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/app/services/removebg_service.py

@@ -0,0 +1,60 @@
+"""Background removal service using rembg."""
+import logging
+import os
+
+from PIL import Image
+
+logger = logging.getLogger(__name__)
+
+
+class RemoveBGError(Exception):
+    """Custom exception for background removal failures."""
+    pass
+
+
+def remove_background(input_path: str, output_path: str) -> dict:
+    """Remove the background from an image.
+
+    Args:
+        input_path: Path to the input image.
+        output_path: Path for the output PNG (always PNG — transparency).
+
+    Returns:
+        dict with ``original_size``, ``output_size``, ``width``, ``height``.
+
+    Raises:
+        RemoveBGError: If the operation fails.
+    """
+    os.makedirs(os.path.dirname(output_path), exist_ok=True)
+
+    try:
+        from rembg import remove as rembg_remove
+
+        with Image.open(input_path) as img:
+            if img.mode != "RGBA":
+                img = img.convert("RGBA")
+            width, height = img.size
+            original_size = os.path.getsize(input_path)
+
+            result = rembg_remove(img)
+            result.save(output_path, format="PNG", optimize=True)
+
+        output_size = os.path.getsize(output_path)
+
+        logger.info(
+            "Background removed: %s → %s (%d → %d bytes)",
+            input_path, output_path, original_size, output_size,
+        )
+
+        return {
+            "original_size": original_size,
+            "output_size": output_size,
+            "width": width,
+            "height": height,
+        }
+    except ImportError:
+        raise RemoveBGError("rembg is not installed.")
+    except (IOError, OSError) as e:
+        raise RemoveBGError(f"Background removal failed: {str(e)}")
+    except Exception as e:
+        raise RemoveBGError(f"Background removal failed: {str(e)}")