

- Add pytz to trading extras (alpaca-py requires it but doesn't declare it)
- Remove host port mapping from ollama container to avoid conflict with
  local ollama instance

docker-compose.yml

@@ -32,8 +32,6 @@ services:
 
   ollama:
     image: ollama/ollama:latest
-    ports:
-      - "127.0.0.1:11434:11434"
     volumes:
       - ollama_models:/root/.ollama