Add dd0c/route Dashboard UI: React + Vite + Tailwind SPA

- Layout with sidebar navigation (Dashboard, Rules, Keys, Settings)
- Dashboard page: stat cards, cost savings area chart (Recharts), model usage table
- Rules page: routing rules CRUD with modal editor, strategy/complexity/model matching
- Keys page: API key generation, copy-once reveal, revocation, quick-start code snippet
- Settings page: org info, provider config, danger zone
- API client (SWR + fetch wrapper) with full TypeScript types
- dd0c dark theme: indigo primary, cyan accent, dark surfaces
- Vite proxy config for local dev against API on :3000

products/01-llm-cost-router/ui/tsconfig.json

@@ -0,0 +1,22 @@
+{
+  "compilerOptions": {
+    "target": "ES2020",
+    "useDefineForClassFields": true,
+    "lib": ["ES2020", "DOM", "DOM.Iterable"],
+    "module": "ESNext",
+    "skipLibCheck": true,
+    "moduleResolution": "bundler",
+    "allowImportingTsExtensions": true,
+    "resolveJsonModule": true,
+    "isolatedModules": true,
+    "noEmit": true,
+    "jsx": "react-jsx",
+    "strict": true,
+    "noUnusedLocals": true,
+    "noUnusedParameters": true,
+    "noFallthroughCasesInSwitch": true,
+    "baseUrl": ".",
+    "paths": { "@/*": ["src/*"] }
+  },
+  "include": ["src"]
+}