Add simple WebSocket multiplayer

index.html

@@ -24,6 +24,8 @@
           <div id="message" class="message">Trap enemy marks between your marks. First to four wins.</div>
         </div>
 
+        <div id="networkStatus" class="network-status connecting" role="status">Connecting to matchmaker...</div>
+
         <div id="board" class="board" role="grid" aria-label="Tictactics board"></div>
       </section>
 
@@ -41,7 +43,7 @@
 
         <div class="rule-card">
           <h2>Rule</h2>
-          <p>Place a mark on an empty cell. Any enemy marks trapped in a straight line between your marks are removed.</p>
+          <p>Open the game in two browser windows. The first two connected players are paired automatically.</p>
         </div>
 
         <ol id="moveList" class="move-list" aria-label="Move history"></ol>
@@ -51,4 +53,3 @@
     <script src="game.js"></script>
   </body>
 </html>
-