feat(web): add smooth page transitions and WASM loading states

- Implement navigation state tracking with optimistic UI updates
- Add loading spinner and error handling for WASM initialization
- Insert browser yield points during game initialization to prevent freezing
- Redesign leaderboard with tabbed navigation and mock data structure
- Add utility CSS classes for consistent page layouts

web/package.json

@@ -9,7 +9,6 @@
   "name": "pacman-web",
   "description": "A web frontend for the Pac-Man game, including leaderboards and OAuth.",
   "dependencies": {
-    "@fontsource/nunito": "^5.2.7",
     "@fontsource/outfit": "^5.2.8",
     "@fontsource/pixelify-sans": "^5.2.7",
     "@fontsource/russo-one": "^5.2.7",
@@ -25,6 +24,7 @@
   "devDependencies": {
     "@eslint/js": "^9.35.0",
     "@tailwindcss/vite": "^4.1.13",
+    "@types/node": "^25.0.3",
     "@types/react": "^19.1.12",
     "@types/react-dom": "^19.1.9",
     "eslint": "^9.35.0",