Share songs, albums, movies, shows, podcasts and audiobooks to chat as cards

A share message carries kind, title, subtitle, same-origin art and a hash-route
link, validated on the server. It counts as unread, reads as '🎵 Shared a song:
Title' in pushes and Notifications, and is found by search. In Chat a card opens
the item, or says it is not available when the recipient lacks that tab.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

public/audiobooks-view.js

@@ -92,15 +92,17 @@ async function viewBooks(args = []) {
   const byId = new Map(abBooks.map(b => [abId(b), b]));
   v.onclick = e => { const c = e.target.closest('button[data-id]'); if (c) abSheet(byId.get(c.dataset.id)); };
   lvBind(v, () => route());
+  if (args[0] === 'book' && args[1]) { const bid = args[1], b0 = /^lv:/.test(bid) ? null : byId.get(bid); if (/^lv:/.test(bid)) lvSheet(bid.slice(3)); else if (b0) abSheet(b0); else toast('That book is not in your library'); } // (a link from a Chat share card)
 }
 
 function abSheet(b) {
   const id = abId(b), p = abProg[id], left = p && p.dur ? p.dur - p.pos : 0, resumable = p && p.pos > 10 && p.dur && p.pos < p.dur - 30;
   const el = openSheet(abTitle(b), [abAuthor(b), abSeries(b)].filter(Boolean).join(' · '), `<div style="display:flex;gap:14px;align-items:flex-start"><span class="vimg" style="width:96px;flex:none;aspect-ratio:1/1"><img alt="" src="${abCover(b)}" onerror="this.remove()"></span>
       <div style="min-width:0"><p class="sub" style="margin:0">${resumable ? esc(abFmt(p.pos) + ' of ' + abFmt(p.dur) + ' · ' + abFmt(left) + ' left') : p && p.dur && p.pos >= p.dur - 30 ? 'Finished' : 'Not started'}</p></div></div>
-    <div class="bar"><button class="btn" id="abp">${icon('play')}${resumable ? 'Resume' : 'Play'}</button>${resumable ? '<button class="btn ghost" id="abs">From the start</button>' : ''}<button class="btn ghost" id="abc">Chapters</button></div><div class="err" id="abe"></div><div id="abch" class="list" style="max-height:40vh;overflow:auto"></div>`);
+    <div class="bar"><button class="btn" id="abp">${icon('play')}${resumable ? 'Resume' : 'Play'}</button>${resumable ? '<button class="btn ghost" id="abs">From the start</button>' : ''}<button class="btn ghost" id="abc">Chapters</button>${allowed('chat') ? `<button class="btn ghost" id="abh">${icon('send')}Share</button>` : ''}</div><div class="err" id="abe"></div><div id="abch" class="list" style="max-height:40vh;overflow:auto"></div>`);
   const go = async at => { try { await abPlay(b, at); closeSheet(); } catch (e) { el.querySelector('#abe').textContent = e.message; } };
   el.querySelector('#abp').onclick = () => go();
+  if (el.querySelector('#abh')) el.querySelector('#abh').onclick = () => { closeSheet(); shareMedia({ kind: 'audiobook', title: abTitle(b), sub: abAuthor(b), art: abCover(b), link: '#/audio/book/' + encodeURIComponent(id) }); };
   if (el.querySelector('#abs')) el.querySelector('#abs').onclick = () => go(0);
   el.querySelector('#abc').onclick = async () => {
     const box = el.querySelector('#abch'); box.innerHTML = '<p class="empty">Loading…</p>';