- Add TodoEntity, TodoDao, TodoRepository, and TodoRepositoryImpl for local todo storage with sync support
- Implement TodoViewModel with CRUD operations, group management, and subtask handling
- Create TodoScreen with Kanban-style board view, group-based organization, and drag-to-reorder support
- Add BrainDumpSheet for AI-powered task extraction from natural language input using Gemini API
- Implement TodoNot