Fix Android updates dialog, mobile About page, and user color crash guard.

Use stripBase for update static copy paths, show Settings detail on mobile
when nav is hidden, pause Settings focus trap during release notes, and guard
extractMemberColorPreference when room is not a Matrix Room instance.

index.html

@@ -96,6 +96,12 @@
     </script>
     <div id="root"></div>
     <div id="portalContainer"></div>
+    <style>
+      #portalContainer {
+        position: relative;
+        z-index: 10000;
+      }
+    </style>
     <script type="module" src="./src/index.tsx"></script>
   </body>
 </html>