fix: reload config after save so viewer toggle state is correct

public/app.js

@@ -442,7 +442,8 @@ document.getElementById('btn-save').addEventListener('click', async () => {
         });
         const j = await r.json();
         if (j.success) {
-            // Reload cameras from the server.
+            // Reload config and cameras from the server.
+            await loadConfig();
             await loadCameras();
             renderLiveGrid();
             renderPlaybackCameras();