Dockerfile: Add system dependencies for Unstructured.io PDF processing

- Add poppler-utils for PDF processing (resolves 'pdfinfo not found' error)
- Add tesseract-ocr for OCR capabilities
- Add libmagic1 for file type detection
- These dependencies are required for full Unstructured.io functionality

Dockerfile

@@ -122,6 +122,9 @@ RUN apt-get update && \
     git build-essential pandoc gcc netcat-openbsd curl jq \
     python3-dev \
     ffmpeg libsm6 libxext6 \
+    poppler-utils \
+    tesseract-ocr \
+    libmagic1 \
     && rm -rf /var/lib/apt/lists/*
 
 # install python dependencies