feat(update): floating notif + banner saat restart diperlukan

- marker .restart-required ditulis setelah update sukses
- API /admin/api/restart-required + polling 30s di sidebar
- banner di halaman Update sampai restart
- marker dihapus saat boot proses baru
- versi 0.5.19

views/admin/partials/sidebar.ejs

@@ -241,3 +241,31 @@ document.addEventListener('DOMContentLoaded', () => {
     return false;
   };
 </script>
+
+<div id="restart-fab" style="display:none;position:fixed;right:18px;bottom:84px;z-index:9999;max-width:330px">
+  <div style="background:#7c2d12;color:#fff;border:1px solid #f59e0b;border-radius:12px;padding:12px 14px;box-shadow:0 10px 30px rgba(0,0,0,.35);font-size:13px;line-height:1.45">
+    <b><i class="bi bi-exclamation-triangle-fill"></i> Billing perlu restart</b>
+    <div id="restart-fab-text" style="margin-top:4px;color:#fde68a">Update sudah diterapkan, tetapi kode lama masih berjalan.</div>
+    <a href="/admin/update" style="display:inline-block;margin-top:8px;background:#f59e0b;color:#111;font-weight:700;padding:6px 10px;border-radius:8px;text-decoration:none">Cara restart</a>
+  </div>
+</div>
+<script>
+(function () {
+  function checkRestartRequired() {
+    fetch('/admin/api/restart-required', { cache: 'no-store' })
+      .then(function (r) { return r.json(); })
+      .then(function (d) {
+        var el = document.getElementById('restart-fab');
+        if (!el) return;
+        el.style.display = (d && d.pending) ? 'block' : 'none';
+        if (d && d.pending && d.version) {
+          var t = document.getElementById('restart-fab-text');
+          if (t) t.textContent = 'Update v' + d.version + ' sudah diterapkan. Restart aplikasi agar fitur/fix baru aktif.';
+        }
+      })
+      .catch(function () {});
+  }
+  checkRestartRequired();
+  setInterval(checkRestartRequired, 30000);
+})();
+</script>

views/admin/update.ejs

@@ -23,6 +23,18 @@
       </div>
     <% } %>
 
+    <% if (typeof restartPending !== 'undefined' && restartPending) { %>
+      <div class="alert alert-d" style="display:flex;gap:10px;align-items:flex-start">
+        <i class="bi bi-exclamation-triangle-fill" style="font-size:18px;margin-top:1px"></i>
+        <div>
+          <b>Restart diperlukan.</b>
+          Update ke versi <b><%= restartPending.version || '-' %></b> sudah diterapkan ke file,
+          tetapi aplikasi masih menjalankan kode lama. Fitur/fix baru belum aktif sampai aplikasi di-restart.
+          <a href="#restart-help" style="color:inherit;text-decoration:underline;font-weight:700">Lihat cara restart</a>.
+        </div>
+      </div>
+    <% } %>
+
     <div class="card mb16">
       <div class="card-hd"><h6><i class="bi bi-git"></i> <%= t('admin.update.status_title', 'Status Versi') %></h6></div>
       <div class="card-bd">
@@ -79,7 +91,7 @@
       </div>
     </div>
 
-    <div class="card mb16">
+    <div class="card mb16" id="restart-help">
       <div class="card-hd"><h6><i class="bi bi-arrow-repeat"></i> <%= t('admin.update.restart_title', 'Cara Restart Aplikasi') %></h6></div>
       <div class="card-bd" style="display:grid;grid-template-columns:repeat(auto-fit,minmax(280px,1fr));gap:14px;font-size:12px">
         <div style="border:1px solid var(--border);border-radius:12px;padding:12px 14px;background:rgba(255,255,255,.02);line-height:1.75">