feat: Mac-like scrollbars - thin, no track, shown while scrolling or at the edge and fading out, none when there is nothing to scroll; a lone terminal's bar sits by the frame, right of the plus

internal/server/web/templates/status.html

@@ -6,6 +6,7 @@
 <title>Статус · {{.Agent.Name}} - LPRA</title>
 <link rel="stylesheet" href="{{asset "app.css"}}">
 <script src="{{asset "pin.js"}}"></script>
+<script src="{{asset "scroll.js"}}" defer></script>
 <style>
   .meters { display:grid; grid-template-columns:repeat(auto-fit, minmax(240px, 1fr)); gap:20px; margin-bottom:20px; }
   .meters .card { margin:0; }