Fix test failures and workload/websocket behavior

backend/app/services/file_storage_service.py

@@ -33,6 +33,8 @@ class FileStorageService:
 
     def __init__(self):
         self.base_dir = Path(settings.UPLOAD_DIR).resolve()
+        # Backward-compatible attribute name for tests and older code
+        self.upload_dir = self.base_dir
         self._storage_status = {
             "validated": False,
             "path_exists": False,
@@ -217,15 +219,16 @@ class FileStorageService:
             PathTraversalError: If the path is outside the base directory
         """
         resolved_path = path.resolve()
+        base_dir = self.base_dir.resolve()
 
         # Check if the resolved path is within the base directory
         try:
-            resolved_path.relative_to(self.base_dir)
+            resolved_path.relative_to(base_dir)
         except ValueError:
             logger.warning(
                 "Path traversal attempt detected: path %s is outside base directory %s. Context: %s",
                 resolved_path,
-                self.base_dir,
+                base_dir,
                 context
             )
             raise PathTraversalError(