…a new `.pxpl` file format (ZIP-based) and robust validation pipelines.

- **New Backup System (v3)**:
    - Replaces the legacy GZIP format with a ZIP-based structure containing a `manifest.json` and individual module JSON files.
    - Introduces `BackupManager`, `BackupWriter`, and `BackupReader` to handle the new format while maintaining backward compatibility for v1/v2 backups via `LegacyPayloadAdapter`.
    - Adds `BackupSection` to define exportable modules, including new support for **Artist Images**, **Equalizer Presets**, and **QuickFill Genres**.

- **Validation & Security**:
    - Implements a multi-stage `ValidationPipeline` including file-level checks (size, extension), ZIP safety (path traversal, zip bomb protection), manifest integrity, and SHA-256 checksum verification for module payloads.
    - Adds `ModuleSchemaValidator` and `ContentSanitizer` to ensure imported data meets structural and security requirements.

- **Restore Improvements**:
    - Adds a "transactional" restore process in `RestoreExecutor` with snapshot-based rollback capabilities to prevent data corruption on partial failures.
    - Introduces a "Restore Plan" phase that allows users to inspect backup metadata (device info, app version, module sizes) and select specific modules before importing.

- **UI & UX**:
    - Completely overhauled the Import UI in `SettingsCategoryScreen` with a multi-step flow: file selection, backup inspection, and module-specific configuration.
    - Implements a **Backup History** system in `BackupHistoryRepository` to track and quickly re-import recent backup files.
    - Enhanced progress reporting for both export and import operations with detailed step descriptions.

- **Data & Persistence**:
    - Updates `UserPreferencesRepository` to improve type safety and fallback logic during preference restoration.
    - Adds specialized `BackupModuleHandler` implementations for all data types (Playlists, Favorites, Lyrics, Stats, etc.) to encapsulate serialization logic.
    - Deprecates the old `AppDataBackupManager`.