feat(desktop): in-app prompt to restart for an update

The main process already showed a system notification when an update finished
downloading, and nothing in the renderer listened — so the only cue vanished on
its own and was missed by anyone not watching the desktop at that moment.

A prompt now stays in the window until it is acted on or dismissed, with the
restart wired to the install-update channel the preload already exposed.

Dismissing is 'not now', not 'never': a later version reopens the prompt, since
the version it refers to has changed.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

packages/web/src/components/layout/AppLayout.tsx

@@ -1,4 +1,5 @@
 import React, { useEffect } from 'react';
+import { UpdateBanner } from '../ui/UpdateBanner';
 import { useExpressionStore } from '../../stores/expressionStore';
 import { useParams, useNavigate } from 'react-router-dom';
 import { SpaceSidebar } from './SpaceSidebar';
@@ -428,6 +429,7 @@ export function AppLayout() {
             (e.g. immediately after Join, or after popping voice-full back to
             the root). */}
         <SoundController />
+        <UpdateBanner />
         <GlobalAudioRenderer />
         <NotificationController />
         <UpdateToast />

packages/web/src/components/ui/UpdateBanner.tsx

@@ -0,0 +1,53 @@
+import { useEffect, useState } from 'react';
+import { isElectron } from '../../platform/platform';
+import { useT } from '../../i18n';
+
+/**
+ * Aviso de que uma atualização já baixou e só falta reiniciar.
+ *
+ * O processo principal já mostrava uma notificação do sistema, que some sozinha
+ * e passa despercebida se a pessoa não estiver olhando. Este aviso fica na
+ * janela até ser atendido ou dispensado.
+ */
+export function UpdateBanner() {
+  const t = useT();
+  const [version, setVersion] = useState<string | null>(null);
+  const [dismissed, setDismissed] = useState(false);
+
+  useEffect(() => {
+    if (!isElectron() || !window.backspace?.onUpdateDownloaded) return;
+    window.backspace.onUpdateDownloaded((info) => {
+      setVersion(info.version);
+      // Uma atualização nova reabre o aviso mesmo se a anterior foi dispensada:
+      // dispensar significa "agora não", não "nunca mais".
+      setDismissed(false);
+    });
+  }, []);
+
+  if (!version || dismissed) return null;
+
+  return (
+    <div className="fixed bottom-4 right-4 z-[400] max-w-[320px] glass rounded-xl shadow-xl p-3.5 animate-slide-up">
+      <div className="text-[13px] font-semibold text-txt-primary">{t('update.ready')}</div>
+      <p className="text-[12px] text-txt-secondary mt-0.5">
+        {t('update.readyVersion', { version })}
+      </p>
+      <div className="flex gap-2 mt-3">
+        <button
+          type="button"
+          onClick={() => window.backspace?.installUpdate?.()}
+          className="px-3 py-1.5 rounded-md text-[12px] font-medium bg-accent-primary text-white hover:brightness-110"
+        >
+          {t('update.restart')}
+        </button>
+        <button
+          type="button"
+          onClick={() => setDismissed(true)}
+          className="px-3 py-1.5 rounded-md text-[12px] font-medium bg-interactive-muted text-txt-secondary hover:text-txt-primary"
+        >
+          {t('update.later')}
+        </button>
+      </div>
+    </div>
+  );
+}

packages/web/src/i18n/locales/en.ts

@@ -56,6 +56,12 @@ export const en = {
   'accountMenu.copyId': 'Copy User ID',
   'accountMenu.copied': 'Copied',
 
+  // Desktop update
+  'update.ready': 'Update ready',
+  'update.readyVersion': 'Version {version} is ready to install.',
+  'update.restart': 'Restart to update',
+  'update.later': 'Later',
+
   // Custom emojis and stickers
   'expressions.title': 'Emojis & Stickers',
   'expressions.emojis': 'Emojis',

packages/web/src/i18n/locales/pt-BR.ts

@@ -55,6 +55,12 @@ export const ptBR: Partial<Dictionary> = {
   'accountMenu.copyId': 'Copiar ID do usuário',
   'accountMenu.copied': 'Copiado',
 
+  // Atualização do app
+  'update.ready': 'Atualização pronta',
+  'update.readyVersion': 'A versão {version} está pronta para instalar.',
+  'update.restart': 'Reiniciar para atualizar',
+  'update.later': 'Depois',
+
   // Emojis e figurinhas
   'expressions.title': 'Emojis e figurinhas',
   'expressions.emojis': 'Emojis',