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/static/terminal.js

@@ -10,8 +10,6 @@
   const touch = matchMedia('(pointer: coarse)').matches;
   const desk = !touch; // drag and drop, splits: computers only
   if (touch) document.body.classList.add('touch');
-  const ua = (navigator.userAgentData && navigator.userAgentData.platform) || navigator.platform || navigator.userAgent;
-  if (/^Win/i.test(ua) || /Windows/.test(navigator.userAgent)) document.body.classList.add('win');
   const $ = id => document.getElementById(id);
   const statusEl = $('status'), area = $('area'), tablist = $('tablist'), addBtn = $('tabadd'),
     floatAdd = $('floatadd'), addMenu = $('addmenu'), hint = $('hint'), mark = $('tabmark');