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/settings.html

@@ -6,6 +6,7 @@
 <title>Настройки - LPRA</title>
 <link rel="stylesheet" href="{{asset "app.css"}}">
 <script src="{{asset "pin.js"}}"></script>
+<script src="{{asset "scroll.js"}}" defer></script>
 <style>
   /* An install command, with a button to copy it at its right. */
   /* Users: role, machines, password sign-in. */