feat: refresh UI quicker when user is interacting

The current 1sec delay can make the UI feel a bit laggy, so kick off
an refresh sooner whenever we react to user input.

webui-page/webui.js

@@ -19,6 +19,8 @@ function send(command, param){
   request.open("post", path);
 
   request.send(null);
+  // Kick off a refresh quickly in response to user input.
+  refreshStatus(100);
 }
 
 function togglePlaylist() {
@@ -457,6 +459,17 @@ function handleStatusResponse(json) {
   }
 }
 
+let nextRefresh;
+function refreshStatus(timeout) {
+  if (nextRefresh) {
+    return;
+  }
+  nextRefresh = setTimeout(() => {
+    nextRefresh = undefined;
+    status();
+  }, timeout);
+}
+
 function status(){
   var request = new XMLHttpRequest();
   request.open("get", "/api/status");