m3e theme extension on colorscheme

snippet.dart

// Convenience creation helpers to install M3ETheme with minimal boilerplate.
extension M3EColorSchemeAccessors on ColorScheme {
  /// Creates a ThemeData from this ColorScheme and installs the M3ETheme
  /// extension in one call.
  ///
  /// Example:
  ///   final theme = ColorScheme.fromSeed(seedColor: Colors.teal).toM3EThemeData();
  ThemeData toM3EThemeData({
    bool useMaterial3 = true,
    M3ETheme? override,
    ThemeData? base,
  }) {
    final ThemeData seed =
        base ?? ThemeData(useMaterial3: useMaterial3, colorScheme: this);
    return withM3ETheme(seed, override: override);
  }
}