Have the refresh button check for a new build too

The version poller already diffs /api/version against the manifest
captured at boot -- hot-swapping changed CSS, reloading for changed
JS/HTML once playback allows -- but only on its own 60s tick or when the
tab regains visibility. Pressing refresh now runs that same check in the
background, so a tab left open across a deploy picks the new build up
when the user asks for fresh content rather than up to a minute later.
App.version.checkNow() exposes it; with no baseline (the endpoint was
down at boot) it just adopts the current manifest, since there is nothing
to compare against yet.

Verified against the running app: appending to style.css and pressing
refresh swapped the tag to style.css?v=<hash> with the page still alive,
and appending to a .js file reloaded the page.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QBDkEXP4htyXTCZUwMLphd

frontend/js/ui.js

@@ -461,6 +461,13 @@ App.ui = App.ui || {};
 
         if (reloadChannelBtn) {
             reloadChannelBtn.onclick = () => {
+                // Refresh means "give me the current everything": the videos
+                // below, and the app itself. The version check runs in the
+                // background and only acts if the deployed assets actually
+                // differ from what this tab is running.
+                if (App.version && typeof App.version.checkNow === 'function') {
+                    App.version.checkNow();
+                }
                 App.videos.resetAndReload();
             };
         }

frontend/js/version.js

@@ -114,6 +114,21 @@ App.version = App.version || {};
         }
     }
 
+    // Same check the poller runs, on demand: the top-bar refresh button asks for
+    // it so a tab left open across a deploy picks the new build up right then,
+    // rather than up to POLL_INTERVAL_MS later. Changed CSS hot-swaps; changed
+    // JS/HTML reloads as soon as that won't interrupt playback.
+    App.version.checkNow = function() {
+        if (!baseline) {
+            // start() never got a manifest (endpoint down, or it hasn't run
+            // yet). Adopt whatever the server reports now so there's something
+            // to diff against next time -- there's no baseline to compare this
+            // one against, so nothing can be concluded from it today.
+            return fetchVersion().then((latest) => { baseline = latest; }).catch(() => {});
+        }
+        return check();
+    };
+
     App.version.start = async function() {
         try {
             baseline = await fetchVersion();