Save to Files: copy books, free audiobooks and Verse By Verse lessons and handouts into Seafile (background job, progress, skips what is there)

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UaC9HmtHMdRP8dAbN4wAKj

public/reader.js

@@ -82,6 +82,7 @@ function rdBookMenu(b) {
   actionSheet(b.title, b.author || b.ext.toUpperCase(), [
     { icon: 'book', label: 'Open', run: () => { location.hash = '#/read/open/' + b.id; } },
     { icon: 'edit', label: 'Edit title and author', run: () => rdEditBook(b) },
+    ...(allowed('files') ? [{ icon: 'files', label: 'Save to Files', run: () => saveToFiles(b.title, { kind: 'book', id: b.id }) }] : []),
     { icon: 'dl', label: 'Download', run: () => { const a = document.createElement('a'); a.href = `/api/read/book/${b.id}/file`; a.download = b.title + '.' + b.ext; document.body.appendChild(a); a.click(); a.remove(); } },
     { icon: 'trash', label: 'Delete from library', danger: true, run: () => confirmSheet('Delete this book?', `"${b.title}" and your bookmarks, notes and highlights in it are removed.`, 'Delete', async () => {
       try { await rdApi('/book/' + b.id, { method: 'DELETE' }); toast('Deleted'); route(); } catch (e) { toast(e.message); } }) },