feat: SoundCloud downloader + rename page to Song Importer

- New src/soundcloud.js: resolves SoundCloud URLs via yt-dlp --dump-single-json,
  renders track/playlist preview with per-track download buttons
- Backend POST /api/soundcloud/resolve: extracts metadata (title, artist, genre,
  artwork, duration) directly from SoundCloud — no iTunes lookup needed
- ytdlp.js: sourceUrl param — if set, downloads directly from URL instead of
  ytsearch cascade (used for SoundCloud tracks)
- Spotify importer page renamed to Song Importer, now contains both
  Spotify and SoundCloud sections in one view

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

backend/lib/ytdlp.js

@@ -47,7 +47,7 @@ function buildVariantFilter(title) {
   return parts.length ? parts.join(' & ') : '';
 }
 
-async function downloadTrack({ jobId, artist, albumArtist, title, album, year, trackNum, totalTracks, discNum, discTotal, compilation, genre, artworkUrl, explicit, outputDir, durationMs }) {
+async function downloadTrack({ jobId, artist, albumArtist, title, album, year, trackNum, totalTracks, discNum, discTotal, compilation, genre, artworkUrl, explicit, outputDir, durationMs, sourceUrl }) {
   const mainArtist = albumArtist || artist;
   const safeArtist = sanitize(mainArtist.split(',')[0].trim());
   const safeAlbum  = sanitize(album || 'Singles');
@@ -109,6 +109,15 @@ async function downloadTrack({ jobId, artist, albumArtist, title, album, year, t
   const expectedAudio = path.join(dir, `${trackPrefix}${safeTitle}.${CONFIG.audioFmt}`);
   const hasAudio = () => fs.existsSync(expectedAudio);
 
+  // Direct URL download (e.g. SoundCloud) — skip the ytsearch cascade entirely
+  if (sourceUrl) {
+    log(jobId, `🔗 Direkter Download: ${sourceUrl}`);
+    await spawnYtdlp([sourceUrl, '--no-playlist', ...baseArgs]);
+    const audioFile = hasAudio() ? expectedAudio : null;
+    if (!audioFile) { log(jobId, '⚠️  Download fehlgeschlagen'); return { success: true, dir }; }
+    return embedMetadata({ jobId, audioFile, dir, trackPrefix, safeTitle, artist, mainArtist, album, year, trackNum, totalTracks, discNum, discTotal, compilation, genre, artworkUrl, explicit, title });
+  }
+
   // Fetch YTM search result URLs as a flat list (no channel expansion) and return only
   // actual video URLs (watch?v=…). This prevents yt-dlp from following an artist channel
   // result and treating its uploads as the search result set.

backend/novasonic-server.js

@@ -226,7 +226,8 @@ app.post('/api/spotify/resolve', async (req, res) => {
 
 app.post('/api/download', async (req, res) => {
   const { type, artist, title, album, artworkUrl, collectionId, jobId: clientJobId, explicit,
-          trackNum: bodyTrackNum, totalTracks: bodyTotalTracks, discNum: bodyDiscNum, discTotal: bodyDiscTotal } = req.body;
+          trackNum: bodyTrackNum, totalTracks: bodyTotalTracks, discNum: bodyDiscNum, discTotal: bodyDiscTotal,
+          sourceUrl } = req.body;
   if (!artist || !title) return res.status(400).json({ error: 'artist and title required' });
 
   const jobId = clientJobId || ('job_' + Date.now());
@@ -263,7 +264,7 @@ app.post('/api/download', async (req, res) => {
         } else {
           log(jobId, `📋 Album aus Spotify: "${meta.album}"`);
         }
-        const result = await downloadTrack({ jobId, artist, title, ...meta });
+        const result = await downloadTrack({ jobId, artist, title, ...meta, sourceUrl: sourceUrl || sp.sourceUrl || undefined });
         if (result?.skipped) {
           updateJob(jobId, { status: 'done', progress: 100, message: 'Bereits vorhanden – übersprungen', skipped: true });
         } else {
@@ -350,6 +351,7 @@ app.post('/api/download', async (req, res) => {
               artworkUrl:  itunes.artworkUrl  || track.artworkUrl100  || artworkUrl || '',
               explicit:    track.trackExplicitness === 'explicit',
               durationMs:  itunes.durationMs  || track.durationMs    || undefined,
+              sourceUrl:   track.sourceUrl    || undefined,
             });
           }));
           for (let j = 0; j < batchResults.length; j++) {
@@ -389,6 +391,68 @@ app.get('/api/jobs', (req, res) => {
   res.json(Array.from(jobs.values()).sort((a, b) => b.createdAt - a.createdAt).slice(0, 50));
 });
 
+// ─── SOUNDCLOUD RESOLVE ──────────────────────────────────────────────────────
+app.post('/api/soundcloud/resolve', async (req, res) => {
+  const { url } = req.body;
+  if (!url || !url.includes('soundcloud.com')) return res.status(400).json({ error: 'SoundCloud URL required' });
+  try {
+    const { execFile } = require('child_process');
+    const data = await new Promise((resolve, reject) => {
+      execFile(
+        CONFIG.ytdlpBin,
+        ['--flat-playlist', '--dump-single-json', '--no-warnings', url],
+        { timeout: 30000, maxBuffer: 5 * 1024 * 1024 },
+        (err, stdout, stderr) => {
+          if (err) return reject(new Error(`yt-dlp: ${stderr?.trim() || err.message}`));
+          try { resolve(JSON.parse(stdout.trim())); }
+          catch { reject(new Error('yt-dlp: ungültige Ausgabe')); }
+        }
+      );
+    });
+
+    const isPlaylist = data._type === 'playlist' || Array.isArray(data.entries);
+    if (isPlaylist) {
+      const entries = data.entries || [];
+      const tracks = entries.map(e => ({
+        trackName:   e.title   || '',
+        artistName:  e.uploader || e.artist || data.uploader || '',
+        artworkUrl:  e.thumbnail || '',
+        duration:    e.duration  || 0,
+        genre:       e.genre    || '',
+        sourceUrl:   e.url || e.webpage_url || '',
+      }));
+      res.json({
+        type: 'playlist',
+        name: data.title || data.uploader || 'SoundCloud Playlist',
+        artist: data.uploader || '',
+        artworkUrl: data.thumbnail || tracks[0]?.artworkUrl || '',
+        tracks,
+      });
+    } else {
+      const track = {
+        trackName:  data.title    || '',
+        artistName: data.uploader || data.artist || '',
+        artworkUrl: data.thumbnail || '',
+        duration:   data.duration  || 0,
+        genre:      data.genre    || '',
+        album:      data.album    || '',
+        year:       data.upload_date ? parseInt(data.upload_date.slice(0, 4), 10) : undefined,
+        sourceUrl:  url,
+      };
+      res.json({
+        type: 'track',
+        name: track.trackName,
+        artist: track.artistName,
+        artworkUrl: track.artworkUrl,
+        tracks: [track],
+      });
+    }
+  } catch (e) {
+    console.error('[soundcloud/resolve]', e.message);
+    res.status(500).json({ error: e.message });
+  }
+});
+
 // ─── MUSICBRAINZ LOOKUP ──────────────────────────────────────────────────────
 app.get('/api/musicbrainz/lookup', async (req, res) => {
   const { artist, title } = req.query;