fix: lock body scroll and re-add programmatic terminal touch scroll

- Add body.terminal-page-open { overflow: hidden } to prevent page scroll
- TerminalPage adds/removes 'terminal-page-open' class on body when mounted
- Re-add capture-phase touch listeners in terminal.tsx with low 3px threshold
- Call e.preventDefault() immediately when vertical gesture is detected,
  before browser compositor commits to page scroll
- Remove CSS touch-action overrides on xterm viewport (now handled in JS)
- Scroll forwarded via term.scrollLines() with 24px per line sensitivity

apps/web/src/pages/terminal.tsx

@@ -204,6 +204,16 @@ export const TerminalPage: React.FC = () => {
 		};
 	}, []);
 
+	// Lock body scroll on mobile terminal so swipes scroll the terminal buffer,
+	// not the page.
+	useEffect(() => {
+		if (!isMobile) return;
+		document.body.classList.add("terminal-page-open");
+		return () => {
+			document.body.classList.remove("terminal-page-open");
+		};
+	}, [isMobile]);
+
 	// Click outside terminal content/header to exit fullscreen
 	const handleFullscreenClick = useCallback(
 		(e: React.MouseEvent<HTMLElement>) => {