- bookmark button 🔖 in toolbar (Ctrl+B / Cmd+B shortcut)
- addBookmark() saves current position (CFI for epub, page for pdf, scroll% for text)
- bookmarks stored in localStorage per-file (bookish_bookmarks_<filename>)
- sidebar Segnalibri tab shows clickable list with delete button
- gotoBookmark() restores the exact position per format type
- CSS styles for bm-entry, bm-label, bm-time, bm-delete