- Add SQLite and UUID dependencies (go-sqlite3, google/uuid)
- Create database connection with automatic migrations
- Implement UserRepository with full CRUD operations
- Implement HabitRepository with JSON serialization for arrays
- Implement HabitEntryRepository with date range queries
- Add comprehensive test coverage for all repositories
- Fix User entity to default timezone to UTC when empty
- All tests passing with TDD approach (Red-Green-Refactor)
