feat(desktop): add Update now button to About panel

The About > Updates panel only surfaced "See what's new" when an update
was available, which just opens the changelog overlay — there was no way
to start the install directly from About. Add an "Update now" primary
button that opens the updates overlay (for apply progress) and kicks off
the install for the active target (backend in remote mode, else client).

apps/desktop/src/app/settings/about-settings.tsx

@@ -13,7 +13,8 @@ import {
   $updateStatus,
   checkUpdates,
   openUpdatesWindow,
-  refreshDesktopVersion
+  refreshDesktopVersion,
+  startActiveUpdate
 } from '@/store/updates'
 
 import { ListRow, SectionHeading, SettingsContent } from './primitives'
@@ -141,9 +142,14 @@ export function AboutSettings() {
             </Button>
 
             {behind > 0 && supported && !applying && (
-              <Button onClick={() => openUpdatesWindow()} size="sm">
-                {a.seeWhatsNew}
-              </Button>
+              <>
+                <Button onClick={() => startActiveUpdate()} size="sm">
+                  {a.updateNow}
+                </Button>
+                <Button onClick={() => openUpdatesWindow()} size="sm" variant="textStrong">
+                  {a.seeWhatsNew}
+                </Button>
+              </>
             )}
 
             <Button asChild className="ml-auto" size="sm" variant="text">

apps/desktop/src/i18n/en.ts

@@ -384,6 +384,7 @@ export const en: Translations = {
       checkNow: 'Check now',
       checking: 'Checking…',
       seeWhatsNew: "See what's new",
+      updateNow: 'Update now',
       releaseNotes: 'Release notes',
       onLatest: "You're on the latest version.",
       installing: 'An update is currently installing.',

apps/desktop/src/i18n/ja.ts

@@ -506,6 +506,7 @@ export const ja = defineLocale({
       checkNow: '今すぐ確認',
       checking: '確認中…',
       seeWhatsNew: '新機能を見る',
+      updateNow: '今すぐ更新',
       releaseNotes: 'リリースノート',
       onLatest: '最新バージョンです。',
       installing: '更新をインストール中です。',

apps/desktop/src/i18n/types.ts

@@ -281,6 +281,7 @@ export interface Translations {
       checkNow: string
       checking: string
       seeWhatsNew: string
+      updateNow: string
       releaseNotes: string
       onLatest: string
       installing: string

apps/desktop/src/i18n/zh-hant.ts

@@ -494,6 +494,7 @@ export const zhHant = defineLocale({
       checkNow: '立即檢查',
       checking: '檢查中…',
       seeWhatsNew: '查看新增內容',
+      updateNow: '立即更新',
       releaseNotes: '發行說明',
       onLatest: '你已是最新版本。',
       installing: '正在安裝更新。',

apps/desktop/src/i18n/zh.ts

@@ -582,6 +582,7 @@ export const zh: Translations = {
       checkNow: '立即检查',
       checking: '检查中…',
       seeWhatsNew: '查看新增内容',
+      updateNow: '立即更新',
       releaseNotes: '发行说明',
       onLatest: '你已是最新版本。',
       installing: '正在安装更新。',

apps/desktop/src/store/updates.ts

@@ -195,6 +195,20 @@ export function openUpdatesWindow(): void {
   openUpdateOverlayFor(isRemoteMode() ? 'backend' : 'client')
 }
 
+/**
+ * Start applying the available update for the active target right away. Opens
+ * the updates overlay first so the user sees apply progress (the overlay
+ * renders ApplyingView once `applying` flips true), then kicks off the install.
+ * Used by the "Update now" affordance on the About panel, which would otherwise
+ * only be able to open the changelog overlay.
+ */
+export function startActiveUpdate(): void {
+  const target: UpdateTarget = isRemoteMode() ? 'backend' : 'client'
+  $updateOverlayTarget.set(target)
+  $updateOverlayOpen.set(true)
+  void (target === 'backend' ? applyBackendUpdate() : applyUpdates())
+}
+
 /** Re-read the running app's version from the Electron main process and
  *  publish it on `$desktopVersion`. Called when the About panel mounts, the
  *  update flow finishes, and the window regains focus, so the About text