fix: remove problematic volume mount that caused 502 error

The ./data:/app mount was overwriting the entire /app directory
including application binaries, causing the backend to fail.

docker-compose.prod.yml

@@ -17,6 +17,7 @@ services:
     ports:
       - "${NOFX_BACKEND_PORT:-8080}:8080"
     volumes:
+      # Data directory for database (new images use data/data.db)
       - ./data:/app/data
       - ./decision_logs:/app/decision_logs
       - /etc/localtime:/etc/localtime:ro