Tesseract OCR + 70 Debian packages + pip dependencies are now in a
separate base image (klausur-base:latest) that is built once and reused.
A --no-cache build now only rebuilds the code layer (~seconds) instead
of re-downloading 33 MB of system packages (~9 minutes).
Rebuild base when requirements.txt or system deps change:
docker build -f klausur-service/Dockerfile.base -t klausur-base:latest klausur-service/
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>