Add Lidarr library update command and UI trigger

public/app.js

@@ -9,6 +9,7 @@ const dialogArtist = document.getElementById('dialogArtist');
 const trackList = document.getElementById('trackList');
 const sendBtn = document.getElementById('sendBtn');
 const cleanupToggle = document.getElementById('cleanupToggle');
+const updateLibraryBtn = document.getElementById('updateLibraryBtn');
 
 let selectedAlbum = null;
 
@@ -221,6 +222,23 @@ async function sendToLidarr(event) {
   }
 }
 
+async function updateLibrary() {
+  setStatus('Starte Lidarr Bibliothek-Update...');
+  updateLibraryBtn.disabled = true;
+
+  try {
+    const data = await fetchJson('/api/lidarr/update-library', {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' }
+    });
+    setStatus(`Bibliothek-Update gestartet (${data.commandNames.join(', ')}).`);
+  } catch (err) {
+    setStatus(`Fehler beim Bibliothek-Update: ${err.message}`, true);
+  } finally {
+    updateLibraryBtn.disabled = false;
+  }
+}
+
 searchBtn.addEventListener('click', searchSpotify);
 queryInput.addEventListener('keydown', (event) => {
   if (event.key === 'Enter') {
@@ -228,3 +246,4 @@ queryInput.addEventListener('keydown', (event) => {
   }
 });
 sendBtn.addEventListener('click', sendToLidarr);
+updateLibraryBtn.addEventListener('click', updateLibrary);

public/index.html

@@ -22,6 +22,9 @@
           <input type="checkbox" id="cleanupToggle" />
           <span>Ueberfluessige Dateien nach Download loeschen</span>
         </label>
+        <div style="margin-top: 0.8rem;">
+          <button id="updateLibraryBtn" type="button">Lidarr Bibliothek updaten</button>
+        </div>
         <p class="hint">
           Wenn nur einzelne Songs gewaehlt sind, versucht die App unnoetige Track-Dateien in Lidarr zu entfernen.
         </p>