This page was opened from disk or from another web server, so it cannot reach the extraction pipeline. Start the app server from the repository root and open the address it prints:
python app/server.py Floor plan workflow app: http://127.0.0.1:8765/
Or use the public instance: plan-extract.ch.
Everything runs locally in app/data/ (gitignored). Nothing is uploaded anywhere.
Logging in is not available yet. With an account you will get an API token for batch processing: many sheets at once, without the steps of this page.