feat(auth): implement API key authentication and management

Introduce a new API key authentication mechanism to support service-to-service
communication (e.g., Airflow, CI/CD) without browser-based JWT login.

- Add `APIKey` model and `APIKeyPrincipal` dependency for RBAC.
- Implement `require_api_key_or_jwt` dependency with environment scoping.
- Add admin CRUD endpoints for API key lifecycle management.
- Add API key management UI in System Settings.
- Update maintenance API to support explicit `environment_id` and API key auth.
- Add i18n support for API keys and connection settings.
- Include Python and Bash usage examples in the `examples/` directory.
- Update technical specifications and documentation.

README.md

@@ -438,3 +438,12 @@ pip install -r requirements.txt --upgrade
 cd frontend
 npm install
 ```
+
+## 💻 Примеры скриптов
+
+Примеры Python и Bash скриптов для вызова API ss-tools из внешних систем (Airflow, CI/CD, cron) находятся в каталоге [`examples/`](./examples/).
+
+- **Python** — [`examples/maintenance-api-python.py`](./examples/maintenance-api-python.py)
+- **Bash**  — [`examples/maintenance-api-bash.sh`](./examples/maintenance-api-bash.sh)
+
+Скрипты демонстрируют аутентификацию через API Key (`X-API-Key`), запуск и завершение maintenance-событий, а также обработку ошибок.