Updated the database migration logic to consolidate provider API sources from both accounts and heuristic methods for BILLmanager URLs. Replaced direct calls to `consolidateProviderApiFromAccounts` with `consolidateAllProviderApiSources` in relevant routes to ensure comprehensive API data handling.
- Added new backup and restore functionality for JSON and SQLite database formats.
- Implemented notification settings for low balance alerts and sync digests in the settings page.
- Updated database schema to include new columns for balance alert thresholds and notification preferences.
- Refactored synchronization logic to provide detailed summaries and improved error handling.
- Enhanced user interface for managing accounts and settings, including new input fields for balance alerts.
- Improved sync log display to include summary information for better tracking of synchronization results.