feat: dashboard auto-refresh, collapsible sidebar, error retry

- Dashboard: auto-refresh toggle (30s interval, spins when live)
- Dashboard: responsive grid (6 cols mobile, 12 cols desktop)
- Sidebar: Dashboards, Saved views, Queues sections now collapsible
  with chevron toggle
- Error banner: added Retry button next to error message

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

web/src/app/page.tsx

@@ -864,8 +864,11 @@ function TicketWorkbenchContent() {
       </header>
 
       {error && (
-        <div className="shrink-0 border-b border-destructive/20 bg-destructive/10 px-5 py-2 text-sm text-destructive">
-          {error}
+        <div className="flex items-center justify-between shrink-0 border-b border-destructive/20 bg-destructive/10 px-5 py-2 text-sm text-destructive">
+          <span>{error}</span>
+          <button type="button" onClick={() => fetchData()} className="ml-3 text-xs font-medium underline hover:no-underline">
+            Retry
+          </button>
         </div>
       )}