Question marks breaking the tooling

If a title contains a question mark, it tries to create a file on disk with a question mark. I think special characters should be replaced with _ ?

Start by locating the entry point that converts Confluence titles into filesystem filenames and reproduce the question-mark case described in the issue. Check how other special characters are handled, then confirm the chosen replacement behavior with a focused regression test; the issue is resolved when titles containing question marks no longer produce invalid filenames.

Written by the indexing model from the issue text.