fix: circular import causing navigate undefined; unified importer input

- Remove top-level ui.js import from soundcloud.js (broke views.js→soundcloud.js→ui.js→views.js cycle)
- Use window.executeSpotifyDownload() instead to avoid the circular dep
- Merge Spotify + SoundCloud into one unified URL input that auto-detects
  the service and colors the badge/button accordingly
- resolveImporterLink() routes to the correct handler based on URL

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

src/soundcloud.js

@@ -1,34 +1,25 @@
 import { S } from './state.js';
 import { esc, toast } from './utils.js';
-// Circular imports — safe (only used inside function bodies)
-import { executeSpotifyDownload } from './ui.js';
 
 export function loadSoundCloudImporter() {
-  const input = document.getElementById('sc-link-input');
-  if (!input?.value) _showHint();
+  // Hint is managed by the unified importer input in spotify.js
 }
 
 export function clearSoundCloudPreview() {
-  if (!document.getElementById('sc-link-input')?.value) _showHint();
-}
-
-function _showHint() {
-  document.getElementById('sc-importer-hint').style.display  = '';
-  document.getElementById('sc-preview').style.display        = 'none';
+  // no-op — handled by onImporterInput
 }
 
 export async function resolveSoundCloudLink() {
-  const url = document.getElementById('sc-link-input')?.value.trim();
+  const url = document.getElementById('sc-link-input')?.value.trim()
+           || document.getElementById('importer-link-input')?.value.trim();
   if (!url) return;
   if (!url.includes('soundcloud.com')) { toast('⚠ Kein SoundCloud-Link'); return; }
   if (!S.cfg.backendUrl) { toast('⚠ Backend URL in Einstellungen konfigurieren'); return; }
 
-  const hint    = document.getElementById('sc-importer-hint');
   const preview = document.getElementById('sc-preview');
   const inner   = document.getElementById('sc-preview-inner');
   const section = document.getElementById('sc-tracks-section');
 
-  hint.style.display    = 'none';
   preview.style.display = '';
   section.style.display = 'none';
   inner.innerHTML = '<div class="spinner"></div>';
@@ -59,7 +50,7 @@ export async function resolveSoundCloudLink() {
 export function scDlAll() {
   const data = window._scResolved;
   if (!data) return;
-  executeSpotifyDownload({
+  window.executeSpotifyDownload({
     type: 'playlist',
     title: data.name,
     artist: data.artist,
@@ -72,7 +63,7 @@ export function scDlSingle() {
   const data = window._scResolved;
   if (!data?.tracks?.[0]) return;
   const t = data.tracks[0];
-  executeSpotifyDownload({
+  window.executeSpotifyDownload({
     type: 'track',
     title: t.trackName,
     artist: t.artistName,
@@ -85,7 +76,7 @@ export function scDlTrack(idx) {
   const data = window._scResolved;
   const t = data?.tracks?.[idx];
   if (!t) return;
-  executeSpotifyDownload({
+  window.executeSpotifyDownload({
     type: 'track',
     title: t.trackName,
     artist: t.artistName,