Rework the chess page into a chess.com-style layout

Board with player bars and captured trays on the left, a game panel with
move list, status, and action buttons on the right. The page is locked to
the viewport (no scrolling); on phones the panel collapses into a slide-up
menu reachable from a slim status bar. Cache-busts the chess scripts too.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

JoshHeaps.Net/Pages/_Layout.cshtml

@@ -1,6 +1,6 @@
 @{
     Layout = null;
-    ViewData["cssVersion"] = "1.0.5"; // <--- change this once to bust cache
+    ViewData["cssVersion"] = "1.0.7"; // <--- change this once to bust cache
 }
 
 <!DOCTYPE html>