feat(app): offline-кэш на остальных экранах — фаза 5

accounts, cashflow, categories, goals, income, portfolio (+instrument),
rebalance, tax, rules переведены на Cached<T> по контракту
docs/ai/offline-cache.md. Общие/второстепенные селекторы (scopesProvider,
categoriesListProvider и т.п.) оставлены как есть — не основной контент
экрана. sync_page.dart и settings_page.dart не тронуты (первый — заменён
health-page отдельно, второй — чистые действия без списка для баннера).

app/lib/features/rebalance/data/rebalance_api.dart

@@ -12,6 +12,7 @@ library;
 import 'package:decimal/decimal.dart';
 import 'package:dio/dio.dart';
 
+import '../../../core/cache/cached.dart';
 import '../../../core/utils/json.dart';
 
 /// The dimensions targets can be set along, as wire strings (`AssetClass` is never exposed
@@ -214,12 +215,14 @@ class RebalanceApi {
   /// is per-dimension, so the set has to be addressable per-dimension as well. Sending
   /// `dimension` is harmless for a server that ignores it and necessary for one that does
   /// not — revisit once the route is in the spec.
-  Future<TargetSet> getTargets(int portfolioId, {String dimension = 'asset_class'}) async {
+  /// See `docs/ai/offline-cache.md`: this hand-written client returns `Cached<T>` directly
+  /// (there is no generated `Response<T>` for the screen to unwrap `r.cached` from).
+  Future<Cached<TargetSet>> getTargets(int portfolioId, {String dimension = 'asset_class'}) async {
     final r = await _dio.get<Map<String, dynamic>>(
       '$_base/$portfolioId/targets',
       queryParameters: {'dimension': dimension},
     );
-    return TargetSet.fromJson(r.data ?? const {});
+    return Cached(TargetSet.fromJson(r.data ?? const {}), fetchedAt: r.extra['fetchedAt'] as DateTime?);
   }
 
   /// Full replacement of one dimension — partial updates are not supported by the contract.
@@ -231,7 +234,7 @@ class RebalanceApi {
     return TargetSet.fromJson(r.data ?? const {});
   }
 
-  Future<RebalancePlan> plan(
+  Future<Cached<RebalancePlan>> plan(
     int portfolioId, {
     String dimension = 'asset_class',
     String? cashAvailable,
@@ -240,6 +243,9 @@ class RebalanceApi {
       '$_base/$portfolioId/rebalance',
       queryParameters: {'dimension': dimension, 'cash_available': ?cashAvailable},
     );
-    return RebalancePlan.fromJson(r.data ?? const {});
+    return Cached(
+      RebalancePlan.fromJson(r.data ?? const {}),
+      fetchedAt: r.extra['fetchedAt'] as DateTime?,
+    );
   }
 }

app/lib/features/rebalance/plan_tab.dart

@@ -31,7 +31,8 @@ class RebalancePlanTab extends ConsumerWidget {
       child: AsyncValueView(
         value: plan,
         onRetry: () => ref.invalidate(rebalancePlanProvider),
-        data: (data) {
+        data: (cached) {
+          final data = cached.data;
           if (data == null) {
             return const EmptyState(
               icon: Icons.balance,

app/lib/features/rebalance/providers.dart

@@ -1,6 +1,7 @@
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 
 import '../../core/api/api_client.dart';
+import '../../core/cache/cached.dart';
 import '../portfolio/providers.dart' show scopeProvider, scopesProvider;
 import 'data/rebalance_api.dart';
 
@@ -38,18 +39,20 @@ final targetDimensionProvider = StateProvider<String>((ref) => 'asset_class');
 /// What-if cash for the recommendations, as a decimal string. Null = use the real balance.
 final whatIfCashProvider = StateProvider<String?>((ref) => null);
 
-final targetsProvider = FutureProvider.autoDispose<TargetSet>((ref) async {
+/// See `docs/ai/offline-cache.md`. No portfolio selected yet is a live, empty answer — not a
+/// stale one — so it is wrapped with `fetchedAt: null` rather than left unwrapped.
+final targetsProvider = FutureProvider.autoDispose<Cached<TargetSet>>((ref) async {
   final id = ref.watch(selectedPortfolioProvider);
   final dimension = ref.watch(targetDimensionProvider);
-  if (id == null) return TargetSet(dimension: dimension);
+  if (id == null) return Cached(TargetSet(dimension: dimension));
   return ref.watch(rebalanceApiProvider).getTargets(id, dimension: dimension);
 });
 
