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/pages/+onPageTransitionEnd.ts

@@ -1,10 +1,10 @@
 import type { OnPageTransitionEndAsync } from "vike/types";
 import { getPacmanWindow } from "@/lib/pacman";
+import { setPendingNavigation } from "@/lib/navigation";
 
-export const onPageTransitionEnd: OnPageTransitionEndAsync = async (
-  pageContext
-) => {
+export const onPageTransitionEnd: OnPageTransitionEndAsync = async (pageContext) => {
   console.log("Page transition end");
+  setPendingNavigation(null);
   document.querySelector("body")?.classList.remove("page-is-transitioning");
 
   // Restart the game loop when returning to the game page