feat(dashboard): React frontend scaffold with overview page

- Vite + React 18 + TypeScript + Tailwind CSS
- Dashboard overview with health gauge, pillar bars, alerts
- WebSocket hook for real-time updates
- Layout with sidebar navigation and live indicator
- Placeholder pages for Mesh, Environment, Config, Alerts
- Dark theme ops center aesthetic with JetBrains Mono

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

dashboard-frontend/tsconfig.node.json

@@ -0,0 +1,11 @@
+{
+  "compilerOptions": {
+    "composite": true,
+    "skipLibCheck": true,
+    "module": "ESNext",
+    "moduleResolution": "bundler",
+    "allowSyntheticDefaultImports": true,
+    "strict": true
+  },
+  "include": ["vite.config.ts"]
+}