feat: Add AIVPN support and enhance client statistics tracking

- Introduced AIVPN server detection and statistics fetching in ServerMonitoring.
- Implemented AIVPN client statistics handling in VpnClient, including raw and offset counters for traffic.
- Enhanced AWG parameters to include S3 and S4.
- Updated database schema to accommodate new AIVPN statistics fields.
- Added a script for remote reset and reinstallation of protocols.
- Improved client view template to ensure proper display of connection instructions.
- Added translations for connection instructions in multiple languages.
- Ensured host-level NAT for AWG subnet in VpnServer.

migrations/061_fix_client_connection_instructions_translation.sql

@@ -0,0 +1,11 @@
+-- Ensure clients.connection_instructions exists in all locales used by UI.
+-- Without this key, client view heading may be missing or fallback text can appear inconsistent.
+
+INSERT INTO translations (locale, category, key_name, translation) VALUES
+('en', 'clients', 'connection_instructions', 'Connection Instructions'),
+('ru', 'clients', 'connection_instructions', 'Инструкции по подключению'),
+('es', 'clients', 'connection_instructions', 'Instrucciones de conexión'),
+('de', 'clients', 'connection_instructions', 'Verbindungsanweisungen'),
+('fr', 'clients', 'connection_instructions', 'Instructions de connexion'),
+('zh', 'clients', 'connection_instructions', '连接说明')
+ON DUPLICATE KEY UPDATE translation = VALUES(translation);