fix: prevent native text selection on mobile long-press

iOS triggered both the app context menu and native text selection overlay
on long-press. Three-layer fix: CSS user-select:none on buttons/[role=button]/
[data-context-menu] elements; non-passive touchstart listener with conditional
preventDefault on context-menu targets; removeAllRanges() at timer fire to
clear any residual selection. Added data-context-menu to all mobile surfaces
that use onContextMenu handlers.

packages/web/src/styles/globals.css

@@ -99,13 +99,18 @@
     text-rendering: optimizeLegibility;
   }
 
-  /* Suppress native long-press callout on mobile (iOS "Copy/Lookup" popup).
-     Our global useLongPress handler provides context menus instead.
+  /* Suppress native text selection and callout on mobile interactive elements.
+     Our global useGlobalLongPress handler provides context menus instead.
      Text can still be copied via context menu "Copy Text" option. */
   @media (max-width: 767px) {
     * {
       -webkit-touch-callout: none;
     }
+
+    button, [role="button"], [data-context-menu] {
+      -webkit-user-select: none;
+      user-select: none;
+    }
   }
 
   /* Thin scrollbar */