Introduce a complete service backup/restore subsystem with encrypted archives, database records and REST endpoints. Implements BackupManager with export/import for service config, platform resources (MongoDB, MinIO, ClickHouse), and Docker images; adds BackupRepository and migrations for backups table and include_image_in_backup; integrates backup flows into the HTTP API and the UI client; exposes backup password management and restore modes (restore/import/clone). Wire BackupManager into Onebox initialization.
