feat(desktop/windows): show update-in-progress feedback before the desktop exits (#50419) (#50448)

Follow-up to #50238/#50381. The restart-loop is now SAFE (marker + launch
gate), but the trigger that lured users into relaunching mid-update remained:
on the in-app update hand-off the desktop window vanished almost immediately
(app.quit() 600ms after spawning the detached updater), before the updater's
own window appeared — a blank-screen gap that looks like a crash.

- Linger on the update overlay for UPDATE_HANDOFF_DWELL_MS (2.5s, was 600ms)
  before quitting, on BOTH hand-off paths (in-app update + Windows bootstrap
  recovery), so the message lands and bridges to the updater window.
- Strengthen the restart-stage copy and the overlay's applyingBody/applyingClose
  to explicitly tell the user the window will reopen automatically and NOT to
  reopen Hermes themselves while it updates. All four locales (en/ja/zh/zh-hant)
  updated in parity.

Pure UX; does not touch the #50381 marker/gate mutual-exclusion safety net.

apps/desktop/electron/main.cjs

@@ -1129,6 +1129,14 @@ function directoryExists(filePath) {
 // marker's own age ceiling; covers a stuck-but-alive updater).
 const UPDATE_WAIT_TIMEOUT_MS = 20 * 60 * 1000
 const UPDATE_WAIT_POLL_MS = 1000
+// How long the desktop lingers on the "updating, don't reopen" overlay after
+// spawning the detached updater, before it quits to release the venv shim. The
+// old 600ms was long enough to register the child process but far too short for
+// the user to READ the overlay — the window just vanished, looked like a crash,
+// and the user relaunched mid-update (the #50238 restart-loop trigger). A
+// couple of seconds lets the message land and bridges the gap until the
+// updater's own progress window appears. (#50419)
+const UPDATE_HANDOFF_DWELL_MS = 2500
 
 // Block until no live update is in progress (or we hit the wait timeout).
 // Emits a boot-progress phase so the renderer shows "Update in progress…"
@@ -1867,7 +1875,11 @@ async function applyUpdates(opts = {}) {
       return { ok: true, manual: true, command, hermesRoot: updateRoot }
     }
 
-    emitUpdateProgress({ stage: 'restart', message: 'Handing off to the Hermes updater…', percent: 100 })
+    emitUpdateProgress({
+      stage: 'restart',
+      message: 'Updating Hermes — this window will close and the updater will open. Don’t reopen Hermes yourself; it restarts automatically when the update finishes.',
+      percent: 100
+    })
     repairMacUpdaterHelper(updater)
 
     const updateRoot = resolveUpdateRoot()
@@ -1903,11 +1915,14 @@ async function applyUpdates(opts = {}) {
 
     rememberLog(`[updates] launched updater: ${updater} ${updaterArgs.join(' ')}; exiting desktop to release venv shim`)
 
-    // Give the OS a beat to register the new process, then quit. The updater
-    // rebuilds and relaunches us when it's done.
+    // Linger on the "updating — don't reopen" overlay long enough for the user
+    // to actually read it (and to bridge the gap until the updater's own window
+    // appears), THEN quit to release the venv shim. The updater rebuilds and
+    // relaunches us when it's done. (#50419 — a 600ms quit looked like a crash
+    // and lured users into the #50238 relaunch loop.)
     setTimeout(() => {
       app.quit()
-    }, 600)
+    }, UPDATE_HANDOFF_DWELL_MS)
 
     return { ok: true, handedOff: true, updater }
   } finally {
@@ -1946,9 +1961,12 @@ async function handOffWindowsBootstrapRecovery(reason) {
   child.unref()
 
   rememberLog(`[bootstrap] handed off ${reason} recovery to updater: ${updater} ${updaterArgs.join(' ')}; exiting desktop to release app.asar`)
+  // Same dwell as the in-app update hand-off (#50419): give the updater's
+  // window time to appear before we vanish, so the recovery doesn't look like
+  // a crash and provoke a mid-recovery relaunch.
   setTimeout(() => {
     app.quit()
-  }, 600)
+  }, UPDATE_HANDOFF_DWELL_MS)
 
   return true
 }

apps/desktop/src/i18n/en.ts

@@ -1382,10 +1382,11 @@ export const en: Translations = {
     copy: 'Copy',
     copied: 'Copied',
     done: 'Done',
-    applyingBody: 'The Hermes updater will take over in its own window and reopen Hermes when it’s done.',
+    applyingBody:
+      'The Hermes updater takes over in its own window and reopens Hermes automatically when it’s done. Please don’t reopen Hermes yourself while it’s updating.',
     applyingBodyBackend:
       'The remote backend is applying the update and will restart. Hermes reconnects automatically when it’s back.',
-    applyingClose: 'Hermes will close to apply the update.',
+    applyingClose: 'This window will close while the update runs, then Hermes reopens on its own.',
     errorTitle: 'Update didn’t finish',
     errorBody: 'No worries — nothing was lost. You can try again now.',
     notNow: 'Not now',

apps/desktop/src/i18n/ja.ts

@@ -1512,9 +1512,9 @@ export const ja = defineLocale({
     copy: 'コピー',
     copied: 'コピーしました',
     done: '完了',
-    applyingBody: 'Hermes アップデーターが独自のウィンドウで引き継ぎ、完了後に Hermes を再度開きます。',
+    applyingBody: 'Hermes アップデーターが独自のウィンドウで引き継ぎ、完了後に自動的に Hermes を再度開きます。更新中はご自分で Hermes を開き直さないでください。',
     applyingBodyBackend: 'リモートバックエンドが更新を適用して再起動します。復帰すると Hermes が自動的に再接続します。',
-    applyingClose: 'Hermes は更新を適用するために閉じます。',
+    applyingClose: 'このウィンドウは更新中に閉じ、その後 Hermes が自動的に再度開きます。',
     errorTitle: '更新が完了しませんでした',
     errorBody: 'ご安心ください。何も失われていません。今すぐ再試行できます。',
     notNow: '今は後で',

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

@@ -1463,9 +1463,9 @@ export const zhHant = defineLocale({
     copy: '複製',
     copied: '已複製',
     done: '完成',
-    applyingBody: 'Hermes 更新程式會在自己的視窗中接管，並在完成後重新開啟 Hermes。',
+    applyingBody: 'Hermes 更新程式會在自己的視窗中接管，並在完成後自動重新開啟 Hermes。更新期間請勿自行重新開啟 Hermes。',
     applyingBodyBackend: '遠端後端正在套用更新並將重新啟動。恢復後 Hermes 會自動重新連線。',
-    applyingClose: 'Hermes 將關閉以套用更新。',
+    applyingClose: '此視窗會在更新期間關閉，隨後 Hermes 會自動重新開啟。',
     errorTitle: '更新未完成',
     errorBody: '沒有資料遺失。您可以現在重試。',
     notNow: '暫不',

apps/desktop/src/i18n/zh.ts

@@ -1568,9 +1568,9 @@ export const zh: Translations = {
     copy: '复制',
     copied: '已复制',
     done: '完成',
-    applyingBody: 'Hermes 更新器会在自己的窗口中接管，并在完成后重新打开 Hermes。',
+    applyingBody: 'Hermes 更新器会在自己的窗口中接管，并在完成后自动重新打开 Hermes。更新期间请不要自行重新打开 Hermes。',
     applyingBodyBackend: '远程后端正在应用更新并将重启。恢复后 Hermes 会自动重新连接。',
-    applyingClose: 'Hermes 将关闭以应用更新。',
+    applyingClose: '此窗口会在更新期间关闭，随后 Hermes 会自动重新打开。',
     errorTitle: '更新未完成',
     errorBody: '没有数据丢失。你可以现在重试。',
     notNow: '暂不',