Each file is now cleaned before conversion: HTML comments are removed
and everything above the configurable Draft marker (default
"### Rough Draft:") is dropped. A "# Title:" line becomes the chapter
heading and a "# Slug:" line becomes an italic caption beneath it.
- new preprocess module (strip_comments + header parse) with tests
- Chapter gains a slug rendered via a Chapter_20_Caption style, italic
at both paragraph-style and character-run level
- draft_marker config setting + top-bar field
- export title priority: override > # Title: > first # heading > filename
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>