-final rebalancePlanProvider = FutureProvider.autoDispose<RebalancePlan?>((ref) async {
+final rebalancePlanProvider = FutureProvider.autoDispose<Cached<RebalancePlan?>>((ref) async {
   final id = ref.watch(selectedPortfolioProvider);
   final dimension = ref.watch(targetDimensionProvider);
   final cash = ref.watch(whatIfCashProvider);
-  if (id == null) return null;
+  if (id == null) return const Cached(null);
   return ref.watch(rebalanceApiProvider).plan(id, dimension: dimension, cashAvailable: cash);
 });
 

app/lib/features/rebalance/rebalance_page.dart

@@ -1,8 +1,10 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 
+import '../../core/cache/cached.dart';
 import '../../core/widgets/async_value_view.dart';
 import '../../core/widgets/empty_state.dart';
+import '../../core/widgets/stale_banner.dart';
 import '../portfolio/labels.dart' show dimensionLabels;
 import 'data/rebalance_api.dart';
 import 'plan_tab.dart';
@@ -12,12 +14,21 @@ import 'targets_tab.dart';
 /// Ребалансировка: the target weights on one tab, the resulting recommendations on the
 /// other. Both are per portfolio and per dimension, so the pickers live in the app bar and
 /// drive both tabs at once.
+///
+/// One offline banner covers both tabs (`docs/ai/offline-cache.md`) — both providers are
+/// already watched by their own tab, so watching them again here to compute it costs
+/// nothing extra. `portfoliosProvider` itself is a selector derived from the un-cached
+/// `scopesProvider` (see `portfolio/providers.dart`) and does not contribute a `fetchedAt`.
 class RebalancePage extends ConsumerWidget {
   const RebalancePage({super.key});
 
   @override
   Widget build(BuildContext context, WidgetRef ref) {
     final portfolios = ref.watch(portfoliosProvider);
+    final stale = oldestFetch([
+      ref.watch(targetsProvider).valueOrNull?.fetchedAt,
+      ref.watch(rebalancePlanProvider).valueOrNull?.fetchedAt,
+    ]);
 
     return DefaultTabController(
       length: 2,
@@ -37,27 +48,38 @@ class RebalancePage extends ConsumerWidget {
             tabs: [Tab(text: 'Целевые веса'), Tab(text: 'Рекомендации')],
           ),
         ),
-        body: AsyncValueView(
-          value: portfolios,
-          onRetry: () => ref.invalidate(portfoliosProvider),
-          data: (list) {
-            if (list.isEmpty) {
-              return const EmptyState(
-                icon: Icons.pie_chart_outline,
-                message: 'Портфелей пока нет.\n'
-                    'Ребалансировка считается по портфелю: заведите его в настройках счетов.',
-              );
-            }
-            final selected = ref.watch(selectedPortfolioProvider);
-            if (selected == null || !list.any((p) => p.id == selected)) {
-              // pick the first portfolio once, after the list is known
-              WidgetsBinding.instance.addPostFrameCallback((_) {
-                ref.read(selectedPortfolioProvider.notifier).state = list.first.id;
-              });
-              return const Center(child: CircularProgressIndicator());
-            }
-            return const TabBarView(children: [TargetsTab(), RebalancePlanTab()]);
-          },
+        body: Column(
+          children: [
+            if (stale != null)
+              Padding(
+                padding: const EdgeInsets.fromLTRB(16, 12, 16, 0),
+                child: StaleBanner(fetchedAt: stale),
+              ),
+            Expanded(
+              child: AsyncValueView(
+                value: portfolios,
+                onRetry: () => ref.invalidate(portfoliosProvider),
+                data: (list) {
+                  if (list.isEmpty) {
+                    return const EmptyState(
+                      icon: Icons.pie_chart_outline,
+                      message: 'Портфелей пока нет.\n'
+                          'Ребалансировка считается по портфелю: заведите его в настройках счетов.',
+                    );
+                  }
+                  final selected = ref.watch(selectedPortfolioProvider);
+                  if (selected == null || !list.any((p) => p.id == selected)) {
+                    // pick the first portfolio once, after the list is known
+                    WidgetsBinding.instance.addPostFrameCallback((_) {
+                      ref.read(selectedPortfolioProvider.notifier).state = list.first.id;
+                    });
+                    return const Center(child: CircularProgressIndicator());
+                  }
+                  return const TabBarView(children: [TargetsTab(), RebalancePlanTab()]);
+                },
+              ),
+            ),
+          ],
         ),
       ),
     );

app/lib/features/rebalance/targets_tab.dart

@@ -77,7 +77,8 @@ class _TargetsTabState extends ConsumerState<TargetsTab> {
     return AsyncValueView(
       value: targets,
       onRetry: () => ref.invalidate(targetsProvider),
-      data: (set) {
+      data: (cached) {
+        final set = cached.data;
         _seed(set, '$portfolioId/$dimension');
         final draft = _draft ?? const <TargetWeight>[];
         return ListView(