refactor: consolidate breadcrumbs to single TopBar instance

Remove duplicate in-page breadcrumbs (ExchangeDetail, AgentHealth scope
trail) and improve the global TopBar breadcrumb with semantic labels and
a context-based override for pages with richer navigation data.

- Add BreadcrumbProvider from design system v0.1.12
- LayoutShell: label map prettifies URL segments (apps→Applications, etc.)
- ExchangeDetail: uses useBreadcrumb() to set semantic trail via context
- AgentHealth: remove scope trail, keep live-count badge standalone

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ui/src/components/LayoutShell.tsx

@@ -1,5 +1,5 @@
 import { Outlet, useNavigate, useLocation } from 'react-router';
-import { AppShell, Sidebar, TopBar, CommandPalette, CommandPaletteProvider, GlobalFilterProvider, ToastProvider, useCommandPalette } from '@cameleer/design-system';
+import { AppShell, Sidebar, TopBar, CommandPalette, CommandPaletteProvider, GlobalFilterProvider, ToastProvider, BreadcrumbProvider, useCommandPalette } from '@cameleer/design-system';
 import type { SidebarApp, SearchResult } from '@cameleer/design-system';
 import { useRouteCatalog } from '../api/queries/catalog';
 import { useAgents } from '../api/queries/agents';
@@ -143,10 +143,23 @@ function LayoutContent() {
   }, [catalogData, exchangeResults]);
 
   const breadcrumb = useMemo(() => {
+    const LABELS: Record<string, string> = {
+      apps: 'Applications',
+      agents: 'Agents',
+      exchanges: 'Exchanges',
+      routes: 'Routes',
+      admin: 'Admin',
+      'api-docs': 'API Docs',
+      rbac: 'Users & Roles',
+      audit: 'Audit Log',
+      oidc: 'OIDC',
+      database: 'Database',
+      opensearch: 'OpenSearch',
+    };
     const parts = location.pathname.split('/').filter(Boolean);
     return parts.map((part, i) => ({
-      label: part,
-      href: '/' + parts.slice(0, i + 1).join('/'),
+      label: LABELS[part] ?? part,
+      ...(i < parts.length - 1 ? { href: '/' + parts.slice(0, i + 1).join('/') } : {}),
     }));
   }, [location.pathname]);
 
@@ -195,7 +208,9 @@ export function LayoutShell() {
     <ToastProvider>
       <CommandPaletteProvider>
         <GlobalFilterProvider>
-          <LayoutContent />
+          <BreadcrumbProvider>
+            <LayoutContent />
+          </BreadcrumbProvider>
         </GlobalFilterProvider>
       </CommandPaletteProvider>
     </ToastProvider>