feat: migrate UI to @cameleer/design-system, add backend endpoints

Backend:
- Add agent_events table (V5) and lifecycle event recording
- Add route catalog endpoint (GET /routes/catalog)
- Add route metrics endpoint (GET /routes/metrics)
- Add agent events endpoint (GET /agents/events-log)
- Enrich AgentInstanceResponse with tps, errorRate, activeRoutes, uptimeSeconds
- Add TimescaleDB retention/compression policies (V6)

Frontend:
- Replace custom Mission Control UI with @cameleer/design-system components
- Rebuild all pages: Dashboard, ExchangeDetail, RoutesMetrics, AgentHealth,
  AgentInstance, RBAC, AuditLog, OIDC, DatabaseAdmin, OpenSearchAdmin, Swagger
- New LayoutShell with design system AppShell, Sidebar, TopBar, CommandPalette
- Consume design system from Gitea npm registry (@cameleer/design-system@0.0.1)
- Add .npmrc for scoped registry, update Dockerfile with REGISTRY_TOKEN arg

CI:
- Pass REGISTRY_TOKEN build-arg to UI Docker build step

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

ui/src/main.tsx

@@ -1,11 +1,11 @@
+import '@cameleer/design-system/style.css';
+import './index.css';
 import { StrictMode } from 'react';
 import { createRoot } from 'react-dom/client';
 import { RouterProvider } from 'react-router';
 import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
-import { ThemeProvider } from './theme/ThemeProvider';
+import { ThemeProvider } from '@cameleer/design-system';
 import { router } from './router';
-import './theme/fonts.css';
-import './theme/tokens.css';
 
 const queryClient = new QueryClient({
   defaultOptions: {