fix(auth): only reset activeTab on mount, don't block tab switching

Previous code continuously forced activeTab to 'messages' when not
authenticated, making dashboard and voice tabs unclickable.
Now uses useEffect once on mount to reset localStorage carryover,
then lets tab switching work normally.

services/frontend/src/App.tsx

@@ -41,7 +41,17 @@ export default function App() {
 
   const audio = useAudioPlayback();
   const isPublicDashboard = import.meta.env.VITE_DASHBOARD_IS_PUBLIC === "true";
-  const activeTab = !authenticated && !isPublicDashboard ? "messages" : uiState.activeTab || "messages";
+  const activeTab = uiState.activeTab || "messages";
+
+  // Reset persisted tab to "messages" once on mount if not authenticated
+  // Prevents localStorage carryover from a prior session on the Live tab
+  useEffect(() => {
+    if (!authenticated && !isPublicDashboard && uiState.activeTab === "live") {
+      patchUIState({ activeTab: "messages" });
+    }
+    // Run only on mount
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, []);
   const selectedVoiceGuild =
     uiState.selectedVoiceGuild || uiState.selectedGuild || "";