optimization: desktop UI (#747)

lib/data/provider/app.dart

@@ -1,7 +1,27 @@
 import 'package:flutter/material.dart';
+import 'package:freezed_annotation/freezed_annotation.dart';
+import 'package:riverpod_annotation/riverpod_annotation.dart';
 
-final class AppProvider {
-  const AppProvider._();
+part 'app.g.dart';
+part 'app.freezed.dart';
 
-  static BuildContext? ctx;
+@freezed
+class AppState with _$AppState {
+  const factory AppState({
+    @Default(false) bool desktopMode,
+  }) = _AppState;
+}
+
+@Riverpod(keepAlive: true)
+class AppProvider extends _$AppProvider {
+  static BuildContext? ctx;
+
+  @override
+  AppState build() {
+    return const AppState();
+  }
+
+  void setDesktop(bool desktopMode) {
+    state = state.copyWith(desktopMode: desktopMode);
+  }
 }