Hide companion features on mobile

assets/companion.js

@@ -186,7 +186,19 @@
         });
     }
 
+    function isMobileDevice() {
+        // The companion only ships for Windows and Linux desktops, so skip it
+        // on phones/tablets. Checks the UA and falls back to "touch is the only
+        // pointer" so narrow desktop windows still get the companion.
+        if (/Android|iPhone|iPad|iPod|Mobi/i.test(navigator.userAgent)) return true;
+        return window.matchMedia('(pointer: coarse)').matches &&
+            !window.matchMedia('(any-pointer: fine)').matches;
+    }
+
     function init() {
+        // Every companion element is rendered hidden, so bailing out here
+        // leaves the status icon and reveal buttons invisible on mobile.
+        if (isMobileDevice()) return;
         probeStatus().then(function () {
             updateFooterIcon();
             wireFileLinks();