fix(welcome): rotate startup tips (#5871)

static/index.html

@@ -1005,7 +1005,7 @@
       var tips = mobile ? phone : desktop;
       var el = document.getElementById('welcome-tip');
       if (el) {
-        el.textContent = 'Pick a model if you want, or just type.';
+        el.textContent = tips[Math.floor(Math.random() * tips.length)];
       }
       fetch('/api/version').then(function(r){return r.json()}).then(function(d){
         if (d.version) window._appVersion = d.version;