Sync React frontend into git

- Replace stale TanStack Router scaffold with working react-router-dom app
- Add all 9 page components + cyber theme CSS
- Remove routeTree.gen.ts, add index.css, query.ts

frontend/package.json

@@ -12,7 +12,8 @@
     "@tanstack/react-query": "^5.62.0",
     "@tanstack/react-router": "^1.100.0",
     "react": "^18.3.1",
-    "react-dom": "^18.3.1"
+    "react-dom": "^18.3.1",
+    "react-router-dom": "^7.18.2"
   },
   "devDependencies": {
     "@types/react": "^18.3.18",