Add basic flavors

lib/features/common/app_update_notifier.dart

@@ -0,0 +1,33 @@
+import 'package:hiddify/core/core_providers.dart';
+import 'package:hiddify/data/data_providers.dart';
+import 'package:hiddify/domain/app/app.dart';
+import 'package:hiddify/utils/utils.dart';
+import 'package:riverpod_annotation/riverpod_annotation.dart';
+
+part 'app_update_notifier.g.dart';
+
+@Riverpod(keepAlive: true)
+class AppUpdateNotifier extends _$AppUpdateNotifier with AppLogger {
+  @override
+  Future<RemoteVersionInfo?> build() async {
+    loggy.debug("checking for update");
+    final currentVersion = ref.watch(appInfoProvider).version;
+    return ref
+        .watch(appRepositoryProvider)
+        .getLatestVersion(includePreReleases: true)
+        .match(
+      (l) {
+        loggy.warning("failed to get latest version, $l");
+        throw l;
+      },
+      (remote) {
+        if (remote.version.compareTo(currentVersion) > 0) {
+          loggy.info("new version available: $remote");
+          return remote;
+        }
+        loggy.info("already using latest version[$currentVersion], remote: $remote");
+        return null;
+      },
+    ).run();
+  }
+}