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/core/enums/auth_state.dart

@@ -1,24 +0,0 @@
-enum AuthState {
-  loggedOut,
-  authenticating,
-  authenticated,
-  error;
-
-  String get displayName {
-    switch (this) {
-      case AuthState.loggedOut:
-        return 'Logged Out';
-      case AuthState.authenticating:
-        return 'Authenticating';
-      case AuthState.authenticated:
-        return 'Authenticated';
-      case AuthState.error:
-        return 'Error';
-    }
-  }
-
-  bool get isLoggedIn => this == AuthState.authenticated;
-  bool get isLoggedOut => this == AuthState.loggedOut;
-  bool get isAuthenticating => this == AuthState.authenticating;
-  bool get hasError => this == AuthState.error;
-}

swingmusic_mobile/lib/core/enums/playback_mode.dart

@@ -1,50 +0,0 @@
-enum RepeatMode {
-  off,
-  one,
-  all;
-
-  String get displayName {
-    switch (this) {
-      case RepeatMode.off:
-        return 'Off';
-      case RepeatMode.one:
-        return 'Repeat One';
-      case RepeatMode.all:
-        return 'Repeat All';
-    }
-  }
-
-  RepeatMode next() {
-    switch (this) {
-      case RepeatMode.off:
-        return RepeatMode.all;
-      case RepeatMode.all:
-        return RepeatMode.one;
-      case RepeatMode.one:
-        return RepeatMode.off;
-    }
-  }
-}
-
-enum ShuffleMode {
-  off,
-  on;
-
-  String get displayName {
-    switch (this) {
-      case ShuffleMode.off:
-        return 'Off';
-      case ShuffleMode.on:
-        return 'On';
-    }
-  }
-
-  ShuffleMode toggle() {
-    switch (this) {
-      case ShuffleMode.off:
-        return ShuffleMode.on;
-      case ShuffleMode.on:
-        return ShuffleMode.off;
-    }
-  }
-}