phase5: workspace frontend — API hooks, useWorkspace hook, WorkspaceSwitcher, Sidebar workspace filter

frontend/src/components/layout/TopBar.tsx

@@ -10,6 +10,7 @@ import { SearchDropdown } from '@/components/shared/SearchDropdown';
 import { SuggestionBadge } from '@/components/ai/SuggestionBadge';
 import { Building, ChevronDown, Menu, Zap, Bot, Layers, Code } from 'lucide-react';
 import { NotificationBell } from '@/components/layout/NotificationBell';
+import { WorkspaceSwitcher } from '@/components/layout/WorkspaceSwitcher';
 import { useWindowStore } from '@/store/windowStore';
 import { usePermission } from '@/hooks/usePermission';
 
@@ -87,6 +88,7 @@ export function TopBar() {
       </div>
 
       <div className="flex items-center gap-2">
+        <WorkspaceSwitcher />
         <NotificationBell />
         {/* Minimized windows */}
         {minimizedWindows.length > 0 && (