fix(ui): fall back to polling when websocket is unavailable

Poll the state endpoint while the WebSocket is not open so browsers that fail to establish the socket still receive initial state and continue updating the UI. Retain WebSocket streaming as the primary transport.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

ui/src/api.rs

@@ -17,13 +17,32 @@ pub fn connect(on_state: impl Fn(String) + 'static) {
     let Some(loc) = web_sys::window().map(|w| w.location()) else {
         return;
     };
+    let on_state = Rc::new(on_state);
     let proto = if loc.protocol().is_ok_and(|p| p == "https:") {
         "wss"
     } else {
         "ws"
     };
     let Ok(host) = loc.host() else { return };
-    open(format!("{proto}://{host}/ws"), Rc::new(on_state));
+    open(format!("{proto}://{host}/ws"), on_state.clone());
+
+    spawn_local(async move {
+        loop {
+            TimeoutFuture::new(1000).await;
+            let connected = SOCKET.with(|socket| {
+                socket
+                    .borrow()
+                    .as_ref()
+                    .is_some_and(|socket| socket.ready_state() == WebSocket::OPEN)
+            });
+            if connected {
+                continue;
+            }
+            if let Some(state) = get_text("/api/state").await {
+                on_state(state);
+            }
+        }
+    });
 }
 
 fn open(url: String, on_state: Rc<dyn Fn(String)>) {