feat(updater): fixed-URL auto-update channel + silent retries

The auto-update system used a per-version publish URL
(releases/download/v${version}), so each installed build only ever
checked its own release page for new versions. To deliver an update we
had to manually copy the new manifest into every old release — easy to
forget, and any half-uploaded state showed users red "check failed"
banners.

Architectural fix:

- New rolling 'update-channel' Gitea release. publish.url is now a
  fixed path (.../releases/download/update-channel) that never moves.
- release.ps1 uploads each new build to three places:
    1. vX.Y.Z          (historical archive + changelog)
    2. update-channel  (what every client polls)
    3. -BridgeTags     (transition: also fill in old releases so users
                       still on those versions can find the new build)
- upload-release-assets.ps1 gains -AssetVersion to upload version-X.Y.Z
  artifacts into a non-version tag (channel/bridge).

Resilience fixes for the updater itself:

- Hourly checks and the boot check now run in SILENT mode: network
  errors don't promote to a red error state, they're logged and
  retried on the next tick. Only user-initiated "Check now" surfaces
  errors. This prevents the cascade of "Ошибка проверки" cards on
  flaky networks or partial uploads.
- Boot check retries up to 3 times (30s/2m/5m backoff) before giving
  up until the hourly tick.
- Track lastCheckedAt; "Up to date" subtitle now shows "checked Nm ago".

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/renderer/src/components/UpdaterCard.tsx

@@ -10,9 +10,18 @@ import {
 import { motion } from 'framer-motion'
 import { Button } from './ui/Button'
 import { Card } from './ui/Card'
-import { useT } from '../i18n'
+import { useT, type TFn } from '../i18n'
 import type { UpdaterStatus } from '@shared/types'
 
+function formatChecked(ts: number, t: TFn): string {
+  const diffMs = Date.now() - ts
+  const diffMin = Math.max(0, Math.round(diffMs / 60_000))
+  if (diffMin < 1) return t('updater.checked.just_now')
+  if (diffMin < 60) return t('updater.checked.minutes_ago', { n: diffMin })
+  const diffH = Math.round(diffMin / 60)
+  return t('updater.checked.hours_ago', { n: diffH })
+}
+
 export function UpdaterCard(): JSX.Element {
   const [status, setStatus] = useState<UpdaterStatus>({ kind: 'idle' })
   const [busy, setBusy] = useState(false)
@@ -96,12 +105,18 @@ function Body({
     )
   }
   if (status.kind === 'not-available') {
+    const subtitle = status.lastCheckedAt
+      ? t('updater.up_to_date.subtitle_checked', {
+          v: status.currentVersion,
+          when: formatChecked(status.lastCheckedAt, t)
+        })
+      : t('updater.up_to_date.subtitle', { v: status.currentVersion })
     return (
       <Cell
         tone="success"
         icon={<CheckCircle2 size={16} strokeWidth={2.4} />}
         title={t('updater.up_to_date')}
-        subtitle={t('updater.up_to_date.subtitle', { v: status.currentVersion })}
+        subtitle={subtitle}
         action={
           <Button variant="tinted" size="sm" onClick={onCheck} disabled={busy}>
             <RefreshCw size={13} strokeWidth={2.5} /> {t('btn.check')}

src/renderer/src/i18n/dict.ts

@@ -185,6 +185,11 @@ export const ru: Dict = {
   'updater.checking': 'Проверяем обновления…',
   'updater.up_to_date': 'Последняя версия',
   'updater.up_to_date.subtitle': 'Текущая: v{v}',
+  'updater.up_to_date.subtitle_checked': 'Текущая: v{v} · проверено {when}',
+  'updater.last_checked': 'проверено {when}',
+  'updater.checked.just_now': 'только что',
+  'updater.checked.minutes_ago': '{n} мин назад',
+  'updater.checked.hours_ago': '{n} ч назад',
   'updater.available.title': 'Доступна v{v}',
   'updater.downloading.title': 'Загружаем обновление',
   'updater.downloading.subtitle': '{got} / {total} МБ · {speed} МБ/с',
@@ -398,6 +403,11 @@ export const en: Dict = {
   'updater.checking': 'Checking for updates…',
   'updater.up_to_date': 'Up to date',
   'updater.up_to_date.subtitle': 'Current: v{v}',
+  'updater.up_to_date.subtitle_checked': 'Current: v{v} · checked {when}',
+  'updater.last_checked': 'checked {when}',
+  'updater.checked.just_now': 'just now',
+  'updater.checked.minutes_ago': '{n}m ago',
+  'updater.checked.hours_ago': '{n}h ago',
   'updater.available.title': 'v{v} available',
   'updater.downloading.title': 'Downloading update',
   'updater.downloading.subtitle': '{got} / {total} MB · {speed} MB/s',

src/renderer/src/i18n/index.ts

@@ -9,6 +9,7 @@ export function getDict(lang: Language): Dict {
 }
 
 export type TVars = Record<string, string | number>
+export type TFn = (key: string, vars?: TVars) => string
 
 /**
  * Look up a key in the dictionary, substitute `{var}` placeholders.