update project structure and improve scripts

backend/utils.py

@@ -0,0 +1,40 @@
+import os
+import logging
+from pathlib import Path
+
+
+def allowed_file(filename, allowed_extensions):
+    """Check if file extension is allowed."""
+    return '.' in filename and \
+           filename.rsplit('.', 1)[1].lower() in allowed_extensions
+
+
+def setup_logging():
+    """Setup simple logging configuration."""
+    # Create logs directory
+    log_dir = Path('logs')
+    log_dir.mkdir(exist_ok=True)
+    
+    # Configure logging
+    logging.basicConfig(
+        level=logging.INFO,
+        format='%(asctime)s - %(name)s - %(levelname)s - %(message)s',
+        handlers=[
+            logging.FileHandler('logs/app.log'),
+            logging.StreamHandler()
+        ]
+    )
+    
+    # Set levels for noisy libraries
+    logging.getLogger('werkzeug').setLevel(logging.WARNING)
+    logging.getLogger('ultralytics').setLevel(logging.WARNING)
+
+
+def validate_image_size(file_size, max_size):
+    """Validate image file size."""
+    return file_size <= max_size
+
+
+def get_file_extension(filename):
+    """Get file extension from filename."""
+    return filename.rsplit('.', 1)[1].lower() if '.' in filename else ''