Dashboard Studio 1.6.1: show version, load fresh files after updates

- Version shown under About in the dashboard settings, with a link to
  the repository; /api/version reports it
- index.html is never cached and stamps the version on every asset URL,
  so browsers can't keep running old files after an update
- Open screens check the version after reconnecting and every 5 minutes
  and reload into the new version (editing only shows a message);
  pending saves are flushed first

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

dashboard_studio/web/style.css

@@ -439,6 +439,8 @@ body.kiosk #tabnav { top: 6px; max-height: calc(100vh - 20px); }
 }
 .surface-plain #tabnav { background: transparent; border-color: transparent; backdrop-filter: none; -webkit-backdrop-filter: none; }
 .i.flip { transform: rotate(180deg); }
+.about { display: flex; align-items: center; gap: 12px; }
+.about img { border-radius: 10px; flex: none; }
 .tab-list { display: flex; flex-direction: column; gap: 6px; margin-bottom: 4px; }
 .tab-item { display: flex; gap: 4px; align-items: center; }
 .tab-item .input { min-width: 0; }