feat: hide IP addresses by default, click to reveal

Added maskIp() helper that replaces IPs with ••••••••. A global
delegated click handler reveals the address on click. Applied to:
- Player list 'Address' column
- Player info 'Address' field

Styled .ip-masked with dimmed text and purple hover glow.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

js/app.js

@@ -109,6 +109,23 @@
 
   Router.start('#app-view');
 
+  // ---- IP address masking ----
+  window.maskIp = function (ip) {
+    if (!ip) return '';
+    return '<span class="ip-masked" data-ip="' + ip + '" title="Click to reveal IP">••••••••</span>';
+  };
+
+  document.addEventListener('click', function (e) {
+    var el = e.target.closest('.ip-masked');
+    if (el) {
+      el.classList.remove('ip-masked');
+      el.classList.add('ip-revealed');
+      el.textContent = el.dataset.ip;
+      el.title = '';
+      e.preventDefault();
+    }
+  });
+
   // ---- Initial state ----
   showDisconnected();
 })();