Recursive album discovery + Jellyfin Playlist Generator integration

scanner.py: collect_album_dirs() now recursively finds album dirs
- Dirs with audio files at root → album
- Dirs with disc subdirs (CD1/CD2) and no root audio → multi-CD album
- Container dirs without audio → recurse into subdirs

music_enricher.py:
- After execute_album(), auto-discovers jellyfin_playlist_generator.py
  in ../Jellyfin_Playlist_Generator/ (or via --playlist-generator PATH)
- Calls generate_playlist() directly via importlib — no subprocess,
  no destructive cleanup_all_playlists, targeted to the enriched album
- New --playlist-generator CLI option for custom generator path

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

scanner.py

@@ -89,11 +89,49 @@ def _scan_dir(current: Path, album_dir: Path, result: AlbumScan, recurse: bool)
 
 
 def collect_album_dirs(root: Path) -> List[Path]:
-    dirs: List[Path] = []
+    """
+    Findet rekursiv alle Album-Verzeichnisse unterhalb von root.
+    Ein Verzeichnis gilt als Album wenn:
+    - es direkt Audio-Dateien enthält, ODER
+    - es keine direkten Audio-Dateien hat aber Disc-Unterordner mit Audio (Multi-CD).
+    Container-Verzeichnisse ohne Audio werden rekursiv durchsucht.
+    """
+    result: List[Path] = []
+    _find_albums(root, result)
+    return result
+
+
+def _has_local_audio(path: Path) -> bool:
     try:
-        for item in sorted(root.iterdir()):
-            if item.is_dir() and not _is_hidden(item.name):
-                dirs.append(item)
+        return any(
+            e.suffix.lower() in AUDIO_EXTENSIONS
+            for e in path.iterdir()
+            if e.is_file() and not _is_hidden(e.name)
+        )
+    except (PermissionError, OSError):
+        return False
+
+
+def _find_albums(current: Path, result: List[Path]) -> None:
+    try:
+        entries = sorted(current.iterdir())
+        subdirs = [e for e in entries if e.is_dir() and not _is_hidden(e.name)]
     except (PermissionError, OSError) as e:
-        print(f"⚠️ Lesefehler {root}: {e}", file=sys.stderr)
-    return dirs
+        print(f"⚠️ Lesefehler {current}: {e}", file=sys.stderr)
+        return
+
+    # Verzeichnis enthält direkt Audio → Album
+    if any(e.is_file() and not _is_hidden(e.name) and e.suffix.lower() in AUDIO_EXTENSIONS
+           for e in entries):
+        result.append(current)
+        return
+
+    # Disc-Unterordner mit Audio → Multi-CD-Album (scan_album übernimmt die Disc-Logik)
+    disc_dirs = [d for d in subdirs if _is_disc_dir(d.name)]
+    if disc_dirs and any(_has_local_audio(d) for d in disc_dirs):
+        result.append(current)
+        return
+
+    # Container-Verzeichnis → rekursiv weiter suchen
+    for subdir in subdirs:
+        _find_albums(subdir, result)