Add nltk_data volume to persist NLTK resources across restarts

docker-compose.yml

@@ -16,6 +16,7 @@ services:
       - ./backend:/app/backend:ro
       - ./src:/app/src:ro
       - ./scripts:/app/scripts:ro
+      - nltk_data:/root/nltk_data
     restart: unless-stopped
     entrypoint: ["uvicorn"]
     command: ["backend.main:app", "--host", "0.0.0.0", "--port", "8000"]
@@ -30,3 +31,4 @@ volumes:
   uploads:
   processed:
   tmp:
+  nltk_data: