feat(app): смена сервера API и очистка данных устройства при выходе

Адрес бэкенда хранится в shared_preferences и читается до runApp; switchApiBaseUrl сбрасывает токены и кэш старого сервера. Выход стирает refresh-токен и sqlite-кэш ответов. Экран настроек переделан под разделы.

app/lib/core/auth/auth_controller.dart

@@ -2,6 +2,7 @@ import 'package:dio/dio.dart';
 import 'package:fintracker_api/fintracker_api.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 
+import '../cache/response_cache_provider.dart';
 import '../config.dart';
 import 'token_store.dart';
 
@@ -20,14 +21,18 @@ final tokenStoreProvider = Provider<TokenStore>((_) => TokenStore());
 
 /// A bare Dio for auth calls: no auth interceptor, so a refresh can never recurse.
 final authDioProvider = Provider<Dio>(
-  (_) => Dio(BaseOptions(
-    baseUrl: apiBaseUrl(),
-    connectTimeout: const Duration(seconds: 10),
-    receiveTimeout: const Duration(seconds: 20),
-  )),
+  (ref) => Dio(
+    BaseOptions(
+      baseUrl: ref.watch(apiBaseUrlProvider),
+      connectTimeout: const Duration(seconds: 10),
+      receiveTimeout: const Duration(seconds: 20),
+    ),
+  ),
 );
 
-final authControllerProvider = NotifierProvider<AuthController, AuthState>(AuthController.new);
+final authControllerProvider = NotifierProvider<AuthController, AuthState>(
+  AuthController.new,
+);
 
 class AuthController extends Notifier<AuthState> {
   @override
@@ -51,7 +56,9 @@ class AuthController extends Notifier<AuthState> {
 
   Future<String?> login(String email, String password) async {
     try {
-      final r = await _api.authLogin(loginRequest: LoginRequest(email: email, password: password));
+      final r = await _api.authLogin(
+        loginRequest: LoginRequest(email: email, password: password),
+      );
       await _accept(r.data!);
       return null;
     } on DioException catch (e) {
@@ -64,32 +71,51 @@ class AuthController extends Notifier<AuthState> {
     final token = refresh ?? await _store.readRefresh();
     if (token == null) return false;
     try {
-      final r = await _api.authRefresh(refreshRequest: RefreshRequest(refreshToken: token));
+      final r = await _api.authRefresh(
+        refreshRequest: RefreshRequest(refreshToken: token),
+      );
       await _accept(r.data!);
       return true;
     } on DioException catch (e) {
-      if (e.response?.statusCode == 401) await _store.clear();
+      if (e.response?.statusCode == 401) await _wipeLocal();
       return false;
     }
   }
 
   Future<void> _accept(TokenPair pair) async {
     await _store.writeRefresh(pair.refreshToken);
-    state = AuthState(AuthStatus.signedIn, accessToken: pair.accessToken, email: state.email);
+    state = AuthState(
+      AuthStatus.signedIn,
+      accessToken: pair.accessToken,
+      email: state.email,
+    );
   }
 
   Future<void> logout() async {
     final refresh = await _store.readRefresh();
     if (refresh != null) {
       try {
-        await _api.authLogout(refreshRequest: RefreshRequest(refreshToken: refresh));
+        await _api.authLogout(
+          refreshRequest: RefreshRequest(refreshToken: refresh),
+        );
       } on DioException {
         // the server may already consider it revoked; local state wins
       }
     }
-    await _store.clear();
+    await _wipeLocal();
     state = const AuthState(AuthStatus.signedOut);
   }
+
+  /// Everything this device keeps for the account: the refresh token and the cached
+  /// responses (the whole financial picture, in plain sqlite / IndexedDB).
+  Future<void> _wipeLocal() async {
+    await _store.clear();
+    try {
+      await ref.read(responseCacheDbProvider).clear();
+    } on Object {
+      // the token is already gone; a cache that cannot be opened must not block signing out
+    }
+  }
 }
 
 /// Human-readable text from an RFC 7807 body, falling back to the transport error.
@@ -102,8 +128,7 @@ String problemMessage(DioException e) {
   return switch (e.type) {
     DioExceptionType.connectionError ||
     DioExceptionType.connectionTimeout ||
-    DioExceptionType.receiveTimeout =>
-      'Сервер недоступен',
+    DioExceptionType.receiveTimeout => 'Сервер недоступен',
     _ => e.message ?? 'Ошибка запроса',
   };
 }

app/lib/core/auth/switch_server.dart

@@ -0,0 +1,17 @@
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+
+import '../config.dart';
+import 'auth_controller.dart';
+
+/// Points the app at [url] (null = the default). A different server means a different
+/// account, so the session ends first — while the clients still talk to the OLD server, so
+/// the refresh token is revoked there and never sent to the new one — and only then is the
+/// address changed. Takes a container rather than a `WidgetRef`: signing out replaces the
+/// calling screen, and a disposed widget's `ref` throws.
+Future<void> switchApiBaseUrl(ProviderContainer container, String? url) async {
+  final next = url ?? defaultApiBaseUrl();
+  if (next != container.read(apiBaseUrlProvider)) {
+    await container.read(authControllerProvider.notifier).logout();
+  }
+  await container.read(apiBaseUrlProvider.notifier).save(url);
+}

app/lib/core/auth/token_store.dart

@@ -4,12 +4,13 @@ import 'package:flutter_secure_storage/flutter_secure_storage.dart';
 /// (single-user, TLS-only deployment; see plan §7 open question 1).
 class TokenStore {
   TokenStore([FlutterSecureStorage? storage])
-      : _storage = storage ?? const FlutterSecureStorage();
+    : _storage = storage ?? const FlutterSecureStorage();
 
   final FlutterSecureStorage _storage;
   static const _refreshKey = 'refresh_token';
 
   Future<String?> readRefresh() => _storage.read(key: _refreshKey);
-  Future<void> writeRefresh(String token) => _storage.write(key: _refreshKey, value: token);
+  Future<void> writeRefresh(String token) =>
+      _storage.write(key: _refreshKey, value: token);
   Future<void> clear() => _storage.delete(key: _refreshKey);
 }