feat(client): invite api + provider + auth_api.register 加 inviteCode

client/lib/services/auth_api.dart

@@ -115,12 +115,14 @@ class AuthApi {
     required String code,
     required String password,
     Map<String, dynamic>? device,
+    String? inviteCode,
   }) async {
     final resp = await _post('/v1/auth/register', {
       'email': email,
       'code': code,
       'password': password,
       if (device != null) 'device': device,
+      if (inviteCode != null && inviteCode.isNotEmpty) 'invite_code': inviteCode,
     });
     if (resp.statusCode != 200 && resp.statusCode != 201) {
       _throwFromResponse(resp);

client/lib/services/invite_api.dart

@@ -0,0 +1,35 @@
+// invite_api.dart — 邀请/奖励任务代理端点封装(JWT 经 ApiClient 自动注入)。
+import 'api_client.dart';
+
+class InviteInfo {
+  const InviteInfo({
+    required this.code, required this.link, required this.invited,
+    required this.converted, required this.earnedDays,
+    required this.tgEnabled, required this.tgJoined, required this.channel,
+  });
+  final String code, link, channel;
+  final int invited, converted, earnedDays;
+  final bool tgEnabled, tgJoined;
+
+  factory InviteInfo.fromJson(Map<String, dynamic> j) {
+    final tg = (j['telegram'] as Map<String, dynamic>?) ?? const {};
+    return InviteInfo(
+      code: j['invite_code'] as String? ?? '',
+      link: j['invite_link'] as String? ?? '',
+      invited: (j['invited'] as num?)?.toInt() ?? 0,
+      converted: (j['converted'] as num?)?.toInt() ?? 0,
+      earnedDays: (j['earned_days'] as num?)?.toInt() ?? 0,
+      tgEnabled: tg['enabled'] as bool? ?? false,
+      tgJoined: tg['joined'] as bool? ?? false,
+      channel: tg['channel'] as String? ?? '',
+    );
+  }
+}
+
+class InviteApi {
+  InviteApi(this._c);
+  final ApiClient _c;
+  Future<InviteInfo> fetch() async => InviteInfo.fromJson(await _c.getJson('/v1/invite'));
+  Future<String> telegramStartLink() async =>
+      (await _c.getJson('/v1/tasks/telegram/start'))['deep_link'] as String? ?? '';
+}

client/lib/state/invite_provider.dart

@@ -0,0 +1,25 @@
+// invite_provider.dart — 邀请信息状态装配:复用 apiClientProvider,未登录不打网络。
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+
+import '../services/invite_api.dart';
+import 'account_providers.dart';
+import 'auth_provider.dart';
+
+final inviteApiProvider = Provider<InviteApi>((ref) => InviteApi(ref.watch(apiClientProvider)));
+
+class InviteNotifier extends AsyncNotifier<InviteInfo?> {
+  @override
+  Future<InviteInfo?> build() async {
+    // 未登录返回 null(不打网络);已登录拉取。
+    final token = ref.watch(authProvider).accessToken;
+    if (token == null || token.isEmpty) return null;
+    return ref.read(inviteApiProvider).fetch();
+  }
+
+  Future<void> refresh() async {
+    state = const AsyncLoading();
+    state = await AsyncValue.guard(() => ref.read(inviteApiProvider).fetch());
+  }
+}
+
+final inviteProvider = AsyncNotifierProvider<InviteNotifier, InviteInfo?>(InviteNotifier.new);

client/test/unit/invite_api_test.dart

@@ -0,0 +1,24 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:http/http.dart' as http;
+import 'package:http/testing.dart';
+import 'package:pangolin_vpn/services/api_client.dart';
+import 'package:pangolin_vpn/services/invite_api.dart';
+
+ApiClient _c(MockClient m) => ApiClient(baseUrl: 'http://x', getToken: () => 't', refresh: () async => false, client: m);
+
+void main() {
+  test('fetch 解析邀请信息 + TG 任务态', () async {
+    final api = InviteApi(_c(MockClient((req) async {
+      expect(req.url.path, '/v1/invite');
+      return http.Response('{"invite_code":"ABCD2345","invite_link":"https://x/i/ABCD2345",'
+          '"invited":3,"converted":1,"earned_days":16,'
+          '"telegram":{"enabled":true,"joined":false,"channel":"@pangolin_app"}}', 200);
+    })));
+    final info = await api.fetch();
+    expect(info.code, 'ABCD2345');
+    expect(info.invited, 3);
+    expect(info.earnedDays, 16);
+    expect(info.tgEnabled, true);
+    expect(info.tgJoined, false);
+  });
+}