468f34202a
The web terminal only hosts full-screen TUI tools (pi-agent, opencode), which repaint in place in the normal buffer and do not use the alternate screen or mouse tracking. With scrollback enabled, every repaint accumulated as history, so xterm's viewport scrollbar appeared and the mouse-wheel scrolled through stale frames instead of interacting with the app; the scrollbar column also perturbed FitAddon's column count. - terminal.tsx: set scrollback:0 and scrollSensitivity/fastScrollSensitivity:0 so only the live viewport is kept (no bar, no stale-frame wheel jank). - utilities.css: hide .xterm-viewport scrollbar (scrollbar-width:none + ::-webkit-scrollbar display:none) as belt-and-suspenders. Wheel no longer scrolls stale frames; in-app scrolling uses the tool's own keys. Headquarter-only change; no tool is touched.