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/Dockerfile

@@ -1,8 +1,11 @@
 FROM --platform=$BUILDPLATFORM node:22-alpine AS build
 WORKDIR /app
 
-COPY package.json package-lock.json ./
-RUN npm ci
+ARG REGISTRY_TOKEN
+COPY package.json package-lock.json .npmrc ./
+RUN echo "//gitea.siegeln.net/api/packages/cameleer/npm/:_authToken=${REGISTRY_TOKEN}" >> .npmrc && \
+    npm ci && \
+    rm -f .npmrc
 
 COPY . .