refactor: frontend de-spaghetti (dup declares, dead code, log gating)

- Remove the duplicate _gameMode declaration in the client SocketHandlers
  object literal — it was declared twice, so the later `null` silently
  shadowed the earlier `'free'`. Now declared once with the effective value.
- Remove the dead SocketHandlers._appendMessage calls in smirkAuth.js; that
  method never existed, so the guard always fell through to the working
  .text() append. Keep the safe append.
- Gate broadcastManager's high-volume per-event logs (user count, chat message
  incl. message/socketId PII, game update, game start) behind debug mode;
  previously they logged on every event regardless of NODE_ENV.

Full suite: 21 suites / 155 tests.

html/js/network/smirkAuth.js

@@ -214,11 +214,8 @@ const SmirkAuth = {
                 ? 'Smirk wallet connected! Payout address set.'
                 : 'Smirk wallet authenticated! Please set your payout address manually.';
 
-            if (typeof SocketHandlers !== 'undefined' && SocketHandlers._appendMessage) {
-                SocketHandlers._appendMessage('status', successMsg);
-            } else {
-                $('#messages').append($('<li class="status">').text(successMsg));
-            }
+            // .text() sets textContent, so the message is safe from injection.
+            $('#messages').append($('<li class="status">').text(successMsg));
 
             // Update address button status if available
             if (typeof SocketHandlers !== 'undefined' && SocketHandlers._updateAddressButtonStatus) {
@@ -233,11 +230,7 @@ const SmirkAuth = {
 
             // Show error message
             const errorMsg = 'Smirk login failed: ' + err.message;
-            if (typeof SocketHandlers !== 'undefined' && SocketHandlers._appendMessage) {
-                SocketHandlers._appendMessage('error', errorMsg);
-            } else {
-                $('#messages').append($('<li class="error">').text(errorMsg));
-            }
+            $('#messages').append($('<li class="error">').text(errorMsg));
 
             throw err;
         }

html/js/network/socketHandlers.js

@@ -13,7 +13,8 @@ const SocketHandlers = {
 
     _hasPayoutAddress: false,
     _creditsBalance: 0,
-    _gameMode: 'free',
+    _gameMode: null, // set from the server's game-modes event; was previously declared
+                     // twice in this object literal (the later `null` silently won)
 
     _directPayoutsEnabled: false,
     _paymentsEnabled: false,
@@ -1394,8 +1395,7 @@ const SocketHandlers = {
     // =====================
     // Early Entry Functions
     // =====================
-    
-    _gameMode: null,
+
     _earlyEntryConfig: { enabled: false },
     _isQueued: false,