fix(1.0.5): revert Sec-CH-UA spoof (white pages), add DevTools shortcut

- Sec-CH-UA / Sec-CH-UA-Mobile / Sec-CH-UA-Platform header overrides on
  every request in 1.0.4 broke page rendering (all views white). Reverted
  to image-Referer-only behavior from 1.0.3. The Google "embedded browser"
  fix in 1.0.4 came primarily from the adblock whitelist (which IS kept)
  — Sec-CH-UA spoofing was the suspect for the regression.
- Ctrl+Shift+I and F12 now open DevTools on the main shell and on every
  in-app browser view. Always-on so kiosk machines can be debugged
  without leaving kiosk mode.
- Restore session sequenced (await 150ms between tabs) to avoid concurrent
  create-view races where multiple setLoader/addChild interleaved.
- Update banner now shows error state with a "Повторить" button instead
  of hiding it, so install-update failures are visible to the user.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/components/Header.tsx

@@ -290,14 +290,22 @@ const Header: React.FC<HeaderProps> = ({ activeApp, setActiveApp, onAppsChange,
         )}
       </div>
 
-      {updateStatus && updateStatus.state !== 'error' && (
-        <div className="update-banner">
+      {updateStatus && (
+        <div className={`update-banner${updateStatus.state === 'error' ? ' error' : ''}`}>
           {updateStatus.state === 'available' && (
             <>
               <span className="update-banner-spinner" />
               <span>Загружается обновление {updateStatus.version}{updateStatus.currentVersion ? ` (текущая ${updateStatus.currentVersion})` : ''}…</span>
             </>
           )}
+          {updateStatus.state === 'error' && (
+            <>
+              <span>Ошибка обновления: {updateStatus.message}</span>
+              <button className="update-banner-btn" onClick={() => window.electron?.checkUpdateNow?.()}>
+                Повторить
+              </button>
+            </>
+          )}
           {updateStatus.state === 'downloading' && (
             <>
               <span>Скачивается {updateStatus.version || 'обновление'}: {updateStatus.percent}%</span>