fix(visualizer): sync state and re-subscribe from audio device load

- Broaden audio import errors from ImportError to Exception, log at warning
- Move visualizer WS re-subscription into loadAudioDevices() so it runs
  after availability is confirmed from the API
- Show/hide the visualizer toggle button based on fetched availability

media_server/static/js/player.js

@@ -485,7 +485,20 @@ export async function loadAudioDevices() {
         });
         _audioDeviceIconSelect.setValue(select.value, false);
 
+        // Sync visualizerAvailable from the fetched status so that
+        // applyVisualizerMode() and the toggle button are consistent.
+        visualizerAvailable = status.available;
+        const btn = document.getElementById('visualizerToggle');
+        if (btn) btn.style.display = visualizerAvailable ? '' : 'none';
+
         updateAudioDeviceStatus(status);
+
+        // Re-subscribe the WebSocket if the user had the visualizer enabled.
+        if (visualizerEnabled && visualizerAvailable) {
+            if (ws && ws.readyState === WebSocket.OPEN) {
+                ws.send(JSON.stringify({ type: 'enable_visualizer' }));
+            }
+        }
     } catch (e) {
         section.style.display = 'none';
     }

media_server/static/js/websocket.js

@@ -8,7 +8,7 @@ import {
     WS_MAX_RECONNECT_ATTEMPTS, WS_PING_INTERVAL_MS,
     authRequired, showUpdateBanner,
 } from './core.js';
-import { updateUI, visualizerEnabled, visualizerAvailable, setFrequencyData, stopPositionInterpolation, loadAudioDevices } from './player.js';
+import { updateUI, setFrequencyData, stopPositionInterpolation, loadAudioDevices } from './player.js';
 import { loadScripts, loadScriptsTable, displayQuickAccess } from './scripts.js';
 import { loadCallbacksTable } from './callbacks.js';
 import { loadHeaderLinks, loadLinksTable } from './links.js';
@@ -81,9 +81,6 @@ export function connectWebSocket(token) {
         loadLinksTable();
         loadHeaderLinks();
         loadAudioDevices();
-        if (visualizerEnabled && visualizerAvailable) {
-            newWs.send(JSON.stringify({ type: 'enable_visualizer' }));
-        }
     };
 
     newWs.onmessage = (event) => {