Refactor user account system and remove moderation integration

- Remove first_name and last_name fields from User model
- Add user deletion and social provider services
- Restructure auth serializers into separate directory
- Update avatar upload functionality and API endpoints
- Remove django-moderation integration documentation
- Add mandatory compliance enforcement rules
- Update frontend documentation with API usage examples

backend/apps/api/v1/serializers/accounts.py

@@ -857,17 +857,54 @@ class MarkNotificationsReadSerializer(serializers.Serializer):
         )
     ]
 )
-class AvatarUploadSerializer(serializers.ModelSerializer):
+class AvatarUploadSerializer(serializers.Serializer):
     """Serializer for uploading user avatar."""
 
-    class Meta:
-        model = UserProfile
-        fields = ["avatar"]
+    # Use FileField instead of ImageField to bypass Django's image validation
+    avatar = serializers.FileField()
 
     def validate_avatar(self, value):
         """Validate avatar file."""
-        if value:
-            # Add any avatar-specific validation here
-            # The CloudflareImagesField will handle the upload
+        if not value:
+            raise serializers.ValidationError("No file provided")
+
+        # Check file size constraints (max 10MB for Cloudflare Images)
+        if hasattr(value, 'size') and value.size > 10 * 1024 * 1024:
+            raise serializers.ValidationError(
+                "Image file too large. Maximum size is 10MB.")
+
+        # Try to validate with PIL
+        try:
+            from PIL import Image
+            import io
+
+            value.seek(0)
+            image_data = value.read()
+            value.seek(0)  # Reset for later use
+
+            if len(image_data) == 0:
+                raise serializers.ValidationError("File appears to be empty")
+
+            # Try to open with PIL
+            image = Image.open(io.BytesIO(image_data))
+
+            # Verify it's a valid image
+            image.verify()
+
+            # Check image dimensions (max 12,000x12,000 for Cloudflare Images)
+            if image.size[0] > 12000 or image.size[1] > 12000:
+                raise serializers.ValidationError(
+                    "Image dimensions too large. Maximum is 12,000x12,000 pixels.")
+
+            # Check if it's a supported format
+            if image.format not in ['JPEG', 'PNG', 'GIF', 'WEBP']:
+                raise serializers.ValidationError(
+                    f"Unsupported image format: {image.format}. Supported formats: JPEG, PNG, GIF, WebP.")
+
+        except serializers.ValidationError:
+            raise  # Re-raise validation errors
+        except Exception as e:
+            # PIL validation failed, but let Cloudflare Images try to process it
             pass
+
         return value