Add NAVIDROME_URL autofill, remove Navidrome scan trigger

- Frontend reads window.NS_SERVER_URL from config.js (injected at container start via docker-entrypoint.sh) and pre-fills the setup screen
- Removed triggerNaviScan from frontend and backend (Navidrome auto-scans on file change)
- Removed NAVIDROME_USER/PASS from backend and compose

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app.js

@@ -110,6 +110,11 @@ function disconnect(){
 window.addEventListener('load',()=>{
   const saved=localStorage.getItem('ns_cfg');
   if(saved){cfg=JSON.parse(saved);startApp()}
+  // Autofill server URL from Docker env (set via config.js)
+  if(window.NS_SERVER_URL){
+    const el=document.getElementById('srv-url');
+    if(el&&!el.value)el.value=window.NS_SERVER_URL;
+  }
   document.getElementById('srv-pass').addEventListener('keydown',e=>{if(e.key==='Enter')doConnect()});
   audio.addEventListener('timeupdate',updateProgress);
   audio.addEventListener('ended',onEnded);
@@ -916,13 +921,9 @@ async function pollJob(jobId){
     const d=await res.json();
     updateJob(jobId,d.status,d.message,d.progress);
     if(d.status!=='done'&&d.status!=='error')setTimeout(()=>pollJob(jobId),1500);
-    else if(d.status==='done'){toast(`✅ ${jobs[jobId]?.title||'Track'} gespeichert!`);triggerNaviScan()}
+    else if(d.status==='done'){toast(`✅ ${jobs[jobId]?.title||'Track'} gespeichert!`)}
   }catch{updateJob(jobId,'error','Status-Abfrage fehlgeschlagen')}
 }
-async function triggerNaviScan(){
-  try{await api('startScan')}catch{}
-}
-
 // ─── LOCAL DOWNLOAD (from Navidrome) ───
 function dlSongLocal(s){
   const a=document.createElement('a');a.href=downloadUrl(s.id);