Closes#45
SettingsScreen:
- Server-URL and API-Key input fields (API-Key masked as password)
- Push (upload) and Pull (download) sync buttons
- Sync status indicator (running/success/error)
- Last sync timestamp display (persisted via Room settings)
SettingsViewModel:
- Inject SyncService for server communication
- pushSync(): exports local inventory to InventoryDto, uploads via SyncService
- pullSync(): downloads InventoryDto from server, imports into local DB
- Persists server_url, api_key, sync_last_timestamp in Room settings table
ImportExportRepository:
- New methods exportToInventoryDto() and importFromInventoryDto()
- Refactored to eliminate code duplication via buildInventoryDto() and
applyInventoryDto() helper methods
Tests:
- 8 new ViewModel tests covering sync settings loading, push/pull success,
push/pull error scenarios, and sync status dismissal
- FakeSyncService and extended FakeImportExportRepository for testing
a972ce34ca