fix: remove MinIO references from client docstrings

The silo server now uses filesystem storage instead of MinIO.
Update docstrings in _download_file() and has_file() to reflect
the current storage architecture.

silo_client/__init__.py

@@ -171,7 +171,7 @@ class SiloClient:
         dest_path: str,
         progress_callback=None,
     ) -> bool:
-        """Download a file from MinIO storage.
+        """Download a revision file from the server.
 
         Args:
             progress_callback: Optional ``callable(bytes_downloaded, total_bytes)``.
@@ -629,7 +629,7 @@ class SiloClient:
         return self._request("POST", f"/items/{pn}/revisions", data)
 
     def has_file(self, part_number: str) -> Tuple[bool, Optional[int]]:
-        """Check if item has files in storage."""
+        """Check if any revision of this item has an associated file."""
         try:
             revisions = self.get_revisions(part_number)
             for rev in revisions: