feat(web): leaderboard and replays pages with nav from landing

- Add leaderboard.html: JWT login form + localStorage token + table
- Add replays.html: public listing of recent replays, row click to viewer
- Wire /leaderboard and /replays routes in build_router_inner
- Fix home.html Recent Replays link from /api/replays/recent to /replays

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

solitaire_server/web/home.html

@@ -141,7 +141,7 @@
             </div>
         </a>
 
-        <a class="card" href="/api/replays/recent">
+        <a class="card" href="/replays">
             <div class="card-icon">&#9654;</div>
             <div class="card-body">
                 <div class="card-title">Recent Replays</div>