[Subtask] Handle file name encoding and special characters.

### Describe the subtask

In different client environments, file name encoding and the special characters within them need to be handled to ensure correct file operations and avoid garbled text.

### Parent issue

#5504

Start with parent issue #5504 and trace the client-environment file-operation path described there. Identify the affected entry points and existing tests for filename encoding and special characters; done means filenames are handled without garbled text across the stated client environments.

Written by the indexing model from the issue text.