feat(ui): add Mornye glass theme and adaptive music player

Add a selectable Mornye theme with shared glass controls, dialogs, sheets, notifications, and collection headers while retaining Material components.

Update player artwork, lyrics transitions and highlighting, synchronized rolling time labels, volume controls, and compact navigation. Unify metadata, Library, search, and extension surfaces; preserve restored artwork and report extension load failures.

Validation: full Flutter analyzer clean; 713 tests passed and 4 skipped; pinned Dart formatting and diff checks passed; signed ARM64 and ARM32 release APKs built and verified.

lib/models/theme_settings.dart

@@ -4,6 +4,15 @@ const String kThemeModeKey = 'theme_mode';
 const String kUseDynamicColorKey = 'use_dynamic_color';
 const String kSeedColorKey = 'seed_color';
 const String kUseAmoledKey = 'use_amoled';
+const String kThemeStyleKey = 'theme_style';
+
+enum AppThemeStyle { material, mornye }
+
+AppThemeStyle themeStyleFromString(String? value) =>
+    AppThemeStyle.values.firstWhere(
+      (style) => style.name == value,
+      orElse: () => AppThemeStyle.material,
+    );
 
 /// Default Spotify green color for fallback
 const int kDefaultSeedColor = 0xFF1DB954;
@@ -13,12 +22,14 @@ class ThemeSettings {
   final bool useDynamicColor;
   final int seedColorValue;
   final bool useAmoled;
+  final AppThemeStyle style;
 
   const ThemeSettings({
     this.themeMode = ThemeMode.system,
     this.useDynamicColor = true,
     this.seedColorValue = kDefaultSeedColor,
     this.useAmoled = false,
+    this.style = AppThemeStyle.material,
   });
 
   Color get seedColor => Color(seedColorValue);
@@ -28,12 +39,14 @@ class ThemeSettings {
     bool? useDynamicColor,
     int? seedColorValue,
     bool? useAmoled,
+    AppThemeStyle? style,
   }) {
     return ThemeSettings(
       themeMode: themeMode ?? this.themeMode,
       useDynamicColor: useDynamicColor ?? this.useDynamicColor,
       seedColorValue: seedColorValue ?? this.seedColorValue,
       useAmoled: useAmoled ?? this.useAmoled,
+      style: style ?? this.style,
     );
   }
 
@@ -42,6 +55,7 @@ class ThemeSettings {
     kUseDynamicColorKey: useDynamicColor,
     kSeedColorKey: seedColorValue,
     kUseAmoledKey: useAmoled,
+    kThemeStyleKey: style.name,
   };
 
   factory ThemeSettings.fromJson(Map<String, dynamic> json) {
@@ -50,6 +64,7 @@ class ThemeSettings {
       useDynamicColor: json[kUseDynamicColorKey] as bool? ?? true,
       seedColorValue: json[kSeedColorKey] as int? ?? kDefaultSeedColor,
       useAmoled: json[kUseAmoledKey] as bool? ?? false,
+      style: themeStyleFromString(json[kThemeStyleKey] as String?),
     );
   }
 
@@ -60,7 +75,8 @@ class ThemeSettings {
         other.themeMode == themeMode &&
         other.useDynamicColor == useDynamicColor &&
         other.seedColorValue == seedColorValue &&
-        other.useAmoled == useAmoled;
+        other.useAmoled == useAmoled &&
+        other.style == style;
   }
 
   @override
@@ -68,7 +84,8 @@ class ThemeSettings {
       themeMode.hashCode ^
       useDynamicColor.hashCode ^
       seedColorValue.hashCode ^
-      useAmoled.hashCode;
+      useAmoled.hashCode ^
+      style.hashCode;
 }
 
 ThemeMode themeModeFromString(String? value) {