Fix Dockerfile npm permissions and mermaid-cli usage: Use npx instead of global install

Fix npm engine warnings: Upgrade Node.js base image from 18 to 20

Fix Dockerfile npm permissions: Use user directory for npm packages and update PATH

Fix Dockerfile user ID conflict: Change UID from 1000 to 1001

Fix app_port for Hugging Face Spaces: Change to 7860 and update all related configurations

Update for Docker Spaces best practices: Add app_port to README.md and improve Dockerfile with user permissions

Update for Hugging Face Spaces deployment: Change port to 80 and update documentation

Add healthz endpoint and increase Gunicorn timeout

latest changes