Add admin console for managing users; default account is admin

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

index.html

@@ -89,6 +89,7 @@ input[type=range]::-moz-range-thumb{width:16px;height:16px;border-radius:50%;bac
 .ctl .pp{width:76px;height:76px;font-size:34px}
 .opts{display:flex;justify-content:center;gap:10px;margin:6px 0 14px}
 .pill{background:var(--surf);border:1px solid var(--bd);border-radius:99px;padding:8px 16px;font-weight:600;font-size:13.5px}
+a.pill{text-decoration:none;color:var(--fg);display:inline-block}
 .pill.on{border-color:var(--acc);color:var(--acc)}
 .chaps{background:var(--surf);border:1px solid var(--bd);border-radius:14px;overflow:hidden}
 .chaps h3{margin:0;padding:12px 16px;font-size:13px;color:var(--mut);text-transform:uppercase;letter-spacing:.06em}
@@ -116,6 +117,7 @@ input[type=range]::-moz-range-thumb{width:16px;height:16px;border-radius:50%;bac
 <header><div class="hd">
   <div class="logo"><i><svg><use href="#i-book"/></svg></i><span>Audiobooks</span></div>
   <div class="search"><svg><use href="#i-search"/></svg><input id="q" type="search" placeholder="Search title, author, series"></div>
+  <a class="pill hide" id="adminlink" href="/admin" style="padding:8px 12px">Admin</a>
   <button class="pill" id="who" title="Sign out" style="padding:8px 12px"></button>
   <select id="sort" aria-label="Sort"><option value="author">Group by author</option><option value="title">Sort by title</option><option value="recent">Recently played</option></select>
 </div></header>
@@ -389,7 +391,7 @@ const unlock = () => {
   }
 };
 ['touchend', 'click'].forEach(ev => document.addEventListener(ev, unlock, { once: true, passive: true }));
-fetch('/me').then(r => r.json()).then(m => { $('who').textContent = m.user + ' ⎋'; $('who').onclick = () => { if (confirm('Sign out ' + m.user + '?')) location.href = '/logout'; }; }).catch(() => {});
+fetch('/me').then(r => r.json()).then(m => { if (m.admin) $('adminlink').classList.remove('hide'); $('who').textContent = m.user + ' ⎋'; $('who').onclick = () => { if (confirm('Sign out ' + m.user + '?')) location.href = '/logout'; }; }).catch(() => {});
 load();
 </script>
 </body>