fix: большой фикс недочетов и фикс пары язв

lib/core/storage/app_database.dart

@@ -159,7 +159,7 @@ class AppDatabase {
     final dbPath = await getDatabasesPath();
     return openDatabase(
       join(dbPath, 'komet.db'),
-      version: 10,
+      version: 11,
       onOpen: (db) => db.execute('PRAGMA foreign_keys = ON'),
       onCreate: (db, _) => _createTables(db),
       onUpgrade: (db, oldVersion, newVersion) async {
@@ -209,6 +209,9 @@ class AppDatabase {
             'ALTER TABLE chats_cache ADD COLUMN admins TEXT',
           );
         }
+        if (oldVersion < 11) {
+          await _createIndexes(db);
+        }
       },
     );
   }
@@ -234,6 +237,19 @@ class AppDatabase {
     await db.execute(_chatsCacheSchema);
     await db.execute(_contactsSchema);
     await db.execute(_messagesSchema);
+    await _createIndexes(db);
+  }
+
+  static Future<void> _createIndexes(Database db) async {
+    await db.execute(
+      'CREATE INDEX IF NOT EXISTS idx_messages_chat ON messages(account_id, chat_id, time DESC)',
+    );
+    await db.execute(
+      'CREATE INDEX IF NOT EXISTS idx_chats_account ON chats_cache(account_id, last_event_time DESC)',
+    );
+    await db.execute(
+      'CREATE INDEX IF NOT EXISTS idx_contacts_account ON contacts(account_id)',
+    );
   }
 
   static const _contactsSchema = '''

lib/core/storage/token_storage.dart

@@ -1,22 +1,50 @@
+import 'package:flutter_secure_storage/flutter_secure_storage.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 
 class TokenStorage {
   static const _tokenPrefix = 'auth_token_';
   static const _activeAccountKey = 'active_account_id';
 
+  static const _secure = FlutterSecureStorage(
+    aOptions: AndroidOptions(encryptedSharedPreferences: true),
+  );
+
+  static Future<void> writeSecure(String key, String value) async {
+    await _secure.write(key: key, value: value);
+  }
+
+  static Future<String?> readSecure(String key) async {
+    return _secure.read(key: key);
+  }
+
+  static Future<void> deleteSecure(String key) async {
+    await _secure.delete(key: key);
+  }
+
   static Future<void> saveToken(String token, int accountId) async {
-    final prefs = await SharedPreferences.getInstance();
-    await prefs.setString('$_tokenPrefix$accountId', token);
+    await _secure.write(key: '$_tokenPrefix$accountId', value: token);
   }
 
   static Future<String?> readToken(int accountId) async {
+    final key = '$_tokenPrefix$accountId';
+    final secured = await _secure.read(key: key);
+    if (secured != null) return secured;
+
     final prefs = await SharedPreferences.getInstance();
-    return prefs.getString('$_tokenPrefix$accountId');
+    final legacy = prefs.getString(key);
+    if (legacy != null) {
+      await _secure.write(key: key, value: legacy);
+      await prefs.remove(key);
+      return legacy;
+    }
+    return null;
   }
 
   static Future<void> deleteToken(int accountId) async {
+    final key = '$_tokenPrefix$accountId';
+    await _secure.delete(key: key);
     final prefs = await SharedPreferences.getInstance();
-    await prefs.remove('$_tokenPrefix$accountId');
+    await prefs.remove(key);
   }
 
   static Future<void> setActiveAccount(int accountId) async {