update project structure and improve scripts

backend/exceptions.py

@@ -0,0 +1,31 @@
+"""Custom exceptions for memory detection."""
+
+
+class DetectionError(Exception):
+    """Raised when detection fails."""
+    pass
+
+
+class ModelLoadError(Exception):
+    """Raised when model loading fails."""
+    pass
+
+
+class ImageProcessingError(Exception):
+    """Raised when image processing fails.""" 
+    pass
+
+
+class FileUploadError(Exception):
+    """Raised when file upload fails."""
+    pass
+
+
+class ValidationError(Exception):
+    """Raised when validation fails."""
+    pass
+
+
+class VideoProcessingError(Exception):
+    """Raised when video processing fails."""
+    pass