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/api/api_client.dart

@@ -4,27 +4,21 @@ import 'package:flutter_riverpod/flutter_riverpod.dart';
 
 import '../auth/auth_controller.dart';
 import '../cache/cache_interceptor.dart';
-import '../cache/response_cache.dart';
+import '../cache/response_cache_provider.dart';
 import '../config.dart';
 
-/// One sqlite-backed cache of the last successful GET per endpoint+params,
-/// shared by every screen. See `docs/ai/offline-cache.md`.
-final responseCacheDbProvider = Provider<ResponseCacheDatabase>((ref) {
-  final db = ResponseCacheDatabase();
-  ref.onDispose(db.close);
-  return db;
-});
-
 /// Authenticated client: bearer header on every call, one transparent refresh
 /// on 401, and — since [CacheInterceptor] is added last, so it sees a request
 /// only after auth has already handled it — the last cached answer when the
 /// network itself is unreachable.
 final apiProvider = Provider<FintrackerApi>((ref) {
-  final dio = Dio(BaseOptions(
-    baseUrl: apiBaseUrl(),
-    connectTimeout: const Duration(seconds: 10),
-    receiveTimeout: const Duration(seconds: 30),
-  ));
+  final dio = Dio(
+    BaseOptions(
+      baseUrl: ref.watch(apiBaseUrlProvider),
+      connectTimeout: const Duration(seconds: 10),
+      receiveTimeout: const Duration(seconds: 30),
+    ),
+  );
   dio.interceptors.add(DateQueryInterceptor());
   dio.interceptors.add(_AuthInterceptor(ref));
   dio.interceptors.add(CacheInterceptor(ref.watch(responseCacheDbProvider)));
@@ -67,7 +61,10 @@ class _AuthInterceptor extends QueuedInterceptor {
   }
 
   @override
-  Future<void> onError(DioException err, ErrorInterceptorHandler handler) async {
+  Future<void> onError(
+    DioException err,
+    ErrorInterceptorHandler handler,
+  ) async {
     final retried = err.requestOptions.extra['retried'] == true;
     if (err.response?.statusCode != 401 || retried) return handler.next(err);
 
@@ -81,7 +78,9 @@ class _AuthInterceptor extends QueuedInterceptor {
       ..headers['Authorization'] = 'Bearer $token'
       ..extra['retried'] = true;
     try {
-      handler.resolve(await Dio(BaseOptions(baseUrl: opts.baseUrl)).fetch(opts));
+      handler.resolve(
+        await Dio(BaseOptions(baseUrl: opts.baseUrl)).fetch(opts),
+      );
     } on DioException catch (e) {
       handler.next(e);
     }