fix: suppress native iOS callout on mobile long-press

Add -webkit-touch-callout: none on mobile viewports to prevent the
native iOS copy/lookup popup from racing with our context menu.
Clear any text selection when the long-press timer fires.

packages/web/src/components/ui/ContextMenuRenderer.tsx

@@ -560,6 +560,8 @@ function useGlobalLongPress(isMobile: boolean) {
       timer = setTimeout(() => {
         timer = null;
         fired = true;
+        // Clear any native text selection that started during the hold
+        window.getSelection()?.removeAllRanges();
         // Dispatch synthetic contextmenu on the original target.
         // React's event delegation picks it up and fires onContextMenu handlers.
         const syntheticEvent = new MouseEvent('contextmenu', {

packages/web/src/styles/globals.css

@@ -99,6 +99,15 @@
     text-rendering: optimizeLegibility;
   }
 
+  /* Suppress native long-press callout on mobile (iOS "Copy/Lookup" popup).
+     Our global useLongPress handler provides context menus instead.
+     Text can still be copied via context menu "Copy Text" option. */
+  @media (max-width: 767px) {
+    * {
+      -webkit-touch-callout: none;
+    }
+  }
+
   /* Thin scrollbar */
   ::-webkit-scrollbar {
     width: 8px;