Potential fix for code scanning alert no. 2: Information exposure through an exception

Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com>

Author: GitTimeraider

app.py

@@ -533,8 +533,8 @@ def test_backup_with_context():
                 else:
                     return f"Repository {repository.id} not found or inactive"
             except Exception as e:
-                logger.error(f"Error in test backup for repository {repository.id}: {e}")
-                return f"Error: {str(e)}"
+                logger.error(f"Error in test backup for repository {repository.id}: {e}", exc_info=True)
+                return "An internal error occurred during the backup operation."
 
     try:
         result = test_backup_with_context()