fix: ensure watchlist interval is only created once

static/js/tabs.js

@@ -411,15 +411,17 @@ document.addEventListener('DOMContentLoaded', () => {
                                 displayWatchlist();
                             }
                             window.watchlistTabLoaded = true;
-                        }
                             
-                        // Start 30-second auto-refresh interval for watchlist
+                            // Start 30-second auto-refresh interval for watchlist (only once)
                             if (typeof displayWatchlist === 'function') {
                                 watchlistRefreshInterval = setInterval(() => {
                                     displayWatchlist();
                                 }, 30000);
                             }
                         }
+                        }
+                    }
+                    }
                 }, 100);
             };
         }