Update validate_upload error message to use database max_upload_size_mb setting

- Error message now shows correct maximum file size from database setting
- Consistent with other validation functions using the same setting

app/upload/file_handler.py

@@ -73,8 +73,11 @@ class FileUploadHandler:
             file.seek(0)
             
             if not validate_file_size(file_size):
-                max_size_mb = current_app.config.get('MAX_CONTENT_LENGTH', 5 * 1024 * 1024 * 1024) // (1024 * 1024)
-                return False, f"File too large. Maximum size: {max_size_mb}MB"
+                file_size_mb = file_size // (1024*1024)
+                # Get max upload size from database settings (in MB)
+                from app.models import SystemSettings
+                max_upload_size_mb = SystemSettings.get_setting('max_upload_size_mb', 2048)  # Default 2GB
+                return False, f"File too large ({file_size_mb}MB). Maximum size: {max_upload_size_mb}MB"
             
             return True, None