Introduce manifest-driven archive import/export support and fix Folder adapter registration.

- Add comprehensive archive/ZIP import handling in StrategyProvider: manifest parsing/validation, zip & legacy imports, folder & strategy mapping, theme profile remapping/restoration, undeclared-file detection, and helper utilities for extracting/writing archive entries. Also add import-from-file-picker and several small robustness fixes (temp dirs, path normalization, error reporting).
- Add FolderAdapter implementation to hive_adapters.dart and centralize adapter registration behind new hive_registration.dart (registerIcarusAdapters / registerIcarusIsolatedAdapters) to avoid duplicate registration; update main.dart to use the new registration entrypoint.
- Handle missing platform directory plugins in image provider by falling back to systemTemp and import flutter/services.dart for MissingPluginException.
- Ensure built-in map theme profiles set createdAt when bootstrapping in map_theme_provider.
- Add new services/archive_manifest.dart (archive manifest model/logic) and update tests to match import behavior.

These changes enable reliable manifest-based library backups, folder-tree exports, and safer adapter registration across platforms.