Fix download: return URL for client-side download

ui.ts

@@ -327,11 +327,25 @@ function render(f,append){
   else el.innerHTML=html;
 }
 
-function download(i){
+async function download(i){
   var s=songs[i];if(!s||!s.videoId)return;
-  var title=encodeURIComponent(s.title||'audio');
-  var artist=encodeURIComponent(s.artists?.map(a=>a.name).join(', ')||'');
-  window.open('/api/download?id='+s.videoId+'&title='+title+'&artist='+artist,'_blank');
+  var btn=document.querySelectorAll('.dl-btn')[i];
+  if(btn){btn.textContent='...';btn.disabled=true;}
+  try{
+    var res=await fetch('/api/download?id='+s.videoId+'&redirect=0');
+    var data=await res.json();
+    if(!data.success||!data.url){alert('Download failed: '+(data.error||'No URL'));return;}
+    // Create download link
+    var a=document.createElement('a');
+    a.href=data.url;
+    a.download=data.filename||'audio.m4a';
+    a.target='_blank';
+    a.rel='noopener';
+    document.body.appendChild(a);
+    a.click();
+    document.body.removeChild(a);
+  }catch(e){alert('Download error');}
+  finally{if(btn){btn.textContent='↓';btn.disabled=false;}}
 }
 
 function play(i){