fix(ui): refresh button triggers full reload and update restart auto-recovers (#168)

SessionsHub refresh button now clears caches and does a full page reload
(matching the CommandPalette refresh). This also naturally re-triggers
the update check on mount.

UpdateBanner polling now detects when the server bounces during a
restart — tracks the server going down (null responses), then reloads
the page when it comes back. Previously the UI got stuck on
'Restarting...' because the restarted server returned status: idle which
had no handler.

Closes #167

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: dorlugasigal

src/frontend/src/components/SessionsHub/SessionsHub.tsx

@@ -119,8 +119,14 @@ export default function SessionsHub() {
 
   async function handleRefresh() {
     setRefreshing(true);
-    await loadSessions();
-    setTimeout(() => setRefreshing(false), 600);
+    try {
+      if ('caches' in window && typeof window.caches?.keys === 'function') {
+        const cacheNames = await caches.keys();
+        await Promise.all(cacheNames.map((name) => caches.delete(name)));
+      }
+    } finally {
+      location.reload();
+    }
   }
 
   function handleShare() {

src/frontend/src/components/common/UpdateBanner.tsx

@@ -54,6 +54,7 @@ export default function UpdateBanner() {
   const commandRef = useRef('');
   const pollRef = useRef<ReturnType<typeof setInterval> | null>(null);
   const copiedTimerRef = useRef<ReturnType<typeof setTimeout> | null>(null);
+  const sawServerDownRef = useRef(false);
 
   // Clean up copied timer on unmount
   useEffect(() => {
@@ -122,8 +123,24 @@ export default function UpdateBanner() {
   useEffect(() => {
     const isUpdating = state.kind === 'updating' || state.kind === 'restarting';
     if (isUpdating && !pollRef.current) {
+      // Reset server-down tracking when entering restarting state
+      if (state.kind === 'restarting') sawServerDownRef.current = false;
       pollRef.current = setInterval(async () => {
         const status = await getUpdateStatus();
+
+        // Detect server bounce during restart: server down → server back → reload
+        if (state.kind === 'restarting') {
+          if (!status) {
+            sawServerDownRef.current = true;
+            return;
+          }
+          if (sawServerDownRef.current || status.status === 'idle') {
+            // Server came back after restart — reload to pick up new assets
+            window.location.reload();
+            return;
+          }
+        }
+
         if (!status) return;
         if (status.status === 'complete') {
           setState({ kind: 'success', toVersion: status.toVersion || '?' });