fix: prevent full-screen spinner on background stream polls

client/src/App.jsx

@@ -421,12 +421,16 @@ export default function App() {
     };
   }, []);
 
-  // Fetch stats when selected stream changes
+  // Fetch stats when selected stream changes (with loading spinner)
+  useEffect(() => {
+    if (selectedStreamId && serverStatus === 'online') {
+      fetchAllStats(true);
+    }
+  }, [selectedStreamId, serverStatus]);
+
+  // Manage polling intervals when selected stream changes or streams update
   useEffect(() => {
     if (selectedStreamId && serverStatus === 'online') {
-      fetchAllStats();
-      
-      // Setup polling if the selected stream is live (end_time is null)
       const selectedStream = streams.find(s => s.id === parseInt(selectedStreamId));
       const isLive = selectedStream && !selectedStream.end_time;