Complete migration from SharedPreferences to Room database architecture:
**New Components:**
- NotificationContentEntity: Core notification data with encryption support
- NotificationDeliveryEntity: Delivery tracking and analytics
- NotificationConfigEntity: Configuration and user preferences
- NotificationContentDao: Comprehensive CRUD operations with optimized queries
- NotificationDeliveryDao: Delivery analytics and performance tracking
- NotificationConfigDao: Configuration management with type safety
- DailyNotificationDatabase: Room database with migration support
- DailyNotificationStorageRoom: High-level storage service with async operations
**Key Features:**
- Enterprise-grade data persistence with proper indexing
- Encryption support for sensitive notification content
- Automatic retention policy enforcement
- Comprehensive analytics and reporting capabilities
- Background thread execution for all database operations
- Migration support from SharedPreferences-based storage
- Plugin-specific database isolation and lifecycle management
**Architecture Documentation:**
- Complete ARCHITECTURE.md with comprehensive system design
- Database schema design with relationships and indexing strategy
- Security architecture with encryption and key management
- Performance architecture with optimization strategies
- Testing architecture with unit and integration test patterns
- Migration strategy from legacy storage systems
**Technical Improvements:**
- Plugin-specific database with proper entity relationships
- Optimized queries with performance-focused indexing
- Async operations using CompletableFuture for non-blocking UI
- Comprehensive error handling and logging
- Data validation and integrity enforcement
- Cleanup operations with configurable retention policies
This completes the high-priority storage hardening improvement, providing
enterprise-grade data management capabilities for the DailyNotification plugin.
Co-authored-by: Matthew Raymer
