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/components/terminal.tsx

@@ -429,18 +429,73 @@ export const TerminalComponent = React.forwardRef<TerminalRef, TerminalProps>(
 			};
 			document.addEventListener("visibilitychange", handleVisibilityChange);
 
-			// Enable native touch scrolling on xterm.js viewport for mobile.
-			// xterm.js creates an internal .xterm-viewport div that has overflow-y
-			// scroll but may disable touch-action. We override it so the browser
-			// handles vertical touch panning natively.
-			if (isMobile) {
-				const viewport = container.querySelector(
-					".xterm-viewport",
-				) as HTMLElement | null;
-				if (viewport) {
-					viewport.style.touchAction = "pan-y";
-					viewport.style.overscrollBehavior = "contain";
+			// Mobile touch scroll forwarding.
+			// xterm.js intercepts touch events for selection, which blocks the
+			// browser from scrolling the viewport. We listen on the container in
+			// capture phase, decide early if the gesture is vertical, and then
+			// preventDefault + stopPropagation so xterm.js never sees the event.
+			// The scroll is forwarded to term.scrollLines().
+			let touchStartY = 0;
+			let touchStartX = 0;
+			let isVerticalScroll = false;
+			let accumulatedDeltaY = 0;
+
+			const handleTouchStart = (e: TouchEvent) => {
+				if (e.touches.length === 1) {
+					touchStartY = e.touches[0].clientY;
+					touchStartX = e.touches[0].clientX;
+					isVerticalScroll = false;
+					accumulatedDeltaY = 0;
 				}
+			};
+
+			const handleTouchMove = (e: TouchEvent) => {
+				if (e.touches.length !== 1 || !termRef.current) return;
+				const touch = e.touches[0];
+				const deltaY = touchStartY - touch.clientY;
+				const deltaX = Math.abs(touchStartX - touch.clientX);
+
+				// Decide scroll direction on the first meaningful movement (3px)
+				if (!isVerticalScroll) {
+					if (Math.abs(deltaY) > deltaX && Math.abs(deltaY) > 3) {
+						isVerticalScroll = true;
+					}
+				}
+
+				if (isVerticalScroll) {
+					// preventDefault MUST be called on the first matching touchmove
+					// or the browser compositor will already have committed to page
+					// scroll before our JS runs.
+					e.preventDefault();
+					e.stopPropagation();
+					accumulatedDeltaY += deltaY;
+					touchStartY = touch.clientY;
+					const lines = Math.round(accumulatedDeltaY / 24);
+					if (lines !== 0) {
+						// Negative = scroll up (show older buffer content)
+						termRef.current.scrollLines(-lines);
+						accumulatedDeltaY = 0;
+					}
+				}
+			};
+
+			const handleTouchEnd = () => {
+				isVerticalScroll = false;
+				accumulatedDeltaY = 0;
+			};
+
+			if (isMobile) {
+				container.addEventListener("touchstart", handleTouchStart, {
+					passive: true,
+					capture: true,
+				});
+				container.addEventListener("touchmove", handleTouchMove, {
+					passive: false,
+					capture: true,
+				});
+				container.addEventListener("touchend", handleTouchEnd, {
+					capture: true,
+				});
 			}
 
 			return () => {
@@ -454,6 +509,17 @@ export const TerminalComponent = React.forwardRef<TerminalRef, TerminalProps>(
 					"visibilitychange",
 					handleVisibilityChange,
 				);
+				if (isMobile) {
+					container.removeEventListener("touchstart", handleTouchStart, {
+						capture: true,
+					});
+					container.removeEventListener("touchmove", handleTouchMove, {
+						capture: true,
+					});
+					container.removeEventListener("touchend", handleTouchEnd, {
+						capture: true,
+					});
+				}
 				if (ws) {
 					ws.close(1000, "Component unmounting");
 				}

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>) => {

apps/web/src/styles.css

@@ -77,6 +77,10 @@ body {
 	color: var(--ink);
 }
 
+body.terminal-page-open {
+	overflow: hidden;
+}
+
 [data-theme="dark"] body {
 	background: radial-gradient(circle at top right, #2a2520, var(--bg));
 }
@@ -3709,14 +3713,6 @@ a.nav-item,
 
 /* xterm.js manages its own scrolling and viewport dimensions */
 
-/* Mobile: enable native touch scrolling on xterm viewport */
-.terminal-wrapper.mobile .xterm .xterm-viewport {
-	touch-action: pan-y !important;
-	-webkit-overflow-scrolling: touch !important;
-	overflow-y: auto !important;
-	scrollbar-width: none;
-}
-
 /* Special Keys Strip */
 .special-keys-strip {
 	flex-shrink: 0;