Add update checking

lib/data/repository/update_repository_impl.dart

@@ -0,0 +1,59 @@
+import 'package:dio/dio.dart';
+import 'package:fpdart/fpdart.dart';
+import 'package:hiddify/data/repository/exception_handlers.dart';
+import 'package:hiddify/domain/app/app.dart';
+import 'package:hiddify/domain/constants.dart';
+import 'package:hiddify/utils/custom_loggers.dart';
+import 'package:package_info_plus/package_info_plus.dart';
+
+class UpdateRepositoryImpl
+    with ExceptionHandler, InfraLogger
+    implements UpdateRepository {
+  UpdateRepositoryImpl(this.dio);
+
+  final Dio dio;
+
+  @override
+  TaskEither<UpdateFailure, InstalledVersionInfo> getCurrentVersion() {
+    return exceptionHandler(
+      () async {
+        final packageInfo = await PackageInfo.fromPlatform();
+        return right(
+          InstalledVersionInfo(
+            version: packageInfo.version,
+            buildNumber: packageInfo.buildNumber,
+            installerMedia: packageInfo.installerStore,
+          ),
+        );
+      },
+      UpdateFailure.unexpected,
+    );
+  }
+
+  @override
+  TaskEither<UpdateFailure, RemoteVersionInfo> getLatestVersion({
+    bool includePreReleases = false,
+  }) {
+    return exceptionHandler(
+      () async {
+        final response = await dio.get<List>(Constants.githubReleasesApiUrl);
+
+        if (response.statusCode != 200 || response.data == null) {
+          loggy.warning("failed to fetch latest version info");
+          return left(const UpdateFailure.unexpected());
+        }
+
+        final releases = response.data!
+            .map((e) => RemoteVersionInfo.fromJson(e as Map<String, dynamic>));
+        late RemoteVersionInfo latest;
+        if (includePreReleases) {
+          latest = releases.first;
+        } else {
+          latest = releases.firstWhere((e) => e.preRelease == false);
+        }
+        return right(latest);
+      },
+      UpdateFailure.unexpected,
+    );
+  }
+}