fix(lan-client): wire exit button to location.reload()

executeReset() references #game-board which doesn't exist in this HTML,
so the function threw a TypeError and silently did nothing. Swap the
exit button's onclick to location.reload() — the browser-refresh path
the user confirmed works to return to the setup screen.

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

lan-client/index.html

@@ -52,7 +52,7 @@
       <button class="btn-util" onclick="toggleSettingsPanel()" title="Settings">&#x2699;</button>
       <button class="btn-util" id="btn-search-toggle" onclick="document.getElementById('card-search-sidebar').classList.toggle('collapsed')" title="Card Search (S)">&#x1F50D;</button>
       <button class="btn-util" id="btn-deckbuilder-toggle" onclick="toggleDeckBuilderPanel()" title="Deck Builder">&#x1F0CF;</button>
-      <button class="btn-util btn-util-exit" onclick="confirmReset()" title="Return to Start Screen">&#x2715;</button>
+      <button class="btn-util btn-util-exit" onclick="location.reload()" title="Return to Start Screen">&#x2715;</button>
     </div>
 
     <!-- Storm counter -->