Add OCR, Background Removal, and PDF Editor features with tests

- Implemented OCR functionality using pytesseract for image and PDF text extraction.
- Added Background Removal service using rembg for image processing.
- Developed PDF Editor service for applying text annotations to PDF files.
- Created corresponding API routes for OCR, Background Removal, and PDF Editor.
- Added frontend components for OCR and Background Removal tools.
- Integrated feature flagging for new tools, ensuring they are disabled by default.
- Implemented comprehensive unit tests for OCR service, PDF editor, and background removal.
- Updated documentation to reflect new features and usage instructions.
- Added translations for new features in English, Arabic, and French.

backend/Dockerfile

@@ -13,6 +13,10 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
     ffmpeg \
     libmagic1 \
     imagemagick \
+    tesseract-ocr \
+    tesseract-ocr-eng \
+    tesseract-ocr-ara \
+    tesseract-ocr-fra \
     curl \
     && apt-get clean \
     && rm -rf /var/lib/apt/lists/*