fix(flutter): remove incorrect .dio accessor from dioClientProvider calls

dioClientProvider returns Dio directly (not a wrapper class).
Removed spurious .dio property access from 3 files:
- in_site_notification_repository.dart
- notification_preferences_page.dart
- referral_repository.dart

Also fix _SettingsRow usage in profile_page: replaced incorrect
`label`/`subtitle` params with the correct `title`/`iconBg` params.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

it0_app/lib/features/notifications/data/in_site_notification_repository.dart

@@ -45,6 +45,6 @@ class InSiteNotificationRepository {
 
 final inSiteNotificationRepositoryProvider =
     Provider<InSiteNotificationRepository>((ref) {
-  final dio = ref.watch(dioClientProvider).dio;
+  final dio = ref.watch(dioClientProvider);
   return InSiteNotificationRepository(dio);
 });

it0_app/lib/features/notifications/presentation/pages/notification_preferences_page.dart

@@ -6,7 +6,7 @@ import '../../../../core/network/dio_client.dart';
 // ── Providers ──────────────────────────────────────────────────────────────
 
 final _channelPrefsProvider = FutureProvider.autoDispose<List<NotificationChannelPreference>>((ref) async {
-  final dio = ref.watch(dioClientProvider).dio;
+  final dio = ref.watch(dioClientProvider);
   final res = await dio.get('/api/v1/notifications/channels/me/preferences');
   final list = res.data as List;
   return list
@@ -31,7 +31,7 @@ class _NotificationPreferencesPageState extends ConsumerState<NotificationPrefer
     if (_pendingChanges.isEmpty) return;
     setState(() => _saving = true);
     try {
-      final dio = ref.read(dioClientProvider).dio;
+      final dio = ref.read(dioClientProvider);
       final preferences = _pendingChanges.entries
           .map((e) => {'channelKey': e.key, 'enabled': e.value})
           .toList();

it0_app/lib/features/profile/presentation/pages/profile_page.dart

@@ -89,9 +89,8 @@ class _ProfilePageState extends ConsumerState<ProfilePage> {
               _InSiteMessageRow(subtitleColor: subtitleColor),
               _SettingsRow(
                 icon: Icons.tune_outlined,
-                label: '通知偏好设置',
-                subtitle: '管理各类通知的订阅开关',
-                subtitleColor: subtitleColor,
+                iconBg: const Color(0xFF8B5CF6),
+                title: '通知偏好设置',
                 onTap: () => context.push('/notifications/preferences'),
               ),
             ],

it0_app/lib/features/referral/data/referral_repository.dart

@@ -52,6 +52,6 @@ class ReferralRepository {
 // ── Riverpod provider ────────────────────────────────────────────────────────
 
 final referralRepositoryProvider = Provider<ReferralRepository>((ref) {
-  final dio = ref.watch(dioClientProvider).dio;
+  final dio = ref.watch(dioClientProvider);
   return ReferralRepository(dio);
 });