fix: route mobile terminal swipes to the terminal, not the page layout

- Add touch-action: none and overscroll-behavior: none to mobile terminal
  page, content, wrapper, container, and xterm viewport so the browser
  never treats swipes as page/address-bar scrolling or pull-to-refresh.
- Make .terminal-page.mobile fixed-position to prevent viewport layout
  scroll; keep the overlay toolbar as absolute with pointer-events only
  on interactive parts.
- Rework the mobile touch handler in terminal.tsx:
  * Detect normal vs alternate buffer via term.buffer.active.type instead
    of measuring the DOM viewport, which was unreliable in tmux/vim.
  * Accumulate swipe distance and emit SGR 1006 mouse-wheel sequences in
    steps, so tmux pane scrolling tracks the gesture correctly.
  * Prevent default as soon as the swipe is recognized so the page does
    not start a competing scroll gesture.

Quality gates: npm run typecheck, npm run lint clean, npm test -- --run 87 passed.

apps/web/src/styles/utilities.css

@@ -551,6 +551,14 @@ a.nav-item,
 	height: 100%;
 	padding: 0;
 	overflow: hidden;
+	touch-action: none;
+	overscroll-behavior: none;
+}
+
+/* Ensure xterm's internal viewport also disables browser gestures on mobile */
+.terminal-container .xterm-viewport {
+	touch-action: none;
+	overscroll-behavior: none;
 }
 
 /* xterm.js manages its own positioning and sizing */
@@ -564,6 +572,13 @@ a.nav-item,
 /* Mobile terminal container - no padding to maximize space */
 .terminal-wrapper.mobile .terminal-container {
 	padding: 0;
+	touch-action: none;
+	overscroll-behavior: none;
+}
+
+.terminal-wrapper.mobile {
+	touch-action: none;
+	overscroll-behavior: none;
 }
 
 /* Ensure xterm viewport fills container properly */
@@ -855,17 +870,23 @@ a.nav-item,
    Mobile Terminal Overlay
    ============================================ */
 
-/* Mobile terminal page — no padding, terminal fills viewport */
+/* Mobile terminal page — no padding, terminal fills viewport, locked in place */
 .terminal-page.mobile {
 	padding: 0;
 	gap: 0;
 	height: 100vh;
 	height: 100dvh;
-	position: relative;
+	position: fixed;
+	top: 0;
+	left: 0;
+	right: 0;
+	bottom: 0;
 	overflow: hidden;
+	touch-action: none;
+	overscroll-behavior: none;
 }
 
-/* Overlay status bar — floats over terminal, never resizes it */
+/* Overlay status bar — floats over terminal; only its buttons consume pointer events */
 .mobile-terminal-overlay {
 	position: absolute;
 	top: 0;
@@ -874,11 +895,21 @@ a.nav-item,
 	z-index: 100;
 	background: #2d2d2d;
 	border-bottom: 1px solid #3e3e3e;
+	pointer-events: none;
 	transition:
 		transform 0.3s ease,
 		opacity 0.3s ease;
 }
 
+.mobile-terminal-overlay.visible {
+	pointer-events: auto;
+}
+
+.mobile-terminal-overlay > *,
+.mobile-terminal-overlay-tabs {
+	pointer-events: auto;
+}
+
 .mobile-terminal-overlay.hidden {
 	transform: translateY(-100%);
 	opacity: 0;
@@ -978,13 +1009,15 @@ a.nav-item,
 	border-bottom: none;
 }
 
-/* Terminal content — always fills full viewport on mobile */
+/* Terminal content — always fills full viewport on mobile, locked against page scroll */
 .terminal-page-content.mobile-full {
 	flex: 1;
 	min-height: 0;
 	border: none;
 	border-radius: 0;
 	overflow: hidden;
+	touch-action: none;
+	overscroll-behavior: none;
 }
 
 /* Mobile fullscreen */