Fix: force list_repo_tree generator inside try/except

list_repo_tree returns a lazy generator — the HTTP request fires during
iteration, not on the call itself, so wrapping only the call did not catch
the 404. Wrapping list() forces evaluation inside the try block.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

logging_utils.py

@@ -87,7 +87,7 @@ def _make_path(now, uid):
 
 def _list_existing_files(api, repo_id):
     try:
-        entries = api.list_repo_tree(repo_id, repo_type="dataset", path_in_repo="data")
+        entries = list(api.list_repo_tree(repo_id, repo_type="dataset", path_in_repo="data"))
     except Exception as e:
         print(f"[log] could not list existing files (empty repo?): {e}")
         return []