fix(ocr-pipeline): add libgl1 for RapidOCR OpenCV dependency

RapidOCR pulls in full opencv-python which requires libGL.so.1

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

klausur-service/Dockerfile.base

@@ -14,6 +14,8 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
     tesseract-ocr \
     tesseract-ocr-deu \
     tesseract-ocr-eng \
+    libgl1 \
+    libglib2.0-0 \
     && rm -rf /var/lib/apt/lists/*
 
 # Python dependencies