Fix mobile app submodule initialization and cleanup

- Removed incorrect swingmusic_mobile directory
- Properly initialized swingmusic_mobile submodule from swingmusic-mobile.git
- Clean submodule configuration for unified release workflow

swingmusic_mobile/lib/data/models/folder_model.dart

@@ -1,123 +0,0 @@
-import 'package:equatable/equatable.dart';
-import 'track_model.dart';
-
-class FolderModel extends Equatable {
-  final String name;
-  final String path;
-  final String? parent;
-  final int trackcount;
-  final List<FolderModel> subfolders;
-  final List<TrackModel> tracks;
-  final String? image;
-  final bool isFavorite;
-
-  const FolderModel({
-    required this.name,
-    required this.path,
-    this.parent,
-    this.trackcount = 0,
-    this.subfolders = const [],
-    this.tracks = const [],
-    this.image,
-    this.isFavorite = false,
-  });
-
-  FolderModel copyWith({
-    String? name,
-    String? path,
-    String? parent,
-    int? trackcount,
-    List<FolderModel>? subfolders,
-    List<TrackModel>? tracks,
-    String? image,
-    bool? isFavorite,
-  }) {
-    return FolderModel(
-      name: name ?? this.name,
-      path: path ?? this.path,
-      parent: parent ?? this.parent,
-      trackcount: trackcount ?? this.trackcount,
-      subfolders: subfolders ?? this.subfolders,
-      tracks: tracks ?? this.tracks,
-      image: image ?? this.image,
-      isFavorite: isFavorite ?? this.isFavorite,
-    );
-  }
-
-  factory FolderModel.fromJson(Map<String, dynamic> json) {
-    return FolderModel(
-      name: json['name'] ?? '',
-      path: json['path'] ?? '',
-      parent: json['parent'],
-      trackcount: json['trackcount'] ?? 0,
-      subfolders: (json['subfolders'] as List<dynamic>?)
-          ?.map((folder) => FolderModel.fromJson(folder))
-          .toList() ?? [],
-      tracks: (json['tracks'] as List<dynamic>?)
-          ?.map((track) => TrackModel.fromJson(track))
-          .toList() ?? [],
-      image: json['image'],
-      isFavorite: json['is_favorite'] ?? false,
-    );
-  }
-
-  Map<String, dynamic> toJson() {
-    return {
-      'name': name,
-      'path': path,
-      'parent': parent,
-      'trackcount': trackcount,
-      'subfolders': subfolders.map((folder) => folder.toJson()).toList(),
-      'tracks': tracks.map((track) => track.toJson()).toList(),
-      'image': image,
-      'is_favorite': isFavorite,
-    };
-  }
-
-  @override
-  List<Object?> get props => [
-        name,
-        path,
-        parent,
-        trackcount,
-        subfolders,
-        tracks,
-        image,
-        isFavorite,
-      ];
-}
-
-class FoldersAndTracksModel extends Equatable {
-  final List<FolderModel> folders;
-  final List<TrackModel> tracks;
-  final String currentPath;
-
-  const FoldersAndTracksModel({
-    required this.folders,
-    required this.tracks,
-    required this.currentPath,
-  });
-
-  factory FoldersAndTracksModel.fromJson(Map<String, dynamic> json) {
-    return FoldersAndTracksModel(
-      folders: (json['folders'] as List<dynamic>?)
-          ?.map((folder) => FolderModel.fromJson(folder))
-          .toList() ?? [],
-      tracks: (json['tracks'] as List<dynamic>?)
-          ?.map((track) => TrackModel.fromJson(track))
-          .toList() ?? [],
-      currentPath: json['current_path'] ?? '',
-    );
-  }
-
-  Map<String, dynamic> toJson() {
-    return {
-      'folders': folders.map((folder) => folder.toJson()).toList(),
-      'tracks': tracks.map((track) => track.toJson()).toList(),
-      'current_path': currentPath,
-    };
-  }
-
-  @override
-  List<Object?> get props => [folders, tracks, currentPath];
-